How can I tell if a lump or bump is cancerous?

Tumors of the skin and subcutaneous (tissue just underneath the skin) are the most common tumors affecting dogs and the second most common tumors affecting cats.

There are a wide variety of tumors that can occur within the skin, and it is very important to remember that not every skin tumor is cancerous. In fact, the vast majority — 80 percent — of skin tumors in dogs are considered to be benign, meaning they do not metastasize (spread) to other locations in the body.

This is in contrast to skin tumors in cats, where 50-65 percent of tumors are malignant, meaning they grow as very locally invasive masses and have a higher chance of metastasizing to distant sites.

Unfortunately, a veterinarian cannot tell if a tumor is benign or malignant just by visualizing or palpating the mass. Further tests are necessary to be able to determine exactly what kind of tumor the lump or bump could be.

There are two main ways to determine whether a skin tumor is benign or malignant. The first involves performing what is known as a fine needle aspirate with cytological analysis. This non-invasive procedure generally entails introducing a small gauge needle (about the same size that is used to draw a blood sample or administer a vaccination) into the tumor and attaching a small syringe to the needle and aspirating (literally “sucking up”) some of the cells into the syringe. The cells are then dispersed onto a microscope slide, special stains are applied to the sample, and the slide is then evaluated under a microscope. The assessment may be performed “in house” by the veterinarian examining the patient, or, more often, the sample is sent to a laboratory where a cytopathologist (veterinarian with specialized training in the evaluation of samples of this nature) will examine the slides and make a diagnosis.

There are several advantages to this type of sampling. It is considered a rapid, non-painful, simple procedure to perform, and is usually relatively inexpensive. In most cases, fine needle aspirates can be performed while the patient is awake. If the tumor is located in a particularly sensitive area (e.g., around the eyes or anus), a veterinarian may recommend that the patient be lightly sedated to facilitate sampling in a safe manner. Fine needle aspirates will give information about the characteristics of the individual cells comprising a tumor, and can often be useful for being able to determine if a tumor is cancerous or not.

The main disadvantage to this form of sampling is it may not prove to be the most accurate because this type of analysis examines only individual cells. It also may not be accurate for determining the exact type of cancer the tumor may be. There is also the possibility that the sample may return non-diagnostic, meaning no cellular material could be obtained. Finally, since the size of the needle used to sample the tumor is very small, it is possible to miss the portion of the tumor containing the cancerous cells and a misdiagnosis could be made.

A more accurate way of sampling skin tumors from dogs and cats involves performing what is known as a tissue biopsy. There are several ways to obtain a tissue biopsy; all of which usually involve either heavy sedation or general anesthesia.

The veterinarian will first decide whether to perform what is known as an incisional or excisional biopsy. For either procedure, the fur covering the skin over the tumor will be clipped and sterilized. For incisional biopsies, small pieces of the tumor will be procured. The veterinarian obtaining the sample may do so by using a needle slightly larger than the one used to perform a fine needle aspirate, a special biopsy instrument known as a punch biopsy, or simply use a scalpel blade to remove a small block of tissue from the tumor. Excisional biopsies generally require more advanced pre-surgical planning, and in these instances the goal is to remove the tumor in its entirety.

In all cases of biopsy, the tissue will be placed into formalin (a special liquid that “fixes” tissue) and will be submitted to a laboratory for histological analysis by a pathologist. This process generally takes about 5-7 days.

The main advantage of performing a biopsy is the higher degree of an accurate final diagnosis. Biopsy samples can also include information about whether or not cancer cells are seen invading into blood vessels or lymphatic vessels, which could indicate a higher chance of metastasis. If an excisional biopsy was performed, biopsy reports can include whether or not the tumor was entirely removed. The main disadvantages are that biopsy procedures require heavier sedation or anesthesia, the results take longer to return, they are considered slightly more invasive, and can be more costly.

If you notice a new lump or bump on your pet, you should have it evaluated by your veterinarian as soon as possible. During the visit, the tumor should be measured and its location “mapped,” either by physically drawing a picture of the location of the tumor on your pet, or by taking a photograph of the tumor and making it a part of your pet’s medical record. You and your veterinarian can discuss what would be the best plan for evaluating the tumor.

If the tumor is determined to be benign, you will need to continue monitoring it for any signs of change in size, shape, or consistency, as this could indicate transformation to a more malignant behavior. If the tumor is determined to be malignant, your veterinarian may recommend referring you to a veterinary surgeon or veterinary oncologist for further testing. If noticed early, some malignant skin tumors can be treatable and the prognosis excellent. The best way to examine your pet for skin tumors is simply by petting them or grooming them, and also by scheduling regular physical examinations with your veterinarian.


What is one of the hardest jobs in the veterinary field?

One of the most important people you will encounter in your veterinarian’s office is the receptionist who greets you when you walk through the door.

This is especially true for doctors like me who work in the veterinary referral industry. We do not evaluate healthy puppies or kittens, nor do we typically find our schedule filled with routine wellness visits. Our patients were previously diagnosed with some disorder or disease process, necessitating referral to our facility for further diagnostic and/or treatment options. Therefore, owners seek care from specialists because their pet is experiencing a problem with their health.

When owners cross through the entrance to our hospital, they are filled with anxiety and apprehension, and their emotional turmoil is palpable from the moment of their arrival. The receptionist is the first person they will meet and the quality of this initial interaction can set the tone for not only the remainder of their first visit, but for all subsequent interactions.

My goal is for each owner I encounter to feel important, comforted, relaxed, and as if they are they only pet on my appointment schedule for the day. If a receptionist can correctly identify the patient by name (and gender), this seemingly insignificant gesture often means a great deal to a distraught pet parent hoping for even just a tiny sense of reassurance.

In many referral hospitals, receptionists are also the people given the duty of answering all incoming calls. They are expected to do so with a maximum of one ring, to always be polite and cheerful, and to speak in a clear voice with an even cadence.

This is equally true on a busy day when they may be dealing with several different tasks simultaneously as is it on a slow one where those expectations may not be as daunting. Receptionists need to keep calm under high pressure situations and never let on to an owner that they have nothing but all the time in the world to help that person deal with their needs.

At our hospital, owners will often call and ask receptionists for advice rather than schedule a consult with a doctor. It is inappropriate for a receptionist to make medical recommendations to owners or to suggest treatment options when owners are looking for a guarantee that it’s okay to not bring their pet in for evaluation.

Receptionists need to be capable of directing owners to the correct person who can adequately answer the questions being posed, but also remain sympathetic to the client’s needs. Therefore, it is imperative for a receptionist to be intelligent, reliable, somewhat medically trained, but also acutely aware of their limitations and when potential lines are close to being crossed.

At many hospitals, and especially those tasked with emergency/urgent care, receptionists are required to triage pets experiencing urgent/life-threatening conditions from those who are stable and able to wait a short while before being seen. This can occur either via a telephone conversation or when the client/patient arrives without an appointment. They often need to make a split-second determination if the situation requires emergency attention, so they should have fundamental training for what to look for to facilitate making that judgment.

Receptionists are often tasked with collecting payments and/or deposits on pet’s bills. They are the frontline individuals dealing with finances and this can lead to some heated “conversations” and emotionally driven interactions, especially in emergency cases.

There are dozens of other responsibilities placed on receptionists, including filing, faxing, scheduling follow-up appointments, dispensing medications, fixing office equipment, and cleaning. These are typically considered the “practical” aspects of their job descriptions.

On the less technically tangible side are the receptionist’s obligations towards calming down anxious or irate clients, working alongside impatient doctors and technicians, and quite literally being emotionally and personally perfect and cheerful at all times.

Receptionists need to be able to accomplish these assignments even when they don’t feel like being particularly jovial or enthusiastic. They need to treat each owner individually and respectfully, even if the person they just spoke to on the phone berated them for charging inordinate prices or not providing them with urgent medical advice.

I’ve read that the job description for a veterinary receptionist requires no specific skill set and no experience. I would argue that for a receptionist to be successful, they need to possess excellent communication skills, advanced technological capabilities, and be able to multi-task without thinking too hard about it.

Additionally, they must possess attributes including kindness, compassion, patience, and like so many of us in the veterinary field, a thick skin to be able to deal with irate and emotional pet owners who sometimes forget to be polite.

I’ve always said I could never do the jobs that the front desk staff performs at my hospital, and I’m extremely grateful to work alongside competent and friendly staff members who toil away so enthusiastically at their responsibilities.

And I very much appreciate their ability to shield me from many of the typical daily tasks they so willingly take on in order to make my day flow as smoothly as possible.

“I thought it was just a little limp…” Part 3: Palliative options for canine osteosarcoma

Thus far I’ve discussed various methods we use to diagnose dogs with osteosarcoma and the staging tests for canine osteosarcoma. In the following two articles I will describe palliative and definitive treatment options for this disease, and their respective prognoses.

To review, osteosarcoma is an aggressive form of bone cancer in dogs. Most tumors arise within weight-bearing bones, and the majority of dogs are presented to their veterinarians because of lameness. In most cases, the recommendation will be to amputate the affected limb, and with this surgery, the expected prognosis is about 4-5 months.

The short survival time is because this cancer usually has already spread to distant sites in the body before we are able to detect it. Amputating a limb without further therapy is considered palliative treatment, but remains the most effective way to remove the source of pain for the patient.

Many owners fear amputation, as they believe their dog will be unable to ambulate on three limbs, or that the loss of a limb will somehow alter their dog’s personality/demeanor. In my experience, this is exceedingly rare.

A very good resource of information about amputation is Tripawds, where the motto is “It’s better to hop on three legs than limp on four.” Here, owners of three-legged pets provide a fantastic support network for each other and for owners considering surgery. One can find a group of “peers” to bounce questions off of and read personal experiences on individual blog pages and forums. I also direct owners to search “Three-legged dogs” on youtube, as there are thousands of videos of dogs racing around after amputation, helping to support the notion that amputation is neither cruel nor debilitating.

For cases where amputation is not an option, or when owners will not consider this procedure, alternative palliative measures can be attempted as a means to reduce pain.

In human cancer terms, palliative treatments are designed to alleviate clinical signs related to the tumor(s), but are not necessarily expected to extend that patient’s lifespan.

In veterinary medicine, if palliative options are successful in controlling pain related to cancer, patients will often live longer than they would if their signs were not controlled, simply because their quality of life is vastly improved and euthanasia can be delayed. Survival may only be extended by a few weeks to months, but for many owners this is exactly what they need to come to terms with the diagnosis and enjoy good quality time with their pets.

One very effective form of palliative treatment for dogs with osteosarcoma is radiation therapy. During radiation therapy, high-energy beams of radiation are applied to a tumor from an external source. Most facilities treating dogs with radiation use a linear accelerator machine. Treatment protocols vary, but may consist of one treatment a week for 4-6 weeks, or consecutive daily treatments for 2-5 days. Studies indicate around 70-90 percent of dogs will show improvement in their pain scores, with most dogs showing improvement with just one treatment.

Dogs can develop fairly significant localized skin reactions with this form of radiation, with hair loss, ulceration, scabbing, and swelling seen in many cases. Palliative radiation therapy also causes increased susceptibility to fracturing an already weakened bone. This is likely from a combination of activity and stress on the limb because the pet feels better, and because the radiation therapy could inherently cause damage to the bone.

Stereotactic radiation therapy is a newer form of radiation available at some university and referral hospitals. This form of radiation is more localized for treating the tumor while sparing the normal tissue surrounding the tumor, therefore less likely to cause some of the side effects listed above.

Bisphosphonates are intravenous or oral medications used to treat bone pain in dogs. Drugs in this class were developed to prevent osteoporosis in post-menopausal women. They work to inhibit bone resorption, which is one of the main sources of pain in bone cancer. These medications are extremely well tolerated, with minimal to no side effects, and when used as a sole treatment options, are successful in relieving pain in 40 percent of patients.

Oral medications are the mainstay of palliative treatment for dogs with osteosarcoma. Often we are prescribing a combination of pain medications that include non-steroidal anti-inflammatories, along with strong opioid or opioid-like drugs and neuropathic pain inhibitors. Long-acting analgesic nerve blocks can also be used.

Some veterinarians advocate the use of acupuncture, homeopathic remedies, and/or physical therapy for treating bone pain. I do not have personal experience with these options, but am always open to discussing pros and cons with owners.

I recommend a combination of all of the above-mentioned options for dogs with osteosarcoma, as I truly believe a multi-modality approach is most successful. Statistics will argue that dogs treated palliatively do not live longer than dogs that undergo surgical amputation alone (about 4-5 months). However, in my clinical experience the 4-5 months for dogs with adequate pain control are far more enjoyable than for those whose pain we cannot control.

Focusing back on our patient Duffy, I discussed palliative options with his owners, especially in light of the concern for the small lesion seen within one of his lung lobes.

As with most owners, their main concern was making sure Duffy remained pain-free for as long as possible. Although they weren’t quite sure they were ready to commit to chemotherapy after surgery, they were willing to take the risk in the face of possible metastatic disease and elected to move forward with amputation of his affected limb. We were able to perform surgery the very next day, making the time from when I met Duffy to his recovery from amputation (and beginning of time pain-free) less than three days.

Next week, in the final article in this series, I will discuss the chemotherapy options for treating dogs with osteosarcoma, and what Duffy’s owners ultimately elected for his long-term treatment plan.

The bigger (and smaller) picture of cancer care in pets

There are two considerations I have before making treatment recommendations for patients diagnosed with what are known as “solid tumors” (i.e., those that develop in one tissue and can spread throughout the body).

The first is predicting how the tumor will behave in a localized sense, meaning directly at the same anatomical site where it began growing.

The second is anticipating the risk of metastasis (spread) to distant site(s) in the body.

This leaves me with several potential algorithms of outcome for any particular cancer:

1. A tumor that grows locally but has little potential for recurrence after removal and little chance for spread.

2. A tumor that grows locally and has a significant potential for recurrence after removal and little chance for spread.

3. A tumor that grows locally but has little potential for recurrence after removal and significant chance for spread

4. A tumor that grows locally and has significant potential for recurrence after removal and significant chance for spread.

Of each of those scenarios, it’s most challenging for owners to comprehend the recommendations made for treating tumors where there’s a high likelihood of regrowth after surgery and spread to distant sites in the body (#4).

For those cases, I try to clarify the muddy waters by emphasizing why it’s imperative to focus on both the “smaller” and the “bigger” pictures.

Addressing the smaller picture means we are dealing with the best way to control the local tumor itself. Examples of localized tumors include a skin growth, a bone tumor, or an intestinal mass.

The bigger picture entails assessing the patient for the presence of metastasis, either in the setting of “gross” disease (measurable tumors in other sites of the body), or “microscopic” disease (non-measurable tumor cells that we are nearly certain escaped from the primary tumor, but have not yet grown into anything we are able to visualize).

For tumors that require smaller and bigger picture treatments, ideally we obtain adequate local control over the primary tumor via aggressive surgery and/or radiation therapy and also administer systemic treatment (e.g., chemotherapy and/or immunotherapy) to address the metastatic disease.

The concept of combining localized and systemic treatments can be difficult for owners, owing to lack of access (radiation therapy is available only in select geographical areas), their own personal preference (not wanting to “put their pet through too much”), and most often finances (such combinations of treatments can easily run over $10,000 per pet).

When such limitations present themselves, I’m obligated to offer a different plan of action with the hope that I can find the “happy medium” that fits the needs of the owner and still affords their pet the best chance for long-term survival.

Another complicating factor of the smaller/bigger picture tumor is that it’s difficult to predict how pets with tumors with both aggressive localized and metastatic potential might ultimately succumb to their disease.

People readily understand that cancer is a potentially fatal disease. However, the typical assumption is the end stages of disease will entail obvious outward signs of illness, weakness, loss of appetite, pain, etc. Though often true for tumors that spread around the body, however localized tumors can be equally problematic, and ultimately life limiting for that animal.

A cat with an oral mass will still be bright and happy and purr and sleep in its favorite spot in the house. But it will eventually stop attempting to eat because it becomes too painful to ingest food.

A dog with a tumor in its urinary bladder will continue to wag its tail, ask to go for walks, eat its meals, and lie on the couch with its owners, but it will constantly painfully strain to urinate, have accidents in the home, and produce a bloody urine stream.

Whether keeping my sight short on issues related to the smaller picture of local disease or focusing on the bigger picture potential for distant spread, I have to keep an open mind regarding the health of my patients, and treat them as a whole rather than a series of specific symptoms.

This is true for making recommendations for the ideal way to treat their cancer from the time of diagnosis to the delicate treatment approach to their final days or weeks of life, and for all the days of their care in between.

As always, communication is the most important aspect of managing these patients in order to ensure everyone’s expectations are met. That way I can guarantee the short and long-term pictures remain as clear as possible during the journey we embark upon when treating a pet with cancer.

“I thought it was just a little little limp”, Part 2…

Last week I introduced you to Duffy, an older Golden retriever, whose seemingly simple limp turned out to be a harbinger for the devastating diagnosis of osteosarcoma. This week I want to go over some of the available staging tests designed to look for spread of this type of cancer, as well as provide my clinical insight into their value and utility.
The recommended treatment of choice for dogs with osteosarcoma of a weight-bearing bone is amputation of the affected limb. In only very specific cases, we may consider localized excision of the affected portion of the bone without pursuing an amputation (i.e., limb-sparing surgery). More information on this procedure will follow in a subsequent article.

Osteosarcoma is a highly metastatic tumor. The most common locations where the cancer will spread to are the lungs and to other bones. At the time of diagnosis, greater than 90 percent of dogs will test negative for spread of disease. Yet even with immediate removal of the tumor, most dogs will develop metastatic tumors within a few short months after surgery. This indicates that the cancer already spread before the primary tumor was removed, but existed at a level below our ability to detect it. The average lifespan is only expected to be about 4-5 months with amputation alone.

Given the propensity for this cancer to spread to the lungs and other bones, historically we used radiographs (X-rays) of the lungs along with our physical exam findings as the main ways to assess for spread. There are some limitations to these diagnostic tests though; in order for a metastatic tumor to be visible on a radiograph, it must be about 1cm3 in size, which is estimated to be about 1 billion cancer cells. It doesn’t take a medical degree to know that’s a huge amount of cancer cells. We also know animals do not show signs of pain the same way people do, and physical exams can be notoriously insensitive for picking up the discomfort associated with a metastatic tumor within another bone.
Advanced diagnostic tests with increased sensitivity for detecting spread of osteosarcoma tumors are now more readily available. We now recommend a thoracic CT scan as this imaging modality is superior to radiographs for picking up smaller tumors within the lungs and are also better at localizing tumors to specific portions of this tissue. We also can perform nuclear scintigraphy, which is a diagnostic test useful for picking up tumors in other skeletal bones.
CT scans and nuclear scintigraphy are wonderful testing options, but tend to be limited in their availability, are expensive, and have the downside of requiring heavy sedation and/or general anesthesia. They also have their own particular false positive and false negative rates and are qualitative tests, meaning they rely on human interpretation and operator error, which sometimes contributes to confusing results.
Some veterinarians recommend performing abdominal ultrasounds as a screening test on dogs with bone tumors. The odds of a bone tumor spreading to an internal organ would be exceedingly low, but the odds of an abdominal ultrasound picking up one or more abnormalities of indeterminate significance would be moderate. Typically this leads to further tests, which themselves may or may not be conclusive. All the while we have a painful patient and confused and emotional owners who are simply looking for the right thing to do for their dog.
Advanced testing options are great, but when I discuss their utility with owners, I really try to put the focus on determining what their goal is for their dog. We have to ask ourselves what we will do with the results of the test before performing it, and will these results alter the recommended treatment plan?
Dogs with osteosarcoma are painful, and although there are several available palliative treatment options, each falls considerably short in their ability to control pain when compared to amputation. If a CT scan shows hundreds of tiny tumors throughout all lung lobes, I agree the prognosis for long-term survival is poor. But do we not consider amputation of that pet’s limb to control pain while they are still asymptomatic for spread? What if the scan shows two tumors, or just a possible tumor? How do we decide the right answer?
In my opinion, whether metastases are detected or not at the time of diagnosis, surgical amputation of the affected limb in an otherwise asymptomatic dog is something I will recommend in nearly all cases. I didn’t always feel this way, and this stance is something I’ve adopted through my years of working as an oncologist trying to medically manage the discomfort of dogs with bone tumors.
Of course, not every owner elects for amputation, and not every dog is a candidate for this surgery (e.g., they may have severely debilitating orthopedic or degenerative neurological diseases that hamper their ability to ambulate even with four limbs). In those cases, we have several options for palliation of pain, each with it’s own varying success rates, which will be the subject of next week’s article.
I discussed the option of pursuing advanced testing with Duffy’s owners and they elected to pursue the thoracic CT scan, bone scintigraphy, and the abdominal ultrasound, which fortunately were all negative for any spread or intercurrent disease, with the exception of a pesky suspicious 4mm nodule in one of his left lung lobes.
And thus began the discussion of amputation versus palliative care for Duffy.
To be continued…

How much is too much?

I regularly face owners who decide not to pursue therapy for pets that have what are considered treatable cancers. The reasons for this choice can stem from concerns for too many vet visits, too much strain for the pet to go through, projection of their own feelings about cancer treatments on their pets, or financial limitations.

Over the course of my career, it hasn’t become any easier to be on the receiving end of those appointments. I want to help all pets with cancer and I want all animals to be afforded the opportunity to undergo the ideal plan to afford them the best chance of survival. Logically, I know this isn’t a realistic expectation. But it’s an accepted part of my job, and it forces me to remain open-minded about my professional goals.

Consider the opposite scenario. Those owners who want to do everything for pets that have been diagnosed with a form of cancer that has no known beneficial therapeutic option, or where we’ve run out of choices with any realistic expectation of helping them fight their disease. Those cases create a different sense of anxiety for my soul.

Practically, this translates into a scenario where the “frontline” therapy fails to keep a patient cancer-free, yet they remain relatively asymptomatic for their condition. I need to be prepared with a back up plan. In those cases, most owners want to know what else can be done to help maintain their pets’ quality of life.

My goal as a veterinarian is to make all decisions about my patient’s care using evidence-based information. I want to be sure the recommendations I present are medically sound and proven to be of a benefit.

Unfortunately, evidence based information is severely lacking in veterinary oncology and a startling amount of choices are made using simple inferences, experience, and logic.

The good news is that the more common cancers (e.g., lymphoma, osteosarcoma, mast cell tumors) do actually have fairly specific preliminary treatment algorithms. Different oncologists will offer subtle variations on the same theme, but for the most part we agree on the same initial plan of attack.

What many owners find confusing is that once we’ve moved past the primary recommendation, there are usually no universally agreed upon “next best” options amongst our oncology community. Just because I possess solid research-based information about how to treat one disease at the onset does not mean there’s enough evidence to support what the next best plan of action could be. The same is true for those cancers with no accepted initial standard of care. For those cases, we just face the confusion a bit earlier on in the plan.

Using an example of a dog with lymphoma, oncologists typically endorse a multi-drug injectable chemotherapy protocol that lasts about 6 months in duration. This plan offers the average patient about 1 – 2 years of survival. Many owners are willing to pursue this plan because of the low chance of side effects and the ability to maintain an excellent quality of life well beyond the treatment period.

However, despite being considered our most valuable and effective protocol, 95% percent of dogs with lymphoma are not cured with this plan. Therefore, more often than not, I need to be prepared to offer owners “something else” to help their pet when the cancer resurfaces.

There are numerous “rescue” protocols for such cases. In actuality, few owners are willing to try such second and third line protocols for their dogs with cancer. Many times they perceive the disease relapse as the real indicator that their pet truly has a fatal disease. Other times, a myriad of emotional, physical, financial, and ethical considerations factor in to the decision-making process.

The most difficult scenario occurs when pets are asymptomatic for their disease and I have no suitable options to help them battle their disease. It may seem counterintuitive to feel frustrated at not being able to make an animal that already feels good any different, but it’s a core part of my work.

I want to be able to keep trying to help pets with cancer, not only for their owner’s sake, but also for their own happiness and well-being. Even when a diagnosis of a cancer known to be 100% fatal is on the table, if the animal feels good, and the owners are happy with it’s quality of life, then I am always willing to try to come up with an alternative plan.

Sometimes it’s because I want to be able to give owners some form of hope. Other times it’s because I want to try a new therapy or idea and see if it can help. Mostly it’s because I want to be able to kick a patient’s cancer down as much as possible.

I can appreciate how owners might read my honesty as lack of experience, or “hedging” on telling them how we should proceed. Most people I meet prefer the simpler approach to treating their pets’ cancer. They want me to make a recommendation they can agree, or not agree, to follow.

The most important point I can make in any of these scenarios is that “just because we can, doesn’t mean we should.” This is the phrase I tell all owners when making such difficult choices about their pet’s cancer care.

It’s how I remind everyone involved in the process to keep the right perspective and to make sure we truly first do no harm.

Because sometimes it’s not cancer!

Meet Mocha! She’s a patient I recently saw  who was referred for possibly having a lung tumor. The outcome was much better than everyone expected!

The story is a great example of collaboration between veterinary specialists as well as why it’s so important we don’t put “blinders” on and keep an open mind to the possible outcomes for our pets!

Can blood work diagnose cancer in pets?

“Isn’t there a blood test you can do that will tell you if it’s cancer or not?”

If I had a dollar for every time I’ve been asked that question, well, I’d have a lot of dollars.

If I could invent a test that I truly believed could answer the question with accurate, honest, and reliable results, I’d have a lot more dollars.

Routine lab work is a fundamental part of staging a pet’s cancer. When I order those tests, I am ensuring that my patient is systemically healthy and that there are no “warning signs” of trouble regarding things such as organ function or electrolyte status.

However, such tests rarely provide information about a pet’s cancer status. With few exceptions (e.g., a very high white blood cell count could indicate a pet has leukemia or an elevated blood calcium level could result from several different types of cancers), lab work will not accurately inform me whether or not a pet has cancer.

There’s a difference between performing a test because we are suspicious that a pet could have cancer, and performing a test in a healthy patient to rule in/out a predisposition to cancer or occult (hidden) cancer that has not yet manifested with any clinical signs.

The latter scenario describes what are known as screening tests. These are tests designed to survey large populations and to “weed out” those individuals with a particular disease from those who are truly healthy.

The precise objectives vary, but most screening tests are designed to quantitate the presence of “biomarkers.” Biomarkers are measurable indicators of particular biological states or conditions and can be used to detect, screen, diagnose, treat, and monitor disease.

There are several commercially available tests available that examine different biomarkers for both cats and dogs. When we consider screening tests for cancer, most frequently, assays measure serum levels of thymidine kinase (TK) and C-reactive protein (CRP). The utility of these markers is not well established but emphasis is often placed on their ability to detect what we refer to in the medical profession as minimal residual disease (MRD).

TK is a protein involved in DNA synthesis and is expressed in dividing cells. TK levels increase with increased rate of cellular proliferation. TK levels correlate to the proliferative activity of lymphoid cells (and less likely with proliferation of other kinds of tumor cells). Elevated TK levels are also associated with viral infections and inflammatory conditions.

Serum TK levels tend to be higher in dogs with cancer than in healthy dogs. However, there is a great amount of overlap in levels measured from healthy dogs, dogs with cancer, and dogs with other diseases. Meaning that even dogs previously diagnosed with cancer can have normal serum TK levels.

TK levels have also been measured in cats and a reference interval was established from clinically healthy cats, cats diagnosed with lymphoma, and cats with inflammatory gastrointestinal disease. Cats with lymphoma had significantly higher serum thymidine kinase activity than healthy cats or cats with inflammatory disease and cats with non-hematopoietic neoplasia.

CRP is the major acute phase protein produced in response to inflammation and cytokine release. Serum CRP levels correlate to the duration and severity of inflammatory response. Causes of inflammation are varied, and include infection, autoimmune disease, and cancer. Therefore, CRP is considered a sensitive marker for inflammation, but unfortunately, it is relatively non-specific as to the nature of the inflammation it represents.

In dogs, CRP is elevated in at least some kinds of cancer, and serum levels are generally elevated in dogs with cancer compared to healthy dogs. As with TK, there is significant overlap between these two groups, and some dogs with cancer have normal serum CRP while some healthy patients have elevated serum CRP.

Dogs with lymphoma who are in remission, with only microscopically detectable cancer cells in their bodies, generally have lower CRP than dogs with measurable lymphoma. This places potential value on serum CRP levels as a marker for remission status and relapse of disease.

Additional research is necessary to determine the value of measuring parameters such as CRP or TK before veterinarians can routinely recommend these screening tests for every patient. Additionally, doctors must cautiously interpret the results of these tests, as information regarding the benefits and complications of instituting treatment at an earlier stage are unknown.

Lastly, if we are to consider implementing such tests, I suggest that owners should begin testing their pets at the earliest possible age, and test consistently throughout their lives, in order to establish the most adequate control values with which to compare to.

I absolutely understand why owners would wish for a simple lab test that could reassure them their dogs and cats are as inwardly healthy as they appear on the outside. I also understand the importance of early detection of disease and how this could lead to a more favorable long-term outcome for a pet.

However, I cannot ignore the sizeable gap of evidence-based information between these two poles regarding the utility of screening tests for cancer in companion animals that needs to be filled before veterinarians should be routinely recommend such diagnostics for their patients.

For more information on blood tests and cancer in pets see: Blood test for cancer in pets

I am supremely excited!

One of my articles was selected to be published on! This is a website created and founded by Dr. Kevin Pho, a human internist and health care social medial leader.

I’ve been a follower of the site for many months now, and thought maybe, just maybe, I could throw my hat into the ring and submit an article and see if they would consider publishing it. All of the articles are centered on human medicine, so I figured it was a complete and literal shot in the dark.

Imagine my surprise when Dr. Pho contacted me to let me know he selected my article to be posted on the site!

The Darker Side of Medicine was a popular post on my blog, which is obviously only a teeny tiny blip on the stratosphere of social media. The fact that a website dedicated to human medicine would consider including a piece written by a veterinarian is quite an honor. The idea that what I write about could be interesting to that broad of an audience is even more fascinating to me.

Here is the link to the article: The Darker Side of Being a Doctor on

The three step plan to curing cancer…

The 3-step mantra ingrained into my brain during my residency in medical oncology was to “name it, stage it, and treat it.”

The philosophy is simple: First you must identify the disease process you’re dealing with (name it). Then you search for where in the body you can find evidence of the disease (stage it). Then you decide on the most appropriate treatment regimen (treat it).

I would estimate that 95% of the cases I managed during those three years adhered to the strict 3-step guideline. There was an odd patient here or there where I didn’t have complete staging available, and an even stranger situation where I lacked a biopsy diagnosis to confirm a previously harbored suspicion. Cases were simply managed the “ideal” way because we could demand that it be done.

When I left the hallowed halls of my academic training at veterinary school and ventured out in to the “real world,” I held fast to my upbringing as an oncologist. I only wanted to see patients who were confirmed to have cancer, as my goal was to focus my energy on their treatment rather than the pesky tests attached to their disease.

I’m not sure when the shift started, but I know it was fairly soon after I began working on my own that I realized I may need to bend my previously inflexible rules about patient care.

In order for me to build a thriving veterinary oncology practice and to accommodate the needs of my referring veterinarian population and owners, I would need to be okay with seeing pets without a diagnosis, to become adept at picking and choosing tests based on an owner’s ability to pay, and in some cases, treat pets without knowing exactly what was going on in their bodies.

In the real world, primary care veterinarians exist on a continuum, from small town one-doctor practices lacking what most of us would consider “basic” tools, such as in-house laboratory equipment and x-ray machines, to large-scale 24 hour emergency facilities who perform all of their own medical and surgical procedures.

There are plenty of cases where a primary care veterinarian suspects a pet has cancer, but either is missing the appropriate diagnostic device necessary to confirm things, or is unsure of the appropriate test to order and wishes to spend their client’s money wisely. Those pets definitely deserve the benefit of referral to a facility where they can have those procedures performed. And that is where I can help.

My knowledge and narrow focus of experience is extremely valuable in helping to guide owners and make recommendations for the tests I think would be most appropriate. I can go over the pros and cons of each approach and select the best plan of action alongside an owner, which is extremely empowering for them. This openness of discussion can sometimes come with the price of feeling frustrated with those cases where a definitive diagnosis isn’t achieved.

This happens most frequently because an owner literally “puts the brakes” on the testing algorithm I’ve previously outlined. Owners are typically comfortable with the non-invasive assays, such as lab work, radiographs or ultrasound exams. Once I start speaking of “biopsies” or “aspirates,” or even “surgery,” my suggestions are met with resistance, as the perception is that they are then putting their pet through “too much.”

Other times, owners have followed each of my recommendations, but the samples I’ve obtained are diagnostically inadequate. Infrequently, I’ll receive a cytology or biopsy report offering up an interpretation of “malignant neoplasia” or “poorly differentiated tumor.”

All this tells me is that the pet has cancer. It doesn’t provide any additional information as to the exact tissue of origin, the type of cancer, the risk of spread, or how to treat it. Those conversations are often the most difficult to have with owners, and more than a few times I’ve shared in their frustration when they tell me they’ve “spent X amount of dollars at your hospital and you haven’t told me anything new.”

When I haven’t actually “named” the disease but am asked significant questions regarding prognosis or treatment options, or even what to expect as the disease progresses, it puts me in an incredibly challenging position. I am obligated to tell owners the next most appropriate step to get us the answer we are looking for. But this can be met with significant resistance.

More frequently, I am expected to use my experience and instinct to make generalizations about outcome, even though that’s an impossible task to undertake. It is then that I find communication to be the key towards making sure everyone is on the same page regarding expectations, limitations, and potential outcomes.

There are times when I’ve moved directly to step 3 of my residency mantra without adequately and appropriately completing steps 1 and 2. I don’t enjoy knowing I’m doing nothing other than an elaborate and educated form of guessing when I prescribe a plan without a diagnosis. I also really hate envisioning my mentor’s thoughts about my actions.

Ultimately, as long as I know I’m doing the right thing for my patient, I’m content with mixing up the order of things from time to time.

I’ll admit, it’s a pretty great feeling when a sick patient gets better based on my intuition alone.