The good thing about science is…

While recently searching for information on the role of evidence-based information in medical decision-making, I came across the following quote by Neil DeGrasse Tyson:

“The good thing about science is that it’s true whether or not you believe in it.”

My initial impression of the statement was one of complete agreement. I approach both my professional and personal life with fairly rigid factual standards, constantly searching for proof and examining probability with regard to making important decisions or tackling difficulties.

With further consideration, I wondered how well the assertion actually holds up in the “real” world. Human nature imparts a desperate need to make sense of the things we don’t understand. It would be wonderful if everything we did could be categorically isolated into true or false statements. But reality dictates this is rarely ever the case.

We frequently encounter something we lack sufficient knowledge or information about. When we do, we use a combination of education and experience in our struggle to comprehend the unknown. This becomes particularly pronounced when we lack scientific comprehension of a particular topic and we allow experience to be the major contributor to our knowledge. When this occurs, we are participating in what is known as “conformation bias.”

Conformation bias occurs when we search for or interpret information in a way that confirms one’s preconceptions. Phrases such as “I believe,” “I think,” “this makes sense to me,” or “it’s logical that…” typically precede statements raft with conformation bias.

As an example, nearly every canine patient I see wears a collar. Many of the canine patients I see also have lymphoma. I might therefore conclude that collars were a cause of lymphoma in dogs. As I’m unaware of any research study designed to examine the presence of a collar as an independent risk factor for developing cancer in dogs, my assertion would be made from conformation bias, rather than scientific basis.

Unfortunately, those lacking a strong command of medical terminology and principles of physiology can be targets for slick marketing techniques, especially in relation to issues relating to their health or the health of their pets.

I think of this every time I come across a new product claiming to “detoxify the body,” or “cleanse the system,” or “boost the immune system.” My scientific mind knows those phrases are absolutely meaningless. I know my liver and kidneys already do all the detoxifying and cleansing that I need. I know if my immune system were to be boosted, it would probably start furiously attacking my own cells.

I also struggle because I know scientific discovery is borne out of questioning unproven observations and ideas. What we know as being scientifically true was, at one point, unknown. And even scientifically proven concepts can be refuted with additional study.

Every research project I’ve been a part of was derived from abstract concepts and experience and thought. They were designed to question whether the observations precipitating the study occurred via pure chance or from evidence based information. Of course scientific reasoning played the biggest role in actual design of the study, but an inquiring mind was responsible for thinking of initial hypothesis.

Statistics are our barometer for assessing the validity of a theory. When statistics show significance, we accept the hypothesis as truth. If significance is not achieved, it is rejected and considered scientifically false.

Experience tells me that accepting statistical significance or insignificance isn’t always the most accurate path to follow. Statistics can be manipulated and studies can be flawed. Remarkable conclusions can be drawn off of extremely small sample sizes or curiously designed studies. I also value my experience and how important it is in making decisions about my patients—even when no evidence-based data exists to prove that my theory is correct.

Is science true whether you believe it or not? It’s an interesting question to ponder, even for this scientist.

When cancer hurts, but only part of the time…

People readily associate a diagnosis of cancer with severe adverse clinical signs. I’m not speaking of the effects of chemotherapy or radiation; rather I’m referring to the decline in a patient’s quality of life occurring secondary to progression of disease.

Regardless of whether the patient is a human or an animal, we’re equally capable of visualizing a person or pet experiencing vomiting, diarrhea, inappetance or lethargy directly because of a diagnosis of cancer.

As a veterinary oncologist, my responsibility is to guide owners in deciding whether to pursue treatment versus palliative (comfort) care versus euthanasia following a diagnosis of cancer. Those conversations are difficult, but can be a bit more straightforward in cases where pets are obviously sick from disease, versus when they are diagnosed incidentally or with minimal signs.

When an animal’s quality of life is poor and is manifested by major symptoms such as weight loss, lethargy, or breathing difficulties, it’s not difficult to explain to an owner that their options are limited and heroic measures are not in their pet’s best interests. With rare exception, such poor quality of life is considered an absolute “endpoint” for pet owners.

However, pets with locally advanced forms of cancer, rather than systemic disease, are more likely to only sporadically show dramatic adverse signs from their condition, rather than constantly behave sick or painful. For those patients, the line in the sand of “good versus bad” health is blurred. It’s challenging to discuss the profound impact a temporary, but consistent, deterioration in behavior has for a pet.

The best examples of such tumors are those affecting the urinary bladder and perianal/rectal regions. The most common tumors of the urinary tract include transitional cell carcinoma, leiomyosarcoma, lymphoma, and squamous cell carcinoma. The most common tumors of the perianal/rectal region include anal sac adenocarcinoma, perianal gland adenomas and adenocarcinomas, rectal carcinoma, and lymphoma.

Cancers arising from these specific anatomical areas do not cause the typical, systemic signs of illness mentioned above, at least in their early stages. However, tumors of the urinary bladder can obstruct the flow of urine out of the bladder. Likewise, tumors of the perianal region are significant because they can inhibit the pet’s ability to pass fecal waste.

Tumor growth within the urinary bladder or perirectal/perianal region causes signs such as straining to urinate or pain and difficulty while passing stool. When tumors are small, signs are usually subtle and occur only a few times per week. Over time (weeks to months), signs progress to include more extreme discomfort when attempting to eliminate urine or feces on a regular basis.

During the specific time period the pet is attempting to void, I know their quality of life is exceptionally poor. The pain associated with elimination, though intermittent, drastically impacts their lives. However, at other times, affected animals will eat, drink, sleep, play, beg for treats, and wag their tails in the same way they would prior to their diagnosis of cancer. They don’t look sick, but are they truly healthy?

Owners struggle with assessing quality of life in those situations. The temporary, but intensely negative impact makes answering the question of “How will I know when it’s time?” so much more fluid. The conversations are complex. The answer lies in the gray area between the extremes of health and illness.

We never consider cancer a “good” diagnosis to face. We associate the word “cancer” with swiftly growing tumors that spread rapidly throughout the body, leading to a patient’s hasty demise.

Unfortunately, tumors located in a place where their presence interrupts vital processes necessary for survival may never need to travel farther than their anatomical site of inception to cause equally devastating effects.

Pet owners and veterinarians bear tremendous responsibility in ensuring that the needs of animals affected by any type of cancer are met. Even if symptoms occur intermittently, we must remember that quality of life is measured both quantitatively and qualitatively. Are we truly keeping an animal’s quality of life at the forefront of our decision making if we allow suffering to occur?

You never forget your first…

His name was Ali, as in Mohammed Ali. He was a handsome 1½-year-old tan and white Boxer with a sweet and playful disposition and a ton of energy crammed into the tiny makeshift exam room. Though Ali was only one of dozens of dogs evaluated at the Southside Healthy Pet clinic that evening, I’d forever remember him as the most exceptional dog I’d ever met, because Ali was the first “real patient” of my veterinary career.

The Southside Clinic was a veterinary student run “well pet” clinic offering low-cost exams, vaccines, and preventative medicine to pet owners demonstrating financial need in the community my veterinary school resided in. Ali’s owner brought him in for a recheck examination and booster vaccines, and on that particular evening, I was entrusted to obtain his history and perform a physical to assess whether Ali was healthy enough to receive his scheduled vaccinations.

As I began my systematic approach to his exam, I experienced the same anxiety I’d encountered during the times my mind blanked while answering routine questions on a final when I was sure I’d known the correct choices not more than ten minutes prior.

I’d previously practiced performing physicals numerous times; on my own pets, the friendly dogs and cats from the local shelters, and on my colleagues’ critters. But the challenge of doing the same task on an actual patient with an actual owner holding the other end of the leash was an entirely new experience for me.

I felt unprepared and ill-equipped for the task. I was sure I would forget to examine some crucial aspect of a critical body system. I worried I would miss a heart murmur or an abdominal mass or lameness.

I was paired up with a second year student who restrained Ali while I struggled to complete my tasks in an awkward and completely non-systematic fashion. Fortunately, both the dog and the student were exceedingly patient with my clumsiness and I was grateful for my partner’s assistance in reminding me of the things I should be looking for.

Ali’s exam was rather unremarkable (a term that, when applied to a medical record, denotes signs of health rather than implied mediocrity), but I’d discovered some sores and redness along the skin between his toes. The lesions weren’t noted during his exam the previous month, but the senior student had noticed similar red “bumps” between Ali’s shoulder blades during that previous visit. Those lesions had since resolved, but given the appearance of dermatologic changes in two distant anatomical locations, I wondered if unremarkable wasn’t the best term to describe Ali’s status.

But what was I supposed to do about it?

I consulted with the senior student, who made a suggestion based on her knowledge, but I wasn’t confident that it was the correct plan for Ali. The two of us spoke with the veterinarian supervising the clinic and he presented several potential diagnostic and therapeutic options for me to consider. Together, we discussed the pros and cons to each approach. I listened attentively, eager for instructions on how to proceed. More than a few moments of awkward silence passed before I realized I wasn’t going to be told what to do next.

Those passing seconds are etched in my mind, as they represented the first time I was treated more as a doctor and less as a veterinary student. The shift in responsibility lacked fanfare, but was palpable nonetheless. I’d need to stop thinking of myself as a task-oriented individual. I would need to learn how to become comfortable with taking charge of my patients’ care.

I quickly learned that the point of this clinic was not to be perfect, but rather to apply my flawed skills and imperfect knowledge in a “real world” setting. This was the time to make mistakes because I had backup available during every step of the process.

I reentered the exam room with increased bravado and assuredly discussed my findings and recommendations with Ali’s owner. I drew confidence from the reserve supplied by the staff veterinarian and his surety in my capabilities. A plan was set into action based on my conclusion as a primary caregiver rather than an intermediary whose role is to enact orders from someone else.

Looking back, Ali’s case was a bit of a no-brainer, but for a “first veterinary patient” I’m still inspired by the experience and what it represented for me in my educational process. I’d only been a veterinary student for three months, but I’d already begun the subtle process of transforming myself into a doctor.

Patients such as Ali made that transition all the more wonderful each time I encountered them.

I can’t take all the credit…

Have you ever heard of laparoscopic (minimally invasive) surgery? Here’s a great article written by my husband, Dr. Marc Hirshenson, on this interesting topic!

http://veterinarynews.dvm360.com/surgery-stat-finer-points-laparoscopic-liver-biopsies

Brain tumors in dogs and cats

One of the less common cancers I’m asked to consult on are brain tumors. Though such tumors occur with fair frequency in both cats and dogs, optimal diagnostic and treatment plans are not well established. Thus brain tumors are considered a challenging disease for both veterinary neurologists and oncologists.

Brain tumors are either primary or secondary, with about equal chance of either of them being the diagnosis. Primary brain tumors originate from cells normally found within the brain tissue itself, or the thin membranes lining its surface. The most common primary tumors are meningiomas, astrocytomas, oligodendrogliomas, choroid plexus tumours, central nervous system (CNS) lymphoma, glioblastoma, histiocytic sarcomas, and ependymomas.

Secondary brain tumors occur when either a primary tumor located elsewhere in the body spreads to the brain (a process known as metastasis) or extends into the brain via invasion from adjacent tissue (e.g., bones of the skull, nasal cavity, eye, etc.).

Brain tumors occur most often in older pets, with the median age of affected dogs and cats being 9 and 11 years, respectively. Certain breeds show a predisposition for developing primary brain tumors: Boxers, Golden retrievers, and domestic shorthair cats are at increased risk.

Brain tumors that originate from the membranes covering the brain (known as meningiomas) occur more often in dolichocephalic breeds—those with long heads and noses—such as Collies. Conversely, brachycephalic breeds, with their short-nosed, flat-faced appearance, are more likely to develop gliomas, which are tumors of the interstitial tissue of the central nervous system.

The most common clinical sign of a brain tumor in dogs is seizures. Cats are more likely to show a sudden onset of aggression. Other signs suggestive of a brain tumor include behavioral changes, altered consciousness, hypersensitivity to pain or touch in the neck area, vision problems, propulsive circling motions, uncoordinated movement, and a “drunken,” unsteady gait. Non-specific signs such as loss of appetite, lethargy, and inappropriate urination are also seen.

There are several recommended staging tests for pets suspected to have brain tumors. These tests are designed to examine for widespread disease in the body, are considered part of a general health screen, and can establish baseline information with which we can compare to in the future.

Staging tests include complete blood count (CBC), chemistry panel, thoracic radiographs, and abdominal ultrasonography. These tests are used rule out an extracranial primary tumor that has metastasized to the brain, or the possibility of another primary tumor located in a distant site. These tests provide owners with peace of mind for moving forward with advanced imaging (MRI/CT) of their pets’ brains. In approximately 8% of cases, results from such tests will ultimately lead to a change in the anticipated diagnostic and treatment plan.

When a brain tumor is suspected, and staging tests are considered clear, the recommended next test is typically magnetic resonance imaging (MRI). The exception would be cases where a pituitary tumor is suspected, as these tumors are better visualized using CT scan.

The only way to definitively diagnose a brain tumor and determine its exact tissue of origin would be through biopsy. While it is ideal to have a diagnosis before proceeding with therapy, veterinarians often recommend treatment based on a presumptive diagnosis from the imaging characteristics of an intracranial mass This is due to the increased risk associated with the procedure and the negative impact the clinical signs seen in affected patients has on their overall quality of life.

There are three primary treatment options for dogs that have been diagnosed with brain tumors: surgery, radiation therapy, and chemotherapy. The objectives of such therapies are to or reduce the size of the tumor and to control secondary effects, such as fluid build-up in the brain. Surgery may be used to completely or partially remove tumors, while radiation therapy and chemotherapy may help shrink tumors or reduce the chance of regrowth following surgery. Medications are also often prescribed to manage the side effects of brain tumors, such as seizures.

The prognosis for dogs with brain tumors is considered guarded to fair. Survival times of 2-4 months are expected with supportive care alone, 6-12 months with surgery alone, 7-24 months with radiation therapy alone, 6 months to 3 years with surgery combined with radiation therapy, and 7-11 months with chemotherapy alone.

As is typical for many aspects of veterinary oncology, accurate prognostic information for cats with brain tumors is lacking.

If your veterinarian suspects your pet has a brain tumor, please consider seeking a consult with a board certified veterinary neurologist or oncologist in your area to understand your options for both diagnosis and treatment.

You can find more information at the website for the American College of Veterinary Internal Medicine.