When Your Vet's Diagnosis Disagrees With Reality

Joanne Lynn Intile, DVM, MS, DACVIM
Published: January 30, 2014
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Owners typically seek consultation with a veterinary oncologist for one of three reasons:

  1. They are interested in obtaining a definitive diagnosis and performing recommended staging tests to establish options for further care.
  2. They have a solid understanding of their pets’ diagnosis and are definitely interested in treating their pet’s cancer.
  3. They are searching for more information about their pet’s diagnosis and are interested in knowing what can be expected as the cancer progresses.

Naturally, there is a great deal of overlap between the different motives, but central to each is learning what their pets’ prognosis will be.

Though most of us associate the word prognosis with survival time, the actual definition of the word is “the likely course of a disease or ailment.” Obviously, the latter description encompasses much more complicated aspects than simply how long a pet will live.

The behavior of some cancers is fairly predictable. Pets with lymphoma tend to become extremely ill as the disease progresses. Dogs with hemangiosarcoma will typically experience a massive bleeding episode, and cats with oral squamous cell carcinomas usually stop eating from pain directly related to the tumor. Though I’m confident in my ability to foresee what will happen in those cases, it’s very difficult to pinpoint the exact time frame when the illness, bleeding, or anorexia will be fatal.


I recently read an article describing the imprecision of human physicians with regard to their ability to provide a prognosis for terminally ill patients. Intrigued by the topic, I delved deeper and discovered there are actually dozens of research studies centered on examining doctors’ accuracy when it comes to predicting how long terminally ill patients would survive following a diagnosis.

Turns out doctors are typically terrible at the task. Surprisingly, physicians tended to overestimate the prognosis, meaning they believed and consistently told their patients that they would live longer than they actually did. Moreover, the lengthier the doctor-patient relationship, the less accurate the prognosis tended to be, leading to the conclusion that “disinterested doctors . . . may give more accurate prognoses, perhaps because they have less personal investment in the outcome.”

Depending on the study, results did not matter if the doctor giving the news was a general practitioner or a specialist. Positivity appears to have zero correlation with experience or level of post-doctoral training and specialization. When considering why human physicians would overestimate prognosis for terminally ill patients, I started wondering, what are the inherent personality traits responsible for such optimism, especially in light of my experiences managing patients with terminal diseases?

Do we overestimate how we think our patients will do because of our inherent drive to heal and relieve suffering, so much so that we are willing to put aside our book knowledge and sustain ourselves on chance? Are we so driven to succeed that anything less than remission, even in patients we know have advanced disease, would be considered failure?

If we offer a more conservative estimate for outcome, would an owner be more inclined to pursue aggressive care for their pet? Since quality of life for their pets is the main concern for most people, and in the “real world” we have to consider the unfortunate “cost to benefit” ratio, is it possible we skew towards optimism because of our hope for a chance to cure?

Do we wish so strongly to maintain a partnership with our owners and their pets that we subconsciously avoid the conflict that arises out of complicated discussions about end of life care and how rapidly the disease could progress?

I'm sure when it comes to prognosis, most pet owners would appreciate complete and brutal honesty, even if this would mean shocking them with how little time they may have left with their beloved companions. I can count on one hand the number of times an owner said, “I don’t want to hear the numbers,” meaning they are unwilling or unable to listen to what I think could be a realistic outcome for their pet. Typically I see this arise from apprehension or denial rather than remarkable optimism for their pet’s outcome.

From my perspective, it isn’t easy to discuss a prognosis with owners. I never want to deliver bad news, and though my skin is thicker than it was a few years ago when I was an intern having such discussions for the first time, I’m never completely comfortable “guessing” what I think could happen to their pets and in what time frame it could occur.

An accurate prognosis can only be derived from the results of clinical studies examining hundreds, if not thousands, of patients with the disease. A clinician’s experience may temper such academic information and tailor the answer more specifically for the patient in question.

In reality, the prognosis we offer may stem at least partly from a deeper part of our professional soul; a part designed to protect our ideals of healing and helping as we hold out for the hope of a cure, even when the statistics tell us otherwise.

Dr. Joanne Intile

Image: Thinkstock