Where to Draw the Line When a Pet is Suffering from Cancer
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?
