An uncommon cancer
By Michelle Gerhard Jasny V.M.D.
Published: June 23, 2011
"I'm sure it's nothing, but I keep noticing a little blood in his water bowl," the woman said in a worried tone. "I just want you to check him over. He must have a cut in his mouth or something." The patient in question was an elderly cat named Smokey. "Let's take a look," I responded noncommittally, but with a familiar sinking feeling. Smokey had lost a little weight since I had seen him last but otherwise everything looked fine. Everything you could see on the outside, that is. I took a deep breath and opened his mouth, hoping to find a loose tooth or something equally benign. Smokey wiggled his tongue in protest as I pulled down on his lower jaw. Beneath his tongue, right at the base where it roots to the floor of the mouth, was a raw, red swelling, at least an inch in diameter. It was pushing Smokey's tongue up and to the side.
Oral masses are relatively uncommon in cats, but I'd seen plenty like this over the years. This location is called "sub-lingual," i.e. under the tongue, and there is little doubt about the diagnosis. "I'm afraid Smokey has a tumor under his tongue. It's probably a form of cancer called squamous cell carcinoma." Smokey's mother looked at me expectantly. "It's pretty nasty," I went on, "and at this location it's not very amenable to treatment." Smokey's mother continued to look at me hopefully.
There are many different types of masses that can occur in the oral cavity of dogs and cats. Masses may appear on the lips, gums, around the teeth, in the jaw, tonsils, tongue. Unless the mass protrudes externally or distorts the jaw, owners often do not notice these growths until the pet exhibits clinical signs such as drooling, bad breath, trouble eating or swallowing, weight loss, swollen lymph nodes, and bleeding.
"If you want to proceed with aggressive treatment," I said slowly, "we would need to take a biopsy and send it to a pathologist. That would require general anesthesia." Some oral tumors can be biopsied without sedation, like on a cat I saw last week with a small pedunculated growth on the inside of his lower lip. (Pedunculated means "on a stalk.") I nipped off the mass for biopsy right then and there using a hemostat and scissors. Bleeding was minimal. The procedure was painless. If it turns out to be malignant, further surgery might be indicated but if it is benign, we're all done.
Smokey's case was different. The area was not accessible and was likely to bleed a lot. To biopsy safely he would have to be asleep, with an endotracheal tube in place to prevent aspiration of blood in the event of hemorrhage. Was it worth the anesthetic risk, expense, and discomfort for the cat, considering that the odds were extremely high that this was squamous cell carcinoma?
That depends. It depends on the person, the pet, the disease. I always start by asking, "Will the answer change what we are going to do?" If Smokey's mom would consider surgery, radiation, or chemotherapy, then we should go ahead. If she was the kind of person who needs a definitive answer, even though she doesn't plan to do anything beyond palliative care, we should go ahead. But Smokey's mom had been through a similar situation once before. Her love for another pet had prompted her to take that cat to a specialist and have surgery for a possible lung tumor. It had been extremely difficult emotionally, not to mention the financial and logistical considerations, and the kitty had not survived. What should I advise now?
I thought of another cat I had seen the month before. Caspar was also an older cat and had presented for congested breathing. In his case, the growth was not sub-lingual but in the back of the mouth coming from the area of the left tonsil. It looked like squamous cell carcinoma. Two years previously, Caspar had been through a serious episode of gastrointestinal disease. Because he was not eating for an extended period of time, the internal medicine specialists had placed a feeding tube through his esophagus, so his mother could syringe feed him via the tube, keeping him alive for months until he was again able and willing to eat on his own. It had been an emotionally difficult ordeal, not to mention the financial and logistical considerations, but the kitty had survived. Now, however, the prognosis was far poorer.
In each case our dilemma was similar. There was a remote chance that the oral mass might be something other than malignant cancer. I have very rarely seen such oral lesions turn out to be benign growths, or treatable infections, or allergic reactions. In Caspar's case I wondered if there was any chance that this was a bizarre overgrowth of tissue from the site where the feeding tube had been placed. But for both cats there was no question that far and away the most likely diagnosis was squamous cell carcinoma (SCC).
"Can't you just remove it surgically?" Smokey's owner asked. "Not without removing most of his tongue," I sighed. Surgical removal is the initial treatment of choice for SCC, but usually by the time the tumors are detected, it is too late. Neither radiation nor chemotherapy has been found to be curative, although they are sometimes used in palliative ways to slow progression. Although SCC doesn't tend to spread to other parts of the body, the local tumors are so invasive and fast-growing that most animals are euthanized within two to six months due to poor quality of life. Even with treatment, less than ten percent survive a year. In Caspar's case, it might have been possible to "de-bulk" the mass but a CT scan would probably be needed to accurately determine the amount it had invaded surrounding tissue. Both cats would likely require feeding tubes post-surgically.
Caspar's mother was understandably struggling with her decision. We opted to first try injectable corticosteroids on the unlikely chance that this was an allergic reaction, and with oral antibiotics to treat any secondary bacterial infection. Caspar's quality of life continued to decline. The tumor was occluding his airway and he was struggling to breathe. Both he and his mother had been through so much, we agreed we couldn't fight the tide. Two weeks after first seeing the tumor, we gently ended his suffering.
Smokey's mother also was struggling with what path to take. I suggested she consult an oncologist and see what they had to say. When in doubt, it's always a good idea to get a second opinion, especially from a specialist. The oncologists concurred with our presumptive diagnosis. They discussed the options for biopsy, and staging the cancer with lymph node aspirates, bloodwork, and chest X-rays. They suggested that a surgically placed feeding tube might be in order soon, and confirmed the guarded prognosis.
Smokey's mom decided against further work-up but took the oncologists' advice concerning pain medication and antibiotics. They also suggested a medication called piroxicam that is sometimes used in the palliative care of several different kinds of cancer. Smokey's mom is now consulting with other veterinarians who do complementary medicine, such as herbal treatments. I hope she finds a magic potion. I hope someone somewhere finds a magic potion, as, for now, conventional medicine has little else to offer.
