Lymphoma in cats: what is it, and how is it treated?

I recently learned that Instagram celebri-cat Mr. White the Coffee Cat (a.k.a. Coffee) has been diagnosed with lymphoma. He’s not the only cat I’ve known to have lymphoma: My sweet Dahlia died from atypical large-cell lymphoma, and a good friend of mine had an FIV-positive elder kitty who developed lymphoma as well.

Because the word “cancer” can be terrifying whether it applies to you or your cat who receives the diagnosis, I spoke to Dr. Avenelle I. Turner, DVM, DACVIM, medical oncology, also known as Dr. Avey, the senior board certified veterinary medical oncologist and lead investigator for clinical trials at Veterinary Cancer Group in Los Angeles. I wanted to get the facts about lymphoma, its symptoms, treatment, and prognosis.

The facts

Lymphoma is the most common type of cancer seen in cats. It develops from white blood cells called lymphocytes. It’s considered a “fluid tumor” because it’s a blood cell-derived disease, unlike solid tumors that begin in the tissues of the body.

There are two types of lymphoma — large-cell lymphoma and small-cell lymphoma. Large-cell lymphoma is considered a high-grade disease that develops quickly, usually within four to six weeks. Small-cell lymphoma is considered a low-grade disease, with symptoms that develop more slowly, perhaps over several months.

Risk factors

The biggest risk factor for lymphoma is age. Cats who develop small-cell lymphoma tend to be age 10 or older, while cats who develop large-cell lymphoma tend to be 8 to 9 years old.

Another risk factor is being positive for feline immunodeficiency virus or feline leukemia virus.

Because age is a primary risk factor, there’s no way to actively prevent lymphoma, but early detection will provide the best chance at recovery and remission.

Early warning signs

Because lymphoma typically involves the gastrointestinal tract, the early symptoms of lymphoma are pretty non-specific and include frequent vomiting and changes in stool, usually diarrhea.

“A lot of cat owners think vomiting is normal, but if your cat is vomiting once a week or more, it’s not normal,” says Dr. Avey. “With low-grade lymphomas, I typically see a history of at least six months of regular vomiting.”

Other symptoms include weight and appetite loss.

Treatment options

“Probably the most common treatment is steroids,” says Dr. Avey. “It make them comfortable for a period of time — a few weeks with high-grade tumors and a few months with low-grade tumors.”

Chemotherapy is used to treat cats with lymphoma, often in combination with steroids. Radiation therapy is rare, but it is occasionally used to treat location-specific tumors such as mediastinal (inside the chest wall behind the breast bone) or nasal lymphoma.

Some people worry about putting their cats through chemotherapy, especially if they’ve known people who went through cancer treatment. But, says Dr. Avey, “the symptoms of lymphoma are much more dramatic than the side effects of the chemo.”

Cats don’t lose their hair, although their whiskers do get brittle and can break off. Their fur gets softer and they shed a bit more: It appears that the topcoat may fall out but the soft undercoat grows better. Cats’ appetite or food preferences might change during the course of treatment, perhaps because food tastes different than it did before chemotherapy. If your cat is undergoing chemo and he’s not eating his regular food, try different brands and flavors and ask your vet for an appetite-stimulating medication.

Prognosis

The prognosis for lymphoma is generally pretty good- a majority of cats are at least going to respond to treatment.

“In small-cell lymphoma, we strive more for resolution of symptoms than anything else,” say Dr. Avey. “We can’t necessarily call it a remission because there are permanent changes in the gut: The intestinal lining gets thicker and lymph nodes may always be enlarged.”

With large-cell lymphoma, about 25 percent of cats get a complete response to treatment while around 50 percent of cats get a partial remission. Unfortunately, about 25 percent of cats are just not going to respond to treatment.

“We know very soon — within the first few weeks — whether or not a cat is responding to treatment,” says Dr. Avey. “You tend to know the responder sooner than the non-responder.”

When a cat with lymphoma does go into remission, the general timeline is about nine to 12 months with intestinal lymphoma, but remission of nasal and stomach lymphoma tends to be more permanent.

“You don’t get those numbers unless you try,” says Dr. Avey. “And during the time of remission, cats enjoy a good quality of life.”

Some cats achieve much longer remissions: One of Dr. Avey’s patients, Rambow, has been cancer-free for seven years, and another was in remission for nine years before he relapsed.

“I tell those stories but I don’t promise to get remissions that long because they aren’t typical, but they can happen,” she says.

Lymphoma is a treatable cancer, particularly when it’s detected early. Cats don’t suffer the way humans do with chemotherapy, and your cat can achieve a good quality of life for the length of his remission, no matter how long or short that is. We wish Coffee and his family the best as they go through this tough time, and we sure hope he gets one of those miracle remissions Dr. Avey mentioned.