Bladder Cancer In Dogs
Bladder cancer is an aggressive cancer that often spreads to other parts of a dog’s body. Although there are multiple options for treating canine bladder cancer, it cannot be cured. It typically strikes dogs age 10 or older and is more common in females. Any breed can develop bladder cancer, but Scottish terriers and Shelties (Shetland sheepdogs) have a higher chance of being stricken. Typical symptoms include blood in the urine, multiple urinary tract infections (UTIs) and other urinary issues.
Types of Bladder Cancer and Metastatic Disease Potential
Transitional cell carcinoma and leiomyosarcomas are two types of bladder cancer in dogs. Transitional cell carcinoma is the most common, representing 90% to 95% of all bladder tumors. These tumors develop in the transitional epithelial tissue (the bladder lining). Leiomyosarcomas arise from smooth muscle tissue, also found in the bladder wall. Bladder cancer can metastasize (spread) to the lymph nodes, lungs and liver. As the mass grows, it can crawl up toward the kidneys via the ureters or can grow down into the urethra. If the dog is male, this type of cancer can affect the prostate, as well. In the latter stages of bladder cancer, it can spread to the lungs. An uncommon though benign bladder mass, called a polyp, should also be considered when working up a patient for bladder cancer.
Clinical Signs to Look for
Not surprising, many of the clinical signs of bladder cancer in dogs involve urinary issues. Hematuria (blood in the urine) is a scary and obvious sign that something’s wrong, but it isn’t necessarily cancer. Hematuria could also be a symptom of a bladder infection or bladder stones. Other signs include your dog straining to urinate, having repeated UTIs or having frequent small urinary incidents. Sometimes, your dog may urinate in a trickle instead of a stream, because a bladder tumor in dogs can grow over the “doorway” to the urethra. In that case, one way to treat the symptom (but not the cancer) is to place a stent to keep the passageway open.
It’s critical to know that it’s considered a medical emergency if a dog is unable to urinate. If your dog is experiencing any of these symptoms, always watch carefully and bring the dog to your veterinarian or an emergency clinic if he or she cannot urinate.
Your dog also may be lethargic, or struggle to lie down or stand back up, as the mass can cause pelvic discomfort.
Many of the symptoms of bladder cancer can also be signs of a bladder infection or a urinary tract infection, so a thorough diagnosis by a veterinarian is critical. Bladder stones are another possibility for these clinical signs. The workup may include bloodwork, urinalysis and a urine culture. An abdominal ultrasound is preferable to abdominal X-rays. Other possibilities include a CT scan, and a biopsy or aspiration. Chest X-rays may be ordered to determine whether the cancer has metastasized.
Treatment Options and Prognosis
There are numerous options for treating a dog with bladder cancer. The course of treatment depends on whether the cancer has spread, and if it has, to where it has spread.
Surgery: If the cancer is in the apex of the bladder, surgery can be performed to remove the mass and attempt to obtain clean margins. However, even if margins are determined to be clean, tumors can recur or metastasize in about a year.
Chemotherapy: If a tumor cannot be surgically removed or if you decline surgery for your dog for another reason, chemotherapy (as an intravenous injection or as a pill) is another option. This might require weekly hospital visits for three or four weeks. Depending on the protocol, chemotherapy has a 40% to 70% chance of shrinking the tumor or slowing its growth. Chemotherapy helps dogs with bladder cancer for between six and 12 months on average.
Stereotactic Radiation: Stereotactic Radiation is a newer form of treatment for dogs with bladder cancer. This typically requires just 1-3 treatments. There are fewer side effects than chemotherapy, and veterinary oncologists are seeing good results. A dog that undergoes Stereotactic Radiation may still have blood in its urine as the tumor dies. The dog’s skin may also be affected, similar to a sunburn, but that typically will resolve within a couple of weeks. It’s also possible that hair will not grow back on the part of the abdomen that was in the radiation field. If the intestines are in that field, the dog could have diarrhea for a few weeks from the radiation, as well. The team at PetCure Oncology is qualified to provide Stereotactic Radiation as well as supportive care in the event that these side effects develop. This innovative treatment aims to damage the tumor without harming surrounding tissues and organs. With bladder cancer, the treatment protocol may call for following radiation with chemotherapy.
Drug treatment: Drugs are also used to treat transitional cell carcinoma in dogs. One such drug is piroxicam (also known by the brand name Feldene), a non-steroidal anti-inflammatory drug (NSAID) that has anti-cancer properties specifically against transitional cell carcinoma in the bladder. The use of piroxicam has been studied for decades at Purdue University. In one study conducted by the Purdue Comparative Oncology Program, 62 dogs with transitional cell carcinoma were treated with piroxicam. In 44 of those dogs, the tumor either remained stable or decreased in size, and the tumor went into remission in two other dogs. Dogs treated with piroxicam survived 195 days on average. In another study by the same program that used a combination of piroxicam and chemotherapy, a 35% remission rate was achieved.
A dog’s kidneys must be functioning well before piroxicam can be safely used. Because cancer can eventually affect the kidneys, bloodwork is indicated periodically to check kidney enzymes and function. In a small percentage of dogs, piroxicam also can cause GI upset.
Other non-steroidal drugs such as Rimadyl (Carprofen) may also be used to treat this type of cancer.
No treatment: If the decision is made to not pursue treatment, all of the symptoms can worsen and the dog’s appetite may eventually decrease, leading to weight loss. Important to note, however, is that weight loss can occur despite a normal appetite — that is the cancer’s affect on the body. Bladder cancer usually progresses in a matter of months and life expectancy does not extend beyond that.
Find a PetCure Oncology Location Near You
PetCure Oncology provides the most advanced and innovative treatment options available for dogs with bladder cancer and other types of cancer. We are supportive, professional and caring and our mission is to prolong your pet’s life and maintain quality of life as long as possible.
For more information about PetCure Oncology and our innovative treatment options, find a location near you today.