Ask the Vet: Meet Rex
Meet Rex. Some of you may be familiar with him as he was often the subject in the Point Arena Peddler. He is a beloved, exuberant, twelve-year-old male, neutered, yellow labrador, and was a long-time resident of the Mendocino Coast now living in Atlanta, Georgia. Recently he had an episode where his owner found him outside, trembling, disoriented, unable to stand, and with a very uncomfortable belly. He was taken to his veterinarian, and his owner got the devastating news that Rexie has cancer, specifically, a type of cancer called hemangiosarcoma.
Hemangiosarcoma is a malignant tumor of cells lining blood vessels. In theory, hemangiosarcoma can develop anywhere that there are blood vessels, but the most common sites are the skin, spleen, and heart. It is a common cancer in middle-aged to geriatric dogs, accounting for approximately 5% of all cancer cases, and can also occur in cats. It is most common in large breed dogs, predominantly German Shepards, Labradors, and Golden Retrievers.
The skin form often looks like small blood blisters. These small tumors usually arise from sun exposure and therefore tend to develop on sparselyhaired skin. Pets that love to soak up the sun while lying on their backs can develop many of these tumors. Prompt removal is very important as it is often curative by stopping the tumors from spreading under the skin.
Hemangiosarcoma of the spleen is most often seen at our clinic and what Rex was diagnosed with. The spleen resides deep within the abdomen, predominately on the left side. Unfortunately, because of the location of the spleen, the tumor can grow quite large and go completely unnoticed by an owner until it starts to bleed internally. Whether benign or malignant, tumors in the spleen often break open and bleed profusely, which can be life-threatening. Usually, there is a smaller, acute bleed where the dog experiences a period of pale gums, weakness, and disorientation resolving when the bleed stops. These “episodes” are often the first sign where an owner might notice that something is wrong with their pet and bring them in for a check-up.
Initial diagnosis of a splenic tumor involves blood work, x-rays, and ultrasound. Because these tumors often bleed, these dogs are usually anemic or have a low number of red blood cells. Xrays and ultrasound are performed to identify the presence of the tumor in the spleen, and the ultrasound will also look for spread to other organs, such as the liver. Once the splenic tumor is confirmed, chest x-rays are also performed to look for metastasis.
Approximately 40% of splenic tumors are benign, and 60% are hemangiosarcomas. It is not always possible to tell before removing the spleen whether it is cancerous or not, but unfortunately, other than surgery, and treatment options are limited. Dogs with hemangiosarcoma usually only live one to three months post-surgery and possibly six months with surgery and chemotherapy. If the tumor is benign, surgery is curative. When there is a strong suspicion that the splenic tumor is hemangiosarcoma, owners will often opt out of surgery and try to keep their pets as comfortable as possible, as is the case with Rex.
Yunnan, a Chinese herb whose actual formulation is a long-held secret, has recently become a helpful tool for dogs with hemangiosarcoma. It has been shown to improve clotting, which can be very helpful with the tendency of splenic tumors to bleed and clot repetitively periodically. Sadly, the dog will eventually have a bleed too big for Yunnan to stop, but it is still a valuable option for extending their lives for several months.
Heart-based hemangiosarcoma is the other form of this cancer, where the tumor grows at the base of the right side of the heart. As is typical with this cancer, the tumor has a tendency to bleed with catastrophic results. Over 50% of the time, it has already spread to other areas by the time it is diagnosed.
Because these tumors can develop without any initial symptoms, regular, thorough exams of our middle-aged to geriatric pets are important. Needless to say, splenic hemangiosarcoma was a devastating diagnosis for Mr. Rex, but as is often the case with our pets, he carries on being happy and loving in his day-today life. His owner knows that sometime soon, she will lose her very best companion to this cancer, but until then, she is going to give him the best and most comfortable life that she can.