Vail Pet Talk column: Don’t watch growths on your pet grow
Size matters when it comes to soft-tissue tumors on your dog or cat. For that reason, the common advice by many professionals to “just watch it” regarding soft-tissue tumors needs to have a caveat: Don’t watch it grow or simply remove it ASAP.
We have been seeing an inexplicable increase in the number of soft-tissue tumors called soft-tissue sarcomas in the past 12 months. Soft-tissue sarcomas comprise about 15 percent of all subcutaneous (i.e. under the skin) tumors seen in pets, and interestingly, this is about five times as many as are seen in humans. Usually we see close parallels, but these sarcomas offer a unique example where our clinical experiences and research can help humans.
Soft-tissue sarcomas arise from connective tissue; examples are fibrous tissue, nerve sheathes or covering, fascia (the thin membrane wrapping muscle), fat, muscle, lymph tissue, spleen and tiny blood vessels. They are a very unpredictable group of tumors and tend to reoccur locally but can also metastasize or spread to other organs. A lot of this depends on the initial organ and pathologic grade of the tumor. We will get to this in a minute.
DECIDING WHETHER TO REMOVE IT
The first thing you should do with any lump or bump is get it checked out by your veterinarian. Veterinary medicine moves at a much quicker pace than human medicine. In the office, your skilled veterinarian will likely do an aspiration biopsy, which means inserting a small needle and sucking up some cells and then injecting them onto a slide.
Then it is off to one of your veterinarian’s favorite places — no, not the brewpub, but rather his or her microscope. We will take a peak to see if the cells are cancerous or not.
The “Johns Hopkins” approach may be to send the slides off to a board-certified pathologist, but most of us in the field are much more pragmatic and, in an effort to save our clients time and money, are confident enough knowing if a growth needs to come off or not.
EVALUATING THE TUMOR
Once removed, we will then send the entire tumor (unless it is too large to be sent in whole) to a pathologist to be evaluated. This is a very important step. My favorite oncologist says about the pathology report, “If it is worth taking off, it is worth sending off.” A pathology report is money well spent.
The pathologist, aka the smartest doctor in the room, will let us know not only what type of tumor, but also will tell us things like if we successfully removed the entire tumor (i.e. have clean margins). They will also tell us very important information about whether it is malignant (cancerous) or benign (noncancerous), as well as just how malignant the tumor is. This is called grading and the grades for soft-tissue sarcomas are usually low or 1, medium or 2 and high or 3. High grades here are not a good thing. We will also get much more technical info about the tumor that is beyond the scope of this article but equally important.
The information from the pathologist will let us know how to proceed and whether or not we need to “stage” the cancer. Staging involves determining how far or if the cancer has spread. In a typical office, this entails taking abdominal and chest radiographs, biopsies of nearby enlarged lymph nodes and often ultrasound.
CREATING A GAME PLAN
Once we gather all of the information, we can together develop a game plan. Often with soft-tissue sarcomas, this leads to a discussion about chemotherapy, radiation therapy or both. We also will talk about nutritional and supplement changes. Think low-carb diet, fish oils, antioxidants, green tea and mushroom extracts.
So, back to this size thing. It seems that 3 centimeters, or about 1.25 inches, seems to be a critical size. Tumors smaller than this cutoff size carry a much better prognosis. This is likely due to the fact that a smaller tumor is more likely to be completely removed and also a smaller tumor has probably had less time to metastasize. Some soft-tissue sarcomas can be very difficult to fully remove, even if they have a capsule around them (think grape skin). This is because they often have microscopic finger projections outside what we can see. It only takes one cancer cell remaining for this to reoccur.
Here is the good news/bad news with soft-tissue sarcomas. Low-grade ones do very well and the five-year survival rate is excellent. High-grade 3 tumors do not do well and often metastasize. The numbers are stunning; often within six months we lose the battle. It is still hard for me, after all these years of practice, to tell someone that a 1½-inch seemingly harmless bump under the skin may kill a pet in six months. So get these things checked out early. OK?
Stephen Sheldon, DVM, a member of The Veterinary Cancer Society, practices at Gypsum Animal Hospital. He can be reached at 970-524-3647 and firstname.lastname@example.org or through the website http://www.gypsumah.com.