If you had a cancerous lump you’d probably want to have it cut off. As long as we’re cutting it off, I suppose we might as well get it all, shouldn’t we? Makes sense to me… only… how do we know how much to cut off?
Everybody has rules to live by. Some are sensible, like "Don’t eat yellow snow" and some are questionable as to their utility, like "Never eat anything bigger than your head." Today’s rule is "If it’s important enough to cut it off, it’s important to find out what it is and whether you got it all."
If the lump is cancerous, then you want to cut a wide margin around it. Sometimes it looks like the lump has nice, obvious, well circumscribed borders. Sometimes it does. Other times, microscopic examination of the surrounding tissues shows little cancer cells creeping away into what looked like normal tissue to your naked eye. So, with a cancerous lump you need to go wide and deep. With mast cell tumors, the oncologists recommend that you take a 3cm margin all the way around, including deep. That means you cut an inch and a half BELOW the tumor, as well as all round it. That’s a 3-inch diameter hemisphere: think half a baseball. It’s a big crater of a wound that is hard to close up.
Of course, if the lump is NOT cancerous, you would really prefer that the surgeon not excavate some great crater around it. That will be a bigger, more painful wound. PLUS, if you don’t happen to be as fat as the rest of America, that inch and a half deep might be a chunk of muscle. Ouch!
So, what’s a mother to do? Sometimes you can just stick a needle in the lump, pull out some cells, identify them under the microscope and know how to proceed. Many times that doesn’t work, as the individual cells don’t tell you as much as a sample that shows how they are arranged, as well. Therefore, when we’ve got a lump that’s fast growing, or bleeding, or just generally nasty-looking, we cut it off and take a small margin of apparently normal tissue around it. Then the whole mess goes off to the pathologist.
The pathologist slices it up and examines the architecture and types of cells. She also looks at all the borders of normal tissue for evidence of cancerous cells. If the tumor is not an aggressive type, one that usually doesn’t spread much, and you have clean margins, you’re done. If it turns out to be benign and not cancerous, it’s all good. On the other hand, if you’ve got "dirty margins" (cancerous cells going out to the edge), it’s back to the surgery table for wider excision, with the size of the hole governed by our experience with that type of cancer. If it’s a really aggressive type of cancer with a high potential for spreading, we may be going back for a bigger crater, even if we had clean borders.
Two surgeries where one would do sounds like a lot of wear and tear on the patient (not to mention your pocketbook). It’s one of those "durned if you do and durned if you don’t" situations. If it’s malignant cancer, you need to go for the gusto. If it turns out to be benign, you’ll be so glad you didn’t amputate the leg to get the benign tumor off the toes.
Speaking of amputating legs to remove the tumor on the toes, in a previous post on cancer, we mentioned that very situation. That little poodle with mast cell tumor turned up clean on all her staging tests, so we went ahead with amputating her front leg. Her pathology report came back today, showing no spread of tumor up the leg. She is recuperating well from her surgery and we have high hopes of extending her life. Only time will tell, but we’ve given her our best shot.