Some institutions are adding doxorubicin or carboplatin chemotherapy to radiotherapy protocols. This seems to be well tolerated and needs further investigation. Those cats who were treated after their first surgery were more likely to fall in to this category. For those cats that did develop recurrence, the median disease free interval was approximately 18 months. In cases in which attempted resection may result in a very large incision, and especially if this incision may extend over the thorax, pre operative radiation should be considered.
Radiation has the potential to kill the tumor cells that are on the edge of the tumor.
These are the cells that most often are missed at surgery as they are not grossly detectable. The visible tumor will not likely shrink, so the owners should be warned that they may see no change during radiation therapy. Surgery is then planned for 2-3 weeks after radiation. This technique may be preferred to post operative radiation in cats with large tumors, but is not likely to make an unresectable tumor resectable. What it does is decrease the probability that microscopic residual disease will still be present if 3 cm margins are not attainable.