For a patient who has undergone preoperative chemoradiation to 50Gy for locally advanced rectal cancer followed by LAR or APR, would you treat a positive margin with radiation therapy?
If so, what dose?
Answer from: Radiation Oncologist at Academic Institution
No. The majority are still controlled locally even with a positive margin. The cells seen on histologic evaluation may be clonogenicly dead. After an 8-12 week interval, there is not much that can be done with more irridation anyway. Previuosly irradiated fixed bowel could be in the field. Furthermo...
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Answer from: Radiation Oncologist at Community Practice
This is somewhat controversial, IORT if available should be considered for very close or positive margins. If IORT is not available 10-20Gy external beam radiation to a limited volume soon after surgery. Image guidance is an issue though and discussion with surgeon should be done to delineate t...