When treating a high grade neuroendocrine tumor of the rectum with involved pelvic lymph nodes, do you use the same approach (dose, fractionation, concurrent chemotherapies) as you would for a small cell lung cancer?

I have simply used standard radiation dose and technique with platinum/etopiside or CPT/cis. Twice a day fractionation could be very difficult to tolerate. The proctitis and small bowel toxicity would probably be too severe.