Local control with pre-operative radiotherapy alone versus "sandwich" radiotherapy for rectal carcinoma.

Forty-nine patients with primary adenocarcinoma of the rectum, clinically localized to the pelvis were treated with pre-op radiotherapy (RT) 1500 cGy/5 fx with AP/PA fields, followed by immediate curative resection. Patients staged as Astler-Coller B2, C1, or C2 were considered for post-op RT, 4140 cGy/23 fxs with a 4-field technique. There were 47 evaluable patients in this non-randomized study. Two groups of patients were analyzed, namely pre-op RT only (24 patients) and combined pre- and post-op ("sandwich") RT (23 patients). Two patients with pre-op RT only were considered inevaluable for recurrence because they died NED at 1 and 7 mo. All patients have been followed for greater than 1 year; 77% have been followed for greater than 2 yr. There has been only one local recurrence (LR), surprisingly in a Stage A pre-op RT patient who had no residual tumor in the final operative specimen. In the pre-op group which included 10 B2s, and 1 C2, 1500 cGy in 5 days (equivalent to 1940 cGy by the NSD formulation) was associated with no local recurrence. No distant metastases (DM) have developed in this group. In the "sandwich" RT group, which included 3 B2s, 1 C1, 17 C2s, and 1 D (localized to the pelvis, i.e. ovary), there were no LRs and 7 DMs (1 B2 and 6 C2s). Actuarial survival is 92% in the pre-op RT group at 2 and 3 yr, and 82% in the "sandwich" group at 2 and 3 yr. There have been no serious early or late complications related to RT in our pre-op group. The use of 1500 cGy in 5 days as pre-op RT with immediate surgery may prove, upon longer follow-up, to be sufficient for increasing local control, with minimum morbidity, in patients with B2 disease. Patients with C2 disease are being controlled locally with the "sandwich" regimen, but it is not clear whether pre-op RT alone may be adequate in this group as well. We are now addressing this question in a randomized study.