PREOPERATIVE INFUSIONAL CHEMORADIATION AND SURGERY WITH OR WITHOUT ANELECTRON-BEAM INTRAOPERATIVE BOOST FOR ADVANCED PRIMARY RECTAL-CANCER

Purpose: To compare the multimodality treatment results of surgical re section plus preoperative radiotherapy with concomitant protracted inf usion chemotherapy (preop-chemoXRT), with or without an electron beam intraoperative radiotherapy (EB-IORT) boost, in 37 patients having adv anced primary rectal cancer, with the results of a protocol using only preoperative radiotherapy (preop-XRT) plus surgical resection in a hi storic control group of 36 patients. Methods and Materials: Thirty-eig ht patients with tethered T3 or T4 primary rectal cancer were treated with 45 Gy delivered in 25 fractions over 5 weeks plus infusional chem otherapy. Thirty-seven patients underwent surgical resection: 13 (35%) had restorative operations, and the remainder had either abdominoperi neal resection (APR) or pelvic exenteration (PE). Electron beam intrao perative radiotherapy (EB-IORT) was used in doses of 10-20 Gy for 11 p atients with adherent pelvic tumor. In the 36 historic control patient s, the preop-XRT dose was 45 Gy, and 93% of them had APR or PE. Result s: The local recurrence rate was 3% for the preop-chemoXRT group and 3 3% for the historic control group. The 3-year survival rate for patien ts treated with preop-chemoXRT plus resection was 82% compared with 62 % for the historic control group. Distant metastases occurred more fre quently in patients treated with an EB-IORT boost than in patients who were not (64% vs. 19%, p < 0.05), and the overall 3-year survival rat e was lower for the former (67% vs. 96%, p < 0.05). Acute and late tox icities were acceptable. Conclusions: Preop-chemoXRT for advanced prim ary rectal cancer results in better control of pelvic disease and bett er overall survival rates than does preop-XRT alone. With preop-chemoX RT, acute chemoradiation toxicity is increased whereas late morbidity is unchanged compared with preop-XRT alone, Local control in patients with areas of residual or clinically adherent disease is improved by t he use of EB-IORT; however, patients treated with EB-IORT had poorer s urvival rates than those treated without EB-IORT.