Preoperative hyper-fractionated accelerated radiotherapy (HART) in locally advanced rectal cancer (LARC) immediately followed by surgery. A prospective phase II trial.

Abstract

We aim to report on local control in a phase II trial on preoperative hyper-fractionated and accelerated radiotherapy schedule (HART) in locally advanced resectable rectal cancer (LARC). This fractionation schedule was designed to keep the overall treatment time (OTT) as short as possible. This is a prospective trial on patients with UICC stages II and III rectal cancer. The patients were submitted to a total dose of 41.6 Gy, delivered in 2.5 weeks at 1.6 Gy per fraction twice a day with a 6-h interfraction interval. Surgery was performed within 1 week after the end of irradiation. Adjuvant chemotherapy was delivered in a subset of patients. Two hundred and seventy nine patients were entered and 250 are fully assessable, with a median follow-up of 39 months. The 5-years actuarial local control (LC) rate is 91.7%. The overall survival (OS) is 59.6%. The freedom from disease relapse (FDR) is 71.5%. Downstaging was observed in 38% of the tumors. The actuarial LC at 5 years is 91.7%, although we are dealing with stages II-III LARC, mainly located in the lower rectum (median distance = 5 cm). The pattern of failure is dominated by distant metastases and treatment intensification will obviously require a systemic approach.