Preoperative Radiotherapy as Adjuvant Treatment in Rectal Cancer

TLDR

A randomized EORTC trial enrolled 466 rectal cancer patients (T2–T4) and administered 34.5 Gy of pre‑operative radiotherapy in 15 fractions before radical surgery. The trial showed acceptable toxicity, no statistically significant overall survival advantage, but a significant reduction in 5‑year local recurrence (30 % vs 15 %) and a trend toward higher survival in the curative‑surgery subgroup (59.1 % vs 69.1 %), supporting pre‑operative radiotherapy for locally advanced disease.

Abstract

A randomized clinical trial was conducted by the European Organization for Research and Treatment for Cancer (EORTC) Gastrointestinal Cancer Cooperative Group to study the effectiveness of irradiation therapy administered in a dosage of 34.5 Gy, divided into 15 daily doses of 2.3 Gy each before radical surgery for rectal cancer (T2, T3, T4, NX, MO). Four hundred sixty-six patients were entered in the clinical trial between June 1976 and September 1981. Tolerance and side effects of pre- operative irradiation were acceptable. The overall 5-year survival rates were similar in both groups. When considering only the 341 patients treated by surgery with a curative aim, the 5-year survival rates were 59.1% and 69.1% in the control group and in the combined modality group, respectively (p = 0.08). The local recurrence rates at 5 years were 30% and 15% in the control group and the adjuvant radiotherapy group, respectively (p = 0.003). Although this study did not show preoperative radiotherapy to have a statistically significant benefit on overall survival, it does have a clear effect on local control of rectal cancer. Therefore, before performing radical surgery, this adjuvant therapy should be administered to patients who have locally extended rectal cancer.