To evaluate the long-term effects on survival and recurrence rates of preoperative radiotherapy in the treatment of curatively operated rectal cancer patients.

Of 1,168 randomly assigned patients in the Swedish Rectal Cancer Trial between 1987 and 1990, 908 had curative surgery; 454 of these patients had surgery alone, and 454 were administered preoperative radiotherapy (25 Gy in 5 days) followed by surgery within 1 week. Follow-up was performed by matching against three Swedish nationwide registries (the Swedish Cancer Register, the Hospital Discharge Register, and the Cause of Death Register).

Median follow-up time was 13 years (range, 3 to 15 years). The overall survival rate in the irradiated group was 38% v 30% in the nonirradiated group (P = .008). The cancer-specific survival rate in the irradiated group was 72% v 62% in the nonirradiated group (P = .03), and the local recurrence rate was 9% v 26% (P < .001), respectively. The reduction of local recurrence rates was observed at all tumor heights, although it was not statistically significant for tumors greater than 10 cm from the anal verge.

Preoperative radiotherapy with 25 Gy in 1 week before curative surgery for rectal cancer is beneficial for overall and cancer-specific survival and local recurrence rates after long-term follow-up.