Postoperative irradiation combined with chemotherapy for high-risk rectal cancer patients: The timing of radiotherapy

In a prospective open-study we evaluated the combination of radiation therapy and adjuvant 5-FU plus levamisole in controlling Modified Astler- Coller (MAC) B2 or C rectal cancer following a curative-intended surgery. Sixty-four consecutive rectal cancer patients were treated by adjuvant radiation therapy (Linac 8 MV, 50-50.4 Gy to an isocentric pelvis brick volume in 5 fractions per week each of 1.8-2 Gy), and 12 monthly courses of 5-fluorouracil (375 mg/m²/day for 5 consecutive days) plus levamisole (50 mg t.i.d. for 3 days). Within a median follow-up period of 36 months, 19 patients (29.6%) experienced relapses. The 3-year-DFS of MAC B2 patients was 82%, compared with 60% in MAC C. Early radiation treatment was not associated with a higher proportion of relapses, while late radiation therapy initiation was associated with a significantly higher proportion of relapses. Early radiation therapy, not later than following the 2nd to 4th course of chemotherapy, is associated with the more acceptable proportion of relapses.