Preoperative radio-chemotherapy (RT-CT) in rectal cancer. Prospective study with postoperative RT-CT control group.

INTRODUCTION: Between 1996 and 2000, the colorectal tumour committee of the Hospital Universitario de Bellvitge and the Institut Català d'Oncologia, Hospitalet, carried out a non-randomised prospective study of pre-op radio-chemotherapy (RT-CT) in locally advanced rectal tumours. We herein present the results. On the other hand, and at the same time, patients operated on for locally advanced rectal cancer were admitted and treated by RT-CT during the postoperative process, according to our standard protocol. Results for both series are compared.

MATERIAL AND METHODS: The preoperative RT-CT group included 94 patients. They received radiotherapy (RT), 45 Gy on posterior pelvis, and simultaneously, 5-fluorouracil (5FU) by continuous infusion (300 mg/m2/day, 5 days weekly during RT). Surgical intervention was scheduled 6-8 weeks after preoperative treatment; after surgery they received 5FU (425 mg/m2/day) and leucovorin (20 mg/m2/day) bolus, 5 days weekly; 4 cycles at four-week intervals. 237 patients who had been previously operated on and who had been staged as T3-T4 and/or N+, M0 were admitted to our centre during the same time period and received postoperative RT-CT.

RESULTS: The preoperative treatment group showed a complete and global response rate to RT-CT in 17% and 68% of cases, respectively. Anal sphincter was preserved in 38.5% of patients exhibiting low rectal tumours (inferior limit of tumour at 6 cm or less from the anal margin). Overall and disease-free survival at 5 years was distinct, showing statistical significance, according to the response obtained through preop treatment; it was better in responsive patients (overall survival: 87% in complete remissions, 75% in partial remissions, 48% in stable disease, and mean survival was 0.84 years for patients who evolved, p<0.05; disease-free survival was: 93% in complete remission, 76% partial remission, 39% in stable disease, p=0.001). We did not see any difference with regard to overall survival, disease-free survival or local control at the time of comparing either pre- or postoperative groups. There were, however, differences with regard to late toxicity; they showed less toxicity when RT-CT was administered preoperatively; no case of radiation enteritis that required surgery was seen in this group, whereas in the postoperative RT-CT it was 4.2%, p=0.022.

CONCLUSIONS: Preoperative treatment of locally advanced rectal cancer is recommended, for it yields a high level of response to treatment; it allows preservation surgery of the anal sphincter in one third of patients showing low rectal tumours. There is also a clear diminution of late toxicity with pre-op treatment. On the other hand, response to pre-op treatment selects patients with a better prognosis.