Adjuvant preoperative radiotherapy for locally advanced rectal carcinoma. Results of a prospective, randomized trial

A prospective, randomized clinical trial was conducted by the Northwest Rectal Cancer Group to study the effects of preoperative radiotherapy given one week before surgery in locally advanced (tethered or fixed) rectal carcinoma.

A total of 284 patients were entered into the trial between 1982 and 1986; 141 were allocated to receive surgical treatment alone, and 143 were allocated to receive preoperative radiotherapy. A 10 x 10 x 10 cm volume in the posterior pelvis, centered on the tumor, was irradiated at a dose of 20 Gy, divided into four daily fractions of 5 Gy each.

No differences were observed in any of the clinicopathologic variables in the two arms of the trial; there were no striking down-staging effects in the irradiated tumors. After a minimum follow-up period of 96 months, the overall and cancer-related mortality rates were similar in both arms of the study (P = 0.21 and P = 0.09, respectively). There was a highly significant reduction in local recurrences in the irradiated group (12.8 percent x-ray therapy vs. 36.5 percent surgery; P = 0.0001). The majority of local recurrences after preoperative radiotherapy occurred inside the radiotherapy field (10 cases; 7 percent), with only six cases (5 percent) outside the field. No significant difference was observed in the rates of distant metastasis between the two treatment groups (P = 0.73).

Although there is no statistically significant survival benefit in the whole series, there is a survival benefit for the subset of patients considered by the surgeon to have undergone a curative operation. We recommend that this form of adjuvant therapy should be offered to all patients with locally advanced rectal cancer who are to undergo radical surgery.