Prognostic groups in 1,676 patients with T3 rectal cancer treated without preoperative radiotherapy

The use of preoperative radiotherapy in patients with T3 tumors shows considerable variation among countries and institutions. The Norwegian guidelines have been very restrictive, limiting the indication to T4. This study was designed to identify subgroups of patients with T3 tumors with presumed high risks on adverse outcome and to use these results to reevaluate the national guidelines for preoperative radiotherapy.

This was a national cohort study of 2,460 patients with pT3 rectal adenocarcinoma, undergoing major surgery without preoperative radiotherapy from November 1993 to December 2002. Circumferential resection margin in millimeters was given for 1,676 patients.

Multivariate analyses identified circumferential resection margin and nodal status as independent prognostic factors for local recurrence, metastases, and overall mortality. Analyses based on 12 combinations of N stage and circumferential resection margin showed that the estimated five-year rate of local recurrence increased from 11.1 percent (circumferential resection margin >3 mm; N0) to 36.5 percent (circumferential resection margin < or =1 mm; N2). The rate of distant metastases increased from 18.5 to 77.7 percent and the five-year survival decreased from 68.6 to 25.7 percent, respectively.

There is great variation in outcome for patients with T3 cancers, and the outcome is not acceptable for the groups of patients with circumferential resection margin <3 mm or involved lymph nodes. These groups should be considered for neoadjuvant therapy.