A Modified Classification of Prognostic Factors Based on Pathological Stage and Tumor Regression Grade in Patients with Rectal Cancer Who Receive Preoperative Chemoradiotherapy.

OBJECTIVE

The histologic response to neoadjuvant chemoradiotherapy (CRT) has been intimately related to outcomes in locally advanced rectal cancer. However, reliable prognostic factors have yet to be established.

SUBJECTS AND METHODS

The study group comprised 198 patients with locally advanced rectal cancer who received CRT. A modified classification based on the combination of ypStage and tumor regression grade (TRG) was developed. ypStage II with TRG 2 was classified as ypTRGstage IIA, and ypStage II with TRG 3 or 4 was classified as ypTRGstage IIB. ypStage 0 and ypStage I were classified as ypTRGstage I, and ypStage III was classified as ypTRGstage III.

RESULTS

The 5-year disease-free survival (DFS) was 83% in ypTRGstage I, 86% in ypTRGstage IIA, 57% in ypTRGstage IIB, and 60% in ypTRGstage III (p = 0.0001). The 5-year DFS in ypTRGstage IIA did not differ significantly from that in ypStage 0 (p = 0.865) or ypStage I (p = 0.585). The 5-year DFS in ypStage IIB did not differ from that in ypStage III (p = 0.912). Multivariate analysis showed that ypTRGstage was an independent risk factor for DFS.

CONCLUSION

A modified classification allows patients with ypStage II locally advanced rectal cancer to be clearly divided into two groups: responders and nonresponders.