There is ongoing debate regarding the significance of complete or near-complete response after neoadjuvant chemoradiotherapy (CRT) for rectal cancer. This study assessed the prognostic value of the Dworak tumor regression grade (TRG) following neoadjuvant CRT and surgery in patients with pathological stage (ypStage) II and III rectal cancer.
The records of 331 patients who underwent neoadjuvant CRT followed by total mesorectal excision between 2004 and 2015 were retrospectively reviewed. Patients were categorized as having a good response (GR = TRG 3 + 4, n = 122) or a poor response (PR = TRG 1 + 2, n = 209).
At a median follow-up of 65 months, 5-year disease-free survival (DFS) was higher in the GR group than in the PR group (91.3% vs. 66.6%, p < 0.001). DFS was 90.7% in ypStages 0–I, 75.9% in ypStage II, and 56.6% in ypStage III (p < 0.001). Patients with a GR and ypStage II disease had a DFS that was indistinguishable from that of patients with ypStage 0–I disease (p = 0.885) and somewhat, although not significantly, better than that of patients with a PR and ypStage II disease (92.3% vs. 72.8%, p = 0.110). Likewise, patients with a GR and ypStage III disease had a 5-year DFS similar to those with ypStage II disease (p = 0.789) and significantly better than that of patients with a PR and ypStage III disease (76.0% vs. 51.3%, p = 0.040). The same pattern was observed for overall survival (OS). Multivariate analysis revealed that TRG 3 + 4 (hazard ratio: 0.35, 95% confidence interval: 0.19–0.66), ypN classification, and perineural invasion were independently associated with DFS.
A GR to neoadjuvant CRT is an independent predictor of good DFS and OS and further stratifies patients so as to estimate the risk of recurrence and survival among patients with ypStage II and III rectal cancer.
Clinical trial identification
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Jae-Sung Kim MD.
Has not received any funding.
All authors have declared no conflicts of interest.