Pathologic Staging Inconsistency Between ypT4N0 (stage II) and ypT1-2N1 (stage III) After Preoperative Chemoradiotherapy and Total Mesorectal Excision in Rectal Cancer: A Multi-Institutional Study.

ABSTRACT

BACKGROUND: In the Surveillance, Epidemiology, and End Results population-based data, the survival curves reversed between T4N0 (stages IIB or IIC) and T1-2N1 (stage IIIA) in rectal cancer. However, T4N0 had a higher stage than T1-2N1 in the current colorectal staging system. PATIENTS AND METHODS: We analyzed 1804 patients with rectal cancer who were treated with preoperative chemoradiotherapy and curative surgery. We grouped patients by pathologic stage, and recurrence-free survival (RFS) and overall survival rates were calculated and compared for each stage. We evaluated prognostic factors that influenced recurrence and survival. RESULTS: In the recurrence and survival analysis, 3-year RFS rates were 95.9% for ypStage 0, 94.0% for ypStage I, 78.9% for ypStage IIA, 55.8% for ypStage IIB/C, 80.2% for ypStage IIIA, 64.6% for ypStage IIIB, and 44.9% for ypStage IIIC. Patients with ypStage IIB/C showed significantly worse RFS (P = .004) than did those with ypStage IIIA. The ypStage IIB/C group showed significantly higher rates of both locoregional recurrence (24.3% vs. 5.5%; P = .02) and distant metastasis (31.6% vs. 17.1%; P = .048) than did the ypStage IIIA group. Compared with ypStage IIIA, ypStage IIB/C showed significantly higher pre-chemoradiotherapy carcinoembryonic antigen (P = .004), circumferential radial margin involvement (P = .001), and positive perineural invasion (P = .014). CONCLUSION: Patients with rectal cancer staged ypT4N0 were associated with higher locoregional recurrence and distant metastasis rates than those staged ypT1-2N1 in the current staging system.