Most cases of rectal cancer (RC) in our institution are in pathologic stage T3. They are a heterogeneous group but have been classified in a single-stage category. We performed the present study to validate the prognostic significance of the mesorectal extension depth (MED) in T3 RC measured in millimeters beyond the muscularis propria plane.Materials and Methods
We performed a retrospective analysis of 104 patients with T3 RC who had undergone curative surgery after a course of preoperative chemoradiotherapy at a tertiary referral cancer hospital. The patients were grouped by MED (T3a, < 1 mm; T3b, 1-5 mm; T3c > 5-10 mm; and T3d > 10 mm). The clinicopathologic data and disease-free survival were analyzed.Results
The 5-year disease-free survival rate according to the T3 subclassification was 87.5% for those with T3a, 57.9% for T3b, 38.7% for T3c, and 40.3% for those with T3d tumors (P = .050). On univariate and multivariate analysis, the prognostic factors affecting survival were overall recurrence (hazard ratio [HR], 3.670; 95% confidence interval [CI], 1.710-7.837; P = .001), histologic grade (HR, 2.204; 95% CI, 1.156-4.199; P = .016), mesorectal invasion depth (HR, 1.885; 95% CI, 1.164-3.052; P = .010), and lymph node metastasis (HR, 1.211; 95% CI, 1.015-1.444; P = .033).Conclusion
MED is a significant prognostic factor in patients with T3 RC who have undergone neoadjuvant chemoradiotherapy, especially when the MED is > 5 mm. The MED could be as important as other clinicopathologic factors in predicting disease-specific survival.Micro-Abstract
The present study evaluated the prognostic significance of mesorectal extension depth (MED) in stage T3 rectal cancer. An analysis of 104 patients with curative surgery after preoperative chemoradiotherapy were grouped by the MED (T3a, < 1 mm; T3b, 1-5 mm; T3c > 5-10 mm; and T3d > 10 mm). The 5-year survival rate was 87.5% for those with stage T3a, 57.9% for T3b, 38.7% for T3c, and 40.3% for those with stage T3d (P = .050). On univariate and multivariate analysis, MED was a significant prognostic factor.