Histopathological predictors for local recurrence in patients with T3 and T4 rectal cancers without preoperative chemoradiotherapy

BACKGROUND AND OBJECTIVES: Identification of suitable predictors of local recurrence (LR) in patients with rectal cancer would be of clinical benefit. The aim of this study was to identify histopathological factors that could predict LR. METHODS: A total of 796 stage II/III patients with pT3 and pT4 rectal cancer who did not undergo preoperative chemoradiation were enrolled. LR was defined as intra-pelvic recurrence only. Histopathological factors related to LR were investigated. RESULTS: LR was found in 25 patients (6.1%) with stage II and 54 patients (13.9%) with stage IIIB/IIIC. In patients with stage II, distance of mesorectal extension (DME) >4 mm (P = 0.011) and positive venous invasion (P = 0.035) were independent factors that predicted LR. In patients with stage IIIB/IIIC, circumferential resection margin (CRM) ≤1 mm (P = 0.003) and positive lymphatic invasion (P = 0.006) were independent factors. The cumulative 5-year LR rate was higher (11.9%) in patients with a combination of DME > 4 mm and/or positive venous invasion for stage II (P < 0.001), and was also higher in patients with a combination of CRM≤1 mm and/or positive lymphatic invasion for stage IIIB and IIIC (22.2%; P < 0.002, and 34.3%; P < 0.006, respectively). CONCLUSIONS: Important histopathological predictors for LR in patients with pT3 and pT4 rectal cancer were different at each stage.