Perineural invasion as an independent predictor of early recurrence within 1 year after total mesorectal excision for rectal cancer.

[BACKGROUND] Although advances in rectal cancer treatment have led to improved survival outcomes, a proportion of patients still experience recurrence within a short period after receiving curative treatment. Early recurrence is a significant burden on both patients and clinicians. This study aimed to evaluate the clinicopathological characteristics associated with early recurrence of rectal cancer in patients who underwent total mesorectal excision.

[METHODS] This retrospective cohort study included patients who underwent total mesorectal excision for rectal cancer between 2004 and 2018. Patients presenting with metastatic disease, colon cancer, or anal cancer, those requiring emergency surgery, or individuals diagnosed with hereditary malignancies were excluded from the analysis. From this cohort, patients who developed recurrence during the follow-up period after curative surgery were selected. Patients were classified into the early recurrence group (ER group; recurrence within 12 months after surgery) and the late recurrence group (LR group; recurrence more than 12 months after surgery). The baseline characteristics, perioperative factors, and histopathological findings were compared between the groups. Univariate and multivariate logistic regression analyses were employed to identify independent predictive factors for early recurrence.

[RESULTS] A total of 132 patients with recurrence were analyzed (ER group: 42, LR group: 90). The median follow-up duration was 44.1 months. No statistical differences were observed between the two groups in the baseline characteristics, perioperative outcomes, and histopathological findings, except for perineural invasion (ER vs. LR, 52.4% vs. 16.7%,  < 0.001). Additionally, recurrence patterns were descriptively similar between the two groups. In multivariate logistic regression analysis, perineural invasion was associated with early recurrence (odds ratio 4.930, 95% confidence interval 2.077–11.699;  < 0.001). The ER group exhibited worse overall survival than that noted with the LR group (5-year overall survival, 19.0% vs. 53.9%,  = 0.001).

[CONCLUSION] Perineural invasion was identified as an independent predictive factor for early recurrence within 12 months after curative surgery for rectal cancer and was associated with poorer survival outcomes.