Pathologic Features of Rectal Adenocarcinoma after Preoperative Neoadjuvant Chemoradiation Therapy and the Prognostic Factors for Local Recurrence: A Retrospective Study at Maharaj Nakorn Chiang Mai Hospital.

Abstract

Background: Colorectal cancer is a significant global health concern, with Thailand reporting notable incidence rates. Locally advanced rectal cancer demands effective treatment strategies to reduce the risk of local recurrence post-surgery; however, the predictive factors for local recurrence are uncertain..

Objective: This study investigated patients with rectal adenocarcinoma undergoing preoperative concurrent chemoradiation (CCRT). The pathological findings and predictors of local recurrence in rectal adenocarcinoma were examined following preoperative CCRT.

Methods: A retrospective cohort study was conducted in patients with rectal adenocarcinoma who underwent preoperative CCRT and surgery at the Maharaj Nakorn Chiang Mai Hospital from January 2018 to December 2022. Data were collected from patients to investigate the associations between pathological prognostic factors and local recurrence of rectal adenocarcinoma. For the analysis of continuous variables, the Student's t-test was employed to assess univariate associations. In the case of categorical variables, comparisons were made using the chi-square test and the Kruskal-Wallis test. Furthermore, the Kaplan-Meier method, supplemented by the log-rank test, was utilized to examine the relationships between baseline prognostic variables and disease-free survival endpoints.

Results: Of the 70 patients who received preoperative CCRT, 14 (20%) experienced recurrence. Univariate log-rank analysis identified five pathologic predictors of the disease-free survival of preoperative CCRT patients: ypT stage (p = 0.0030), lymphatic space invasion (p = 0.0033), venous invasion (p = 0.0345), circumferential resection margin (CRM) (p = 0.0003), and TNM staging (p = 0.0109). In multivariate Cox regression analysis, ypTNM stage and CRM status were independent predictors for disease progression of preoperative CCRT patients.

Conclusion: ypTNM staging and CRM status emerged as independent predictors of local recurrence. The study also identified age and gender variations in rectal cancer incidence, highlighting the importance of tailored screening approaches.