[Analysis of efficacy and prognostic factors of neoadjuvant chemoradiotherapy in locally advanced mid-low rectal cancer patients with RAS gene mutation].

Authors

Y B Li, Y C Yang, X L Geng, X F Yang, W Gong, L J Zhao

Published in

Zhonghua yi xue za zhi. Volume 106. Issue 37. Pages 4018-4025. Oct 13, 2026.

Abstract

Objective: To analyze the efficacy of neoadjuvant chemoradiotherapy and the factors influencing survival in patients with locally advanced mid-low rectal cancer harboring rat sarcoma virus (RAS) gene mutation. Methods: A retrospective analysis of clinical data from patients with locally advanced mid-low rectal cancer who received neoadjuvant long-course chemoradiotherapy at the Affiliated Hospital of Zunyi Medical University between June 2018 and June 2020 was conducted. Patients were divided into a mutation group (patients with RAS gene mutation) and a wild-type group (patients without RAS gene mutation) based on RAS gene mutation status. Follow-up was carried out until December 31, 2025. The efficacy of neoadjuvant chemoradiotherapy in patients with locally advanced mid-low rectal cancer harboring RAS gene mutation was analyzed, including general information, perioperative indicators, clinical pathological characteristics, pathological remission, overall complete remission, neoadjuvant rectal (NAR) score, recurrence-free survival (RFS) rate, and overall survival (OS) rate. A multivariate logistic regression model was used to analyze the influencing factors of overall complete remission and NAR score. A multivariate Cox regression model was used to analyze the influencing factors of patient survival. Results: A total of 146 patients were enrolled, including 62 in the mutation group [39 males and 23 females, aged (61±8) years] and 84 in the wild-type group [62 males and 22 females, aged (62±8) years]. The RAS mutation rate was 42.5% (62/146), with KRAS mutations accounting for 98.4% (61/62). There was no statistically significant difference in baseline demographic characteristics of general information and perioperative indicators between the wild-type group and the mutation group (all P>0.05). The proportion of patients with ypT3 staging [61.0% (36/59) vs 29.9% (23/77), P=0.014] and NAR scores [M (Q₁, Q₃), 15 (8, 30) vs 8 (8, 15) points, P=0.042] were higher in the mutation group than those in the wild-type group. Multivariate logistic regression analysis showed that RAS mutation was an influencing factor with high NAR scores (OR=2.33, 95%CI: 1.00-5.41, P=0.049), but it is not a factor influencing overall complete remission (OR=0.71, 95%CI: 0.28-1.77, P=0.463). The follow-up duration was 65 (49, 83) months. The 5-year RFS rate was lower in the mutation group than that in the wild-type group (65.5% vs 82.6%, P=0.010), while there was no statistically significant difference in 5-year OS rate between the two groups (93.0% vs 98.4%, P=0.344). Cox regression analysis indicated that RAS mutation was a risk factor for 5-year RFS rate (HR=2.47, 95%CI: 1.21-5.05, P=0.013). Conclusions: Patients with locally advanced mid-low rectal cancer harboring RAS gene mutation had a higher proportion of ypT3 staging and higher NAR scores, as well as lower 5-year RFS rate. RAS gene mutation is a risk factor for high NAR scores and low 5-year RFS rate in patients with locally advanced mid-low rectal cancer after neoadjuvant chemoradiotherapy.

PMID:
42855771
Bibliographic data and abstract were imported from PubMed on 10 Oct 2026.

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