Efficacy comparison of different modes of neoadjuvant therapy for locally advanced rectal cancer with proficient in mismatch repair intact or microsatellite stability
10.3760/cma.j.cn115355-20240407-00161
- VernacularTitle:错配修复完整或微卫星稳定型局部晚期直肠癌不同模式新辅助治疗效果比较
- Author:
Di SONG
1
;
Yonggang SHI
1
;
Xiaodan HAN
1
Author Information
1. 郑州大学第一附属医院放疗科，郑州 450052
- Publication Type:Journal Article
- Keywords:
Rectal neoplasms;
Total neoadjuvant therapy;
Short-course radiotherapy;
Immune checkpoint inhibitors
- From:
Cancer Research and Clinic
2025;37(1):8-13
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the therapeutic efficacy of different modes of neoadjuvant therapy for locally advanced rectal cancer (LARC) with proficient in mismatch repair intact (pMMR) or microsatellite stability (MSS).Methods:A retrospective case series study was conducted. A total of 210 LARC patients with pMMR or MSS admitted to the First Affiliated Hospital of Zhengzhou University from January 2020 to December 2022 were selected. Patients were divided into the chemotherapy alone group (98 cases) and the total neoadjuvant therapy (TNT) group (112 cases) based on different neoadjuvant treatment modes. The pathological complete remission (pCR) rate of both groups was compared. In the TNT group, 24 patients received short-course radiotherapy (SCRT) plus chemotherapy (group A), 62 patients received SCRT plus chemotherapy combined with immunotherapy (group B), 23 patients received long-course radiotherapy (LCRT) plus chemotherapy (group C), and 3 patients received LCRT plus chemotherapy combined with immunotherapy (group D). The pCR rate, tumor down-staging and the incidence of adverse reactions were compared between the 4 groups. A subgroup analysis was performed in 87 patients with the distance from the tumor site to anal verge >5 cm and T 2-3N 0-2M 0 TNM staging. And then 87 patients were divided into the chemotherapy alone group (47 cases) and the TNT group (40 cases), and the overall survival (OS) and disease-free survival (DFS) of patients were compared between the 2 groups. Results:Among the 210 LARC patients, 126 cases were male and 84 cases were female, with the age of (51±11) years. There were 3 cases in clinical stage Ⅱ and 207 cases in clinical stage Ⅲ; 68 cases with the distance from the tumor site to the anal verge <5 cm and 142 cases with the distance from the tumor site to the anal verge ≥ 5 cm. The pCR rate of the TNT group was higher than that of the chemotherapy alone group [40.2% (45/112) vs. 7.2% (7/98)], and the difference was statistically significant ( χ2 = 30.62, P < 0.001). In group D, 1 patient achieved pCR, but no statistical comparison was made due to the small sample size. There was no statistically significant difference in pCR rate between group A and group C [25.0% (6/24) vs. 21.7% (5/23), χ2 = 0.07, P = 0.792]. The pCR rate of group B was higher than that of group A and group C [53.2% (33/62) vs. 25.0% (6/24), 53.2% (33/62) vs. 21.7% (5/23)], and the differences were statistically significant ( χ2 = 5.56, P = 0.029; χ2 = 6.73, P = 0.013). However, there were no statistically significant differences in T and N down-staging among group A, group B and group C (all P > 0.05). During neoadjuvant treatment, the incidence of grade 3-4 myelosuppression was 10.7% (12/112) in the TNT group, and no grade 3-4 radiation proctitis was observed. The incidence of granulocytopenia in group B was lower than that in group A, and the incidence of thrombocytopenia in group was lower than that in group C; and the differences were statistically significant (all P < 0.05). In the subgroup analysis, there were no statistically significant differences in OS and DFS between the chemotherapy alone group and the TNT group ( χ2 = 2.17, P = 0.141; χ2 = 0.24, P = 0.624). Conclusions:The neoadjuvant treatment of SCRT combined with immunotherapy has a high pCR rate and a good safety in LARC patients with pMMR or MSS. TNT is not effective in improving the survival of low-risk LARC patients with tumors located in the mid to high segment of the rectum and may have the risk of overtreatment.
