Association between postoperative radiotherapy for bladder cancer and second primary rectal cancers: a retrospective cohort study
10.3760/cma.j.cn112271-20230723-00016
- VernacularTitle:膀胱癌术后放疗与第二原发直肠恶性肿瘤的关联性研究：一项基于大队列的回顾性研究
- Author:
Weibo SUN
1
;
Mingxia SUN
;
Haiting LI
;
Ziyuan LI
;
Qin TIAN
;
Lijia MA
;
Zechen YAN
;
Yilin REN
;
Zhongyang LIU
;
Xiaojun CHENG
;
Shaocheng ZHU
Author Information
1. 河南省人民医院 郑州大学人民医院 河南大学人民医院肿瘤中心，郑州 450003
- Keywords:
Bladder cancer;
Second primary tumor;
Rectal cancer;
Radiotherapy
- From:
Chinese Journal of Radiological Medicine and Protection
2024;44(5):367-373
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the association between postoperative radiotherapy for bladder cancer and the risk of second primary rectal cancer.Methods:Eligible 75 120 patients with bladder cancer from the Surveillance, Epidemiology, and End Result database (SEER) of the National Cancer Institute (NCI) (1975-2017) were enrolled in this study. The second primary cancers referred to rectal cancers patients suffered after more than five years post-treatment for bladder cancer, and the cumulative incidence was estimated using Fine-Gray competing risk regression. The relative risk (RR) of rectal cancer in patients treated with or without radiotherapy (the RT group or the NRT group) was evaluated using Poisson regression.Results:Among the 75 120 patients, 70 045 (92.4%) were Caucasian, with a median age of 65.8 years (54-74 years). A total of 2 236 (3%) received postoperative radiotherapy, while 72 884 (97%) received surgery alone. The 30-year follow-up revealed a cumulative incidence of rectal cancer of 0.93% in the RT group and 0.43% in the NRT group ( P = 0.004). The competing risk regression analysis identified a significant association between radiotherapy and rectal cancer ( HR: 1.86; 95% CI 1.26-2.74, P < 0.009). Furthermore, the RR of radiotherapy-associated rectal cancer significantly increased as the diagnosis occurred earlier (1975-1985 vs. 1985-1994: RR 2.59; 95% CI 1.20-4.86, P < 0.001), and a lower age at the time of radiotherapy was associated with a higher probability of second primary tumors (≤50-year old vs. > 50 year old : RR 7.89, 95% CI 2.97-21.30, P < 0.001). As calculated using the Poisson distribution, the RR of second rectal tumors was higher in the RT group ( RR: 2.20, 95% CI 1.45-3.18, P < 0.001), even after adjusting the date of diagnosis ( RR: 1.77, 95% CI 1.17-2.57, P = 0.009). Conclusions:An increased risk of rectal cancer following bladder cancer radiotherapy necessitates aggressive follow-ups for the purpose of early detecting second primary rectal cancer associated with bladder cancer radiotherapy.
