Background: Colorectal cancer (CRC) is the most common cancer and the leading cause of cancer-related death globally. While survival improved, CRC patients face the risk of subsequent multiple primary cancers (MPCs). This study aimed to determine the incidence and identify risk factors associated with metachronous MPCs among CRC survivors.Methods: A retrospective analysis was performed on adults diagnosed with invasive colorectal adenocarcinoma at Flinders Medical Centre from 2011 to 2024, who had at least 6 months of post-CRC follow-up. Sociodemographic factors, clinical information, tumour characteristics, and treatment types were collected. Cumulative incidence function and sub-distribution hazard models were used to estimate the incidence and identify risk factors of developing MPCs.Results: Of the total 554 eligible study participants, 12% developed MPC, with a median follow-up time of 5 years (interquartile range: 2.8–7.6 years) until the diagnosis of MPC. Gastrointestinal, prostate, and haematological malignancies were the most common types of MPCs identified. The cumulative incidence and standardised incidence ratio (SIR) of an MPC were 20.9% (95% CI: 15.3–25.6) and 1.32 (95% CI: 1.03–1.68), respectively. Male sex, older age (>65 y), early-stage cancer, and loss of mismatch repair (MMR) protein expression were associated with an increased risk of developing MPCs.Conclusions: CRC survivors have a higher risk of developing an MPC compared to the general population. Sex, age, cancer stage, and MMR protein expression are factors associated with MPCs. Therefore, tailored surveillance based on the individual’s risk profile should be considered for timely diagnosis of subsequent cancers to improve long-term outcomes.
背景：结直肠癌是全球最常见的癌症，也是癌症相关死亡的主要原因。尽管生存率有所提高，但结直肠癌患者仍面临发生后续多原发癌的风险。本研究旨在确定结直肠癌幸存者中异时性多原发癌的发病率，并识别其相关风险因素。 方法：对2011年至2024年间在弗林德斯医疗中心诊断为侵袭性结直肠腺癌、且结直肠癌后随访至少6个月的成年患者进行回顾性分析。收集了社会人口学因素、临床信息、肿瘤特征及治疗类型。采用累积发生率函数和竞争风险模型来估计多原发癌的发病率并识别其风险因素。 结果：在554名符合条件的研究参与者中，12%的患者发生了多原发癌，从结直肠癌诊断到多原发癌诊断的中位随访时间为5年（四分位距：2.8–7.6年）。胃肠道、前列腺和血液系统恶性肿瘤是最常见的多原发癌类型。多原发癌的累积发生率和标准化发病率分别为20.9%（95% CI: 15.3–25.6）和1.32（95% CI: 1.03–1.68）。男性、年龄较大（>65岁）、早期癌症以及错配修复蛋白表达缺失与发生多原发癌的风险增加相关。 结论：与普通人群相比，结直肠癌幸存者发生多原发癌的风险更高。性别、年龄、癌症分期和错配修复蛋白表达是与多原发癌相关的因素。因此，应考虑基于个体风险特征制定个体化监测方案，以便及时诊断后续癌症，从而改善长期预后。
Risk Factors of Multiple Primary Cancers Among Colorectal Cancer Survivors
肿瘤(癌症)患者之家