Background: Postoperative radiation therapy (RT) after lumpectomy reduces the risk of locoregional recurrence in ductal carcinoma in situ (DCIS). However, the potential association between RT and ischemic heart disease (IHD) remains uncertain. This nationwide cohort study evaluated the long-term impact of postoperative RT on IHD risk and overall survival (OS) in women with DCIS using real-world data from the Korean National Health Insurance Service (NHIS). Methods: Women diagnosed with DCIS who underwent breast-conserving surgery between 2003 and 2020 were identified from the NHIS claims database. Patients with invasive breast cancer, age under 20 years, a prior history of IHD, or missing smoking or body mass index (BMI) data were excluded. Multivariable Cox regression was performed to assess the association between postoperative RT, IHD incidence, and OS, adjusting for key cardiovascular risk factors. Results: Among 4633 eligible patients (RT, 2778; no RT, 1855), the median follow-up duration was 86.1 months, and baseline characteristics were well balanced between groups without major differences in cardiovascular risk factors. A total of 126 patients (3.4%) developed IHD, with a 10-year cumulative incidence of 4.7%. Older age, hypertension, and hyperlipidemia were independent risk factors for IHD, whereas postoperative RT was not significantly associated with increased IHD risk (hazard ratio [HR] = 1.07, 95% confidence interval [CI] = 0.77–1.48;p= 0.690). The 10-year OS rate was 98.0%, and postoperative RT remained an independent predictor of improved survival (HR = 0.47, 95% CI = 0.28–0.79;p= 0.004). Conclusions: Postoperative RT did not increase the long-term risk of IHD but was associated with improved OS in patients with DCIS. These findings provide population-based evidence supporting the cardiac safety and oncologic efficacy of postoperative RT, while recognizing that unmeasured differences in health behavior or medical care utilization could have contributed to the observed survival benefit.
背景：乳腺导管原位癌（DCIS）患者接受肿块切除术后进行放射治疗（RT）可降低局部区域复发风险。然而，放疗与缺血性心脏病（IHD）之间的潜在关联仍不明确。本研究基于韩国国民健康保险服务（NHIS）的真实世界数据，通过全国性队列研究评估了DCIS患者术后放疗对IHD风险及总生存期（OS）的长期影响。方法：从NHIS理赔数据库中筛选2003年至2020年间接受保乳手术的DCIS确诊女性。排除浸润性乳腺癌、年龄低于20岁、有IHD病史或吸烟史、体重指数（BMI）数据缺失的患者。采用多变量Cox回归模型评估术后放疗与IHD发生率及OS的关联，并对主要心血管危险因素进行校正。结果：在4633例符合条件患者中（放疗组2778例，非放疗组1855例），中位随访时间为86.1个月，两组基线特征均衡，心血管危险因素无显著差异。共126例（3.4%）发生IHD，10年累积发生率为4.7%。高龄、高血压和高脂血症是IHD的独立危险因素，而术后放疗与IHD风险增加无显著关联（风险比[HR]=1.07，95%置信区间[CI]=0.77–1.48；p=0.690）。10年OS率为98.0%，术后放疗仍是改善生存的独立预测因素（HR=0.47，95% CI=0.28–0.79；p=0.004）。结论：术后放疗未增加DCIS患者的长期IHD风险，且与OS改善相关。这些基于人群的研究结果为术后放疗的心脏安全性和肿瘤疗效提供了证据，但需注意未测量的健康行为或医疗资源使用差异可能对观察到的生存获益产生影响。
肿瘤(癌症)患者之家