Yang Zejian, Li Kunlong, Qiu Pei, Ma Yifei, Wang Bin, Yan Yu, Meng Du, Feng Chen, Ren Yu, Li Yijun, Li Pingping, Zhou Can
Department of Breast Surgery, First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta Western Rd., Xi'an, 710061, Shaanxi Province, China; Xi'an Jiaotong University Health Science Center, 76 Yanta Western Rd., Xi'an, 710061, Shaanxi Province, China.
Department of Breast Surgery, First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta Western Rd., Xi'an, 710061, Shaanxi Province, China.
Breast. 2021 Dec;60:287-294. doi: 10.1016/j.breast.2021.11.015. Epub 2021 Nov 22.
Radiotherapy after breast-conserving surgery (BCS) is not always necessary in older women staged T1N0M0 with low-risk invasive breast cancer, but few studies have concluded the detailed tumor size as a reference for avoiding radiotherapy. The study was conducted to explore and identify the optimal cutoff tumor size.
The study population was from the Surveillance, Epidemiology, and End Results (SEER) database in 2010-2016. Propensity score matching was used to balance the confounders between groups. Predictors associated with survival were analyzed by Kaplan-Meier, X-tile, Cox proportional hazards model and competing risk model.
A total of 52049 women and 3846 deaths were included in the cohort with a median follow-up of 34 months. Based on the cutoff value determined by X-tile analysis, the study population were divided into small tumor group (≤14 mm in diameter) and large tumor group (>14 mm in diameter). Small tumors and radiotherapy were correlated with better breast cancer-specific survival (BCSS). In subgroup analysis, the absolute benefit of BCSS in 6 years attributed to radiotherapy was only 0.90% (RT vs. non- RT:98.77% vs. 97.87%) for patients with small tumors but up to 3.33% (RT vs. non- RT:97.10% vs. 93.77%) for those with large tumors.
Small tumors and adjuvant radiotherapy were associated with improved long-term prognosis, and 14 mm in diameter was the cutoff tumor size of omitting radiotherapy for patients aged 65 or older with T1N0M0 stage, ER+ and HER2-breast carcinoma after BCS.
对于患有低风险浸润性乳腺癌的T1N0M0期老年女性，保乳手术后（BCS）并非总是需要进行放疗，但很少有研究得出详细的肿瘤大小作为避免放疗的参考。本研究旨在探索和确定最佳的肿瘤大小临界值。
研究人群来自2010 - 2016年的监测、流行病学和最终结果（SEER）数据库。采用倾向评分匹配来平衡组间的混杂因素。通过Kaplan - Meier、X - tile、Cox比例风险模型和竞争风险模型分析与生存相关的预测因素。
该队列共纳入52049名女性，3846例死亡，中位随访时间为34个月。根据X - tile分析确定的临界值，将研究人群分为小肿瘤组（直径≤14mm）和大肿瘤组（直径>14mm）。小肿瘤和放疗与更好的乳腺癌特异性生存（BCSS）相关。在亚组分析中，对于小肿瘤患者，放疗在6年中对BCSS的绝对获益仅为0.90%（放疗组与非放疗组：98.77% vs. 97.87%），而对于大肿瘤患者则高达3.33%（放疗组与非放疗组：97.10% vs. 93.77%）。
小肿瘤和辅助放疗与改善长期预后相关，对于65岁及以上T1N0M0期、ER +和HER2 -的乳腺癌患者，保乳手术后直径14mm是省略放疗的肿瘤大小临界值。
