Department of Radiation Oncology, Toronto, ON, Canada; Institute for Clinical Evaluative Sciences, Toronto, ON, Canada; Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada.
Department of Pathology, Toronto, ON, Canada.
Breast. 2018 Feb;37:181-186. doi: 10.1016/j.breast.2017.07.002. Epub 2017 Aug 3.
Radiation therapy (RT) after breast-conserving surgery (BCS) for Ductal Carcinoma in Situ (DCIS) halves the risk of local recurrence (LR). The omission of RT is often supported by the paradigm that patients who develop LR can be salvaged with further breast-conserving therapy leading to higher rates of breast preservation and improved quality of life. However, population-based, long-term rates of breast preservation in women treated by upfront BCS ± RT are unknown.
Women diagnosed with pure DCIS from 1994 to 2003 treated with BCS ± RT in Ontario were identified. Median follow-up is 12 years. The development and treatment of LR and contralateral breast cancers were determined by administrative databases with validation. The 10-year mastectomy-free survival was calculated using the Kaplan-Meier method. The impact of RT on breast preservation was determined by propensity-adjusted cox proportional hazards model.
The cohort includes 3303 women with DCIS; 1649 (50%) underwent BCS alone, 1654 (50%) underwent BCS + RT. Women treated by BCS alone were more likely to develop a LR compared to those treated by upfront BCS + RT (20.8% versus 15.5%, p < 0.001). Mastectomy was used to treat LR in 57.4% (197/343) of women who recurred after BCS alone and 67.6% (174/257) of those who recurred after BCS + RT. Women treated with upfront BCS + RT had higher rates of bilateral breast preservation at 10 years compared to those treated by BCS alone (87.3% vs.82.7%, p = 0.0096).
Local Recurrence after BCS alone does not favor breast preservation.
保乳手术后（BCS）进行放射治疗（RT）可使导管原位癌（DCIS）的局部复发（LR）风险降低一半。经常省略 RT 的原因是，那些发生 LR 的患者可以通过进一步的保乳治疗来挽救，从而提高保乳率并改善生活质量。但是，对于接受 BCS 治疗的患者，基于人群的长期保乳率尚不清楚。
在安大略省，从 1994 年至 2003 年，对诊断为纯 DCIS 的女性进行了 BCS 治疗±RT 治疗。中位随访时间为 12 年。通过行政数据库确定 LR 和对侧乳腺癌的发展和治疗情况，并进行了验证。使用 Kaplan-Meier 方法计算 10 年无乳房切除术生存率。通过倾向调整的 Cox 比例风险模型确定 RT 对保乳的影响。
该队列包括 3303 名患有 DCIS 的女性；1649 名（50％）接受了单纯 BCS，1654 名（50％）接受了 BCS+RT。单独接受 BCS 治疗的女性比接受直接 BCS+RT 的女性更有可能发生 LR（20.8％比 15.5％，p<0.001）。在单独接受 BCS 治疗的患者中，有 57.4％（197/343）的 LR 患者需要进行乳房切除术，而在接受 BCS+RT 治疗的患者中，有 67.6％（174/257）的患者需要进行乳房切除术。与单独接受 BCS 治疗的患者相比，直接接受 BCS+RT 治疗的患者在 10 年内双侧乳房保留率更高（87.3％对 82.7％，p=0.0096）。
单独接受 BCS 治疗后的局部复发不利于保乳。
