Overall Survival and Related Clinicopathologic Features to Identify Low-Risk Patients With Early Breast Cancer Suitable For Radiation Therapy Omission After Conservative Surgery: A Meta-Analysis.

Post-operative radiation therapy (PORT) following breast-conserving surgery (BCS) has become a conventional care for early-stage breast cancer (EBC). This meta-analysis aimed to compare overall survival (OS) between patients receiving PORT and those not receiving PORT and to identify clinicopathologic features of low-risk patients with EBC who may be suitable for PORT omission after BCS with respect to OS. Comparative studies investigating PORT versus non-PORT in EBC patients after BCS were included, focusing on hazard ratio (HRs) for OS. Medline, Embase, and the Cochrane Central Library were searched from First January 2014 to First January 2025. A meta-analysis was performed to determine the HR for OS between PORT and non-PORT groups. Subgroup analyses were conducted to identify potential clinicopathologic features associated with low-risk patients suitable for PORT omission. A total of 28 studies (2 randomized controlled trials and 26 retrospective cohort studies) with 589,508 patients were included in the final analysis. According to the meta-analysis, patients with EBC derived an OS benefit from PORT (pooled HR = 0.60 [95% CI, 0.55-0.65]). Subgroup analyses identified clinicopathologic features associated with low-risk patients suitable for PORT omission. This systematic review and meta-analysis demonstrated that PORT is associated with improved OS in patients with EBC following BCS. However, certain clinicopathologic features, including age 65-70 years, progesterone receptor (-), luminal B subtype, triple-negative breast cancer, and low-risk 21-gene recurrence score, were identified as potential low-risk factors in patients who may be considered for PORT omission.