207 Does Adjuvant Radiotherapy Lead to Increased Survival in Patients with Adenoid Cystic Carcinoma of the Breast? a Systematic Review and Meta-Analysis

Abstract

Abstract Aim Adenoid cystic carcinoma (ACC) of the breast accounts for approximately 0.1% of all breast tumours (Zhang et al, 2021). The aim of this systematic review and meta-analysis was to determine whether adjuvant radiotherapy provides an additional benefit when compared to surgery alone in terms of overall survival in patients with ACC. Method A total of 3,330 records were identified and screened following database, conference proceedings, and currently registered studies search. Data from 5 case series was extracted. A random-effects meta-analysis of overall survival (OS) at 1, 2, 3-, 4-, 5- and 10-years post-intervention was performed. Results Adjuvant radiotherapy and surgery alone led to similar OS at all points post-intervention. For instance, 5-year survival following use of adjuvant radiotherapy was 92.8% (95% CI: 90.5%-94.7%), compared to 88.7% (95% CI: 81.9%-94.2%) with surgery alone. The confidence intervals overlap, which was the case for all points post-intervention. Conclusions Similar OS for both adjuvant radiotherapy and surgery alone (and overlapping confidence intervals), suggest the former may not provide an additional benefit in terms of OS in patients with ACC. Considering the negative side effects of radiotherapy, it could be argued that surgery alone should be used for the treatment ACC. However, this conclusion is hindered by the low number of studies included in this meta-analysis and their low level of evidence. This could be attributed to the low incidence of ACC. Further data should be collected to more reliably determine their optimal treatment.