The impact of advanced oncoplastic surgery on breast-conserving surgery rates: A retrospective cohort study of 3,875 breast cancer procedures at a tertiary referral centre

Introduction: As the treatment of breast cancer advances, the focus has shifted from solely improving oncological endpoints to a greater weight being placed on cosmetic and psychological outcomes. The advent of advanced oncoplastic techniques allows for successful breast-conserving surgery (BCS) to patients who otherwise would have required a mastectomy. The aim of this study is to ascertain if the adoption of these procedures has assisted in the reduction of mastectomies performed. Methods: A dataset of all breast cancer procedures based upon coding between April 2016 and July 2023 was evaluated, categorising procedures into: BCS, mastectomy, oncoplastic BCS and total reconstructions. R-Studio Software 4.3.1 (®) was used to explore statistical analysis and data visualisation. Registered as a clinical services evaluation study (Project ID: 14649). Results: During the period stated, 3875 index breast cancer procedures were recorded (sample size = 3638 patients). The BCS rate increased from 66.2 % in 2016 to 80.7 % in 2023. Using a linear regression model, the BCS rate demonstrates an increase of 2.1 % each year (coefficient = 2.12, p-value = 0.0069). Concurrently, the rate of oncoplastic BCS increased from 10.5 % to 22.9 % (coefficient = 2.14, p-value = 0.00017). Using Pearson's product-moment, a positive correlation between these two variables is seen (coefficient = 0.86, p-value = 0.0056). Conclusion: Having reviewed 3875 index breast cancer procedures over the past eight years, the BCS rate has shown a statistically significant increase and a positive correlation with the oncoplastic BCS rate. This suggests oncoplastic surgery has helped to reduce the rates of mastectomy at the centre.