More Breast-Conserving Surgery in Australia in T2 Breast Cancers Over the Last 20 Years

Background and Purpose: Guidelines on surgical management of T2-sized breast cancers (T2BC) (≥ 2cm and ≤ 5cm) specify breast-conserving surgery (BCS) or mastectomy as treatment options, without particular recommendation. There is currently no published data exploring the trend of BCS vs mastectomy for T2BC over time. Given advancements in surgical techniques and medical therapies, we hypothesise more BCS is being performed over mastectomy now, compared to previously. Exploring the rationale(s) for this may help further clarify guidelines. Methods: The number of BCS and mastectomies for T2BC in Australia and our institution, the Royal Adelaide Hospital (RAH), during 2000-2021, was analysed using the BreastSurgANZ Quality Audit. The data was also stratified by surgical patients treated with neoadjuvant chemotherapy and without. Results: 75,312 patients in Australia underwent mastectomy or BCS between 2000-2021 for T2BC. The ratio of mastectomy to BCS performed from 2000-2010 reduced by approximately 40% compared to 2019-2021 (1.23 vs 0.82). This trend is mirrored by our institution with a 94% reduction in ratio of mastectomy to BCS (2.27 vs 0.82) for the same time periods. A Chi-square test performed between years and rate of mastectomy showed a statistically significant relationship (χ2(3) =331.858; p<0.001). The trend persisted even after excluding neoadjuvant chemotherapy patients. Conclusions: The shift from mastectomy to BCS for T2BC is multifactorial. Surgeons are increasingly performing BCS with oncoplastic techniques over standard lumpectomy or mastectomy for early breast cancer with the literature showing improved overall survival.1 Breast surgery teams are also tolerating narrower margins in BCS without higher risk of recurrence or mortality.2 Improved screening and diagnostic techniques, and adjuvant treatment result in surgery patients surviving longer and living with the legacy of their scars. Thus, patient satisfaction and body image may also play a role given earlier and younger detection of breast cancer. References: 1. De La Cruz L, Blankenship SA, Chatterjee A, Geha R, Nocera N, Czerniecki BJ, Tchou J, Fisher CS (2016) Outcomes After Oncoplastic Breast-Conserving Surgery in Breast Cancer Patients: A Systematic Literature Review. Ann Surg Oncol 23 (10):3247-3258. doi:10.1245/s10434-016-5313-1 2. Tyler S, Truong PT, Lesperance M, Nichol A, Baliski C, Warburton R, Tyldesley S (2018) Close Margins Less Than 2 mm Are Not Associated With Higher Risks of 10-Year Local Recurrence and Breast Cancer Mortality Compared With Negative Margins in Women Treated With Breast-Conserving Therapy. Int J Radiat Oncol Biol Phys 101 (3):661-670. doi:10.1016/j.ijrobp.2018.03.005