The use of neoadjuvant systemic therapies in breast cancer in Australia and New Zealand: Breast Surgeons of Australia and New Zealand quality audit

Abstract

Background: Breast surgeons must maintain contemporary knowledge regarding appropriate referral for neoadjuvant chemotherapy (NACT) in breast cancer (BC) patients. To date, the greatest benefit is seen in stage II-III HER2-enriched and triple negative breast cancers (TNBC). This study is the first audit of use of NACT in Australia and New Zealand to stratify data by BC biological subtype.

Methods: Prospective data from 116,745 patients between 2010 and 2019 was provided by the Breast Surgeons of Australia and New Zealand (BreastSurgANZ) Quality Audit (BQA) of Breast Cancer Care. Annual rates of NACT use were determined and change across time analysed with fractional regression. Data from 2018 to 2019 were combined and stratified by biological subtype (LumA, LumB HER2-neg, LumB HER2-pos, HER2 enriched, TNBC, Other basal-like), and age (<50, 51-74, and ≥75 years) and compared using negative binomial regression.

Results: The use of NACT increased annually (OR 1.26, P < 0.001), and the use of additional adjuvant chemotherapy (ACT) decreased (OR 0.78, P < 0.001). A significantly greater use of NACT was noted in patients with TNBC and HER2+ BC, and in all patients aged <50 years compared with older ages (P < 0.001), regardless of biological subtype.

Conclusion: Increased uptake of NACT and decreased use of additional ACT is in keeping with progressive change in practice in response to contemporary evidence. Expansion of BQA data fields related to use of NACT, and detailed audit of NACT rates in Stage II-III TNBC and HER2 enriched BC will allow accurate determination of quality of practice in ANZ.

Keywords: Australia; New Zealand; audit; breast cancer; herceptin; neo-adjuvant chemotherapy; quality indicator.