Aims
Several overseas publications have reported recent changes in the rate of mastectomy for invasive breast cancer (1-6). We sought to identify any variation in breast cancer management in Victoria via a linkage between the Victorian Admitted Episode Dataset (VAED) and the Victorian Cancer Registry (VCR).
Methods
A retrospective cohort study was performed on 29,422 female patients registered in the VCR, with a diagnosis of primary (invasive) breast cancer within the study timeframe (4January 2000 to 31 December 2010). Socio-demographic and clinico-pathologic features were assessed for their impact on primary surgery, chemotherapy, and breast reconstruction.
Results
There were 26,554 women who underwent a definitive local procedure (DLP). The first DLP was mastectomy in 8,817 women. Of these, 8,145 underwent a unilateral mastectomy and 672 underwent a bilateral mastectomy. The DLP was wide local excision (WLE) in 17,737 women. The 90-day mastectomy rate was 38% in 2000 and 40% in 2010. Two hundred and ninety-seven women (1.1%) underwent a contra-lateral ‘prophylactic’ mastectomy. The mean length of stay was 4.1 days for mastectomy and 3.2 days for WLE. Adjuvant chemotherapy was administered to 5,298 women (19%). Neo-adjuvant chemotherapy (NACT) was administered to 534 women (1.9%). Following NACT, 406 women had a mastectomy (70.0% of DLPs). Axillary clearance as a percentage of first DLP, declined over the study timeframe, from 80% in 2000 (n=1,418) to 37% in 2010 (n=935). In total, 2,078 women had 3,574 admissions for definitive or staged breast reconstruction procedures. Bilateral mastectomy increased from a total of 145 admissions in 2000 to 549 admissions in 2010.
Conclusions
We conclude that the 90-day mastectomy rate remained constant between 2000 and 2010. The use of chemotherapy (adjuvant and neo-adjuvant), breast reconstruction, and bilateral mastectomy increased markedly, and the use of axillary clearance decreased over the study timeframe.