Surgical treatment of primary breast cancer in the neoadjuvant setting

Background: Neoadjuvant chemotherapy (NACT) is a standard treatment option for primary operable breast cancer when adjuvant chemotherapy is indicated. Methods: This article reviews the use of NACT in breast cancer treatment. Results: Pathological complete response (pCR) rates of up to 60 per cent have been reached for certain breast cancer subgroups. Patients achieving a pCR have a lower locoregional recurrence rate. Nevertheless, the rate of breast-conserving surgery seems to be stable at around 65-70 per cent, although more than 80 per cent of patients respond to NACT. The risk of local relapse does not appear to be higher after NACT, which supports the recommendation to operate within the new margins, as long as there is no tumour in the inked area of the surgical specimen. However, tumours do not shrink concentrically and the re-excision rate is higher after NACT. Mastectomy rates for lobular carcinomas remain high irrespective of tumour response. The role of sentinel lymph node biopsy (SLNB) in the context of NACT has been studied in recent years, and it is not yet completely clear which type of axillary staging is the most suitable. SLNB before NACT in clinically node-negative patients has been the preferred option. However, this practice is currently changing, and it seems advisable to have the SLNB after NACT to reduce the risk of a false-negative SLNB. Conclusion: Overall, patients do benefit from NACT, especially those with human epidermal growth factor receptor 2-positive and triple-negative breast cancer, but surgical/local procedures need to be adapted.