Researchers investigated the long-term benefits and risks of neoadjuvant chemotherapy (NACT) and the influence of tumour characteristics on the outcome with a collaborative meta-analysis of individual patient data from relevant randomised trials. After breast-conserving therapy, tumours downsized by NACT could have a higher local recurrence than might tumours of the same dimensions in women who did not receive NACT. Strategies to mitigate the increased local recurrence after breast-conserving therapy in tumours downsized by NACT ough to be considered-eg, careful tumour localization, detailed pathological assessment, and appropriate radiotherapy.

Methods

• Data was collected regarding prerandomisation tumour characteristics, clinical tumour response, surgery, recurrence, and mortality for 4756 women in 10 randomised trials in early breast cancer that began before 2005, followed by a comparison of NACT with the same chemotherapy given postoperatively.
• Tumour response, extent of local therapy, local and distant recurrence, breast cancer death, and overall mortality were the primary outcomes.
• The researchers performed this analyses by intention-to-treat using standard regression (for response and frequency of breast-conserving therapy) and log-rank methods (for recurrence and mortality).

Results

• Between 1983 to 2002, patients entered the trials and median follow-up was 9 years (IQR 5-14), with the last follow-up being conducted in 2013.
• As per findings, most chemotherapy was anthracycline based (3838 [81%] of 4756 women).
• A complete or partial clinical response was observed in more than two thirds (1349 [69%] of 1947) of women allocated NACT.
• An increased frequency of breast-conserving therapy was found in patients allocated NACT (1504 [65%] of 2320 treated with NACT vs 1135 [49%] of 2318 treated with adjuvant chemotherapy).
• NACT displayed correlation with more frequent local recurrence than was adjuvant chemotherapy: The 15 year local recurrence was 21·4% for NACT vs 15·9% for adjuvant chemotherapy (5·5% increase [95% CI 2·4-8·6]; rate ratio 1·37 [95% CI 1·17-1·61]; p=0·0001).
• The researchers noted no significant difference between NACT and adjuvant chemotherapy for distant recurrence (15 year risk 38·2% for NACT vs 38·0% for adjuvant chemotherapy; rate ratio 1·02 [95% CI 0·92-1·14]; p=0·66), breast cancer mortality (34·4% vs 33·7%; 1·06 [0·95-1·18]; p=0·31), or death from any cause (40·9% vs 41·2%; 1·04 [0·94-1·15]; p=0·45).