Neoadjuvant chemotherapy (NACT) for early breast cancer can make breast-conserving surgery more feasible and might be more likely to eradicate micrometastatic disease than might the same chemotherapy given after surgery. We investigated the long-term benefits and risks of NACT and the influence of tumour characteristics on outcome with a collaborative meta-analysis of individual patient data from relevant randomised trials. We obtained information about prerandomisation tumour characteristics, clinical tumour response, surgery, recurrence, and mortality for 4756 women in ten randomised trials in early breast cancer that began before 2005 and compared NACT with the same chemotherapy given postoperatively. Primary outcomes were tumour response, extent of local therapy, local and distant recurrence, breast cancer death, and overall mortality. Analyses by intention-to-treat used standard regression (for response and frequency of breast-conserving therapy) and log-rank methods (for recurrence and mortality). Patients entered the trials from 1983 to 2002 and median follow-up was 9 years (IQR 5-14), with the last follow-up in 2013. Most chemotherapy was anthracycline based (3838 [81%] of 4756 women). More than two thirds (1349 [69%] of 1947) of women allocated NACT had a complete or partial clinical response. Patients allocated NACT had an increased frequency of breast-conserving therapy (1504 [65%] of 2320 treated with NACT vs 1135 [49%] of 2318 treated with adjuvant chemotherapy). NACT was associated with more frequent local recurrence than was adjuvant chemotherapy: the 15 year local recurrence was 21·4% for NACT versus 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). No significant difference between NACT and adjuvant chemotherapy was noted 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). Tumours downsized by NACT might have higher local recurrence after breast-conserving therapy than might tumours of the same dimensions in women who have not received NACT. Strategies to mitigate the increased local recurrence after breast-conserving therapy in tumours downsized by NACT should be considered-eg, careful tumour localisation, detailed pathological assessment, and appropriate radiotherapy. Cancer Research UK, British Heart Foundation, UK Medical Research Council, and UK Department of Health.

The aim of this multicenter randomized trial was to assess the efficacy and safety of sentinel lymph node (SLN) biopsy compared with axillary lymph node dissection (ALND). All studies on SLN biopsy in breast cancer report a variable false negative rate, whose prognostic consequences are still unclear. From May 1999 to December 2004, patients with breast cancer ≤3 cm were randomly assigned to receive SLN biopsy associated with ALND (ALND arm) or SLN biopsy followed by ALND only if the SLN was metastatic (SLN arm). The main aim was the comparison of disease-free survival in the 2 arms. A total of 749 patients were randomized and 697 were available for analysis. SLNs were identified in 662 of 697 patients (95%) and positive SLNs were found in 189 of 662 patients (28.5%). In the ALND group, positive non-SLNs were found in 18 patients with negative SLN, giving a false negative rate of 16.7% (18 of 108). Postoperative side effects were significantly less in the SLN group and there was no negative impact of the SLN procedure on psychologic well being. At a median follow-up of 56 months, there were more locoregional recurrences in the SLN arm, and the 5-year disease-free survival was 89.9% in the ALND arm and 87.6% in the SLN arm, with a difference of 2.3% (95% confidence interval: −3.1% to 7.6%). However, the number of enrolled patients was not sufficient to draw definitive conclusions. SLN biopsy is an effective and well-tolerated procedure. However, its safety should be confirmed by the results of larger randomized trials and meta-analyses.