A paper published in Lancet Oncology reported long-term outcomes after chemotherapy given before surgery (neoadjuvant chemotherapy or NACT) compared to the same chemotherapy given after surgery (adjuvant chemotherapy). NACT is increasingly used to treat women with early breast cancer and can be helpful for a number of reasons.
This Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) meta-analysis included individual patient data from over 4500 women with early (i.e. operable) breast cancer entered in 10 randomised trials from across the world that compared NACT with adjuvant chemotherapy.
The study found that NACT and adjuvant chemotherapy were equally effective in preventing the development of metastatic disease and death from breast cancer, and NACT allowed more women to have breast-conserving therapy than in the adjuvant chemotherapy group.
However, the risk of cancer recurring in the breast or adjacent lymph glands (local recurrence) was somewhat higher with NACT compared to adjuvant chemotherapy (21.4% vs 15.6% respectively by year 15, a 5.5% increase). The increase in local recurrence risk was highest in the two trials that sometimes omitted surgery after a good response to NACT but an increased risk was also seen in trials where breast surgery was performed irrespective of response to NACT.
The response rates achieved with NACT varied considerably according to the chemotherapy regimens used, 80% of them were anthracycline based. But, the increase in local recurrence was not much affected by choice of chemotherapy. Dr Paul McGale, lead author of the study commented “We saw quite big differences in response rates and use of breast-conserving therapy between trials but the higher risk of local recurrence was no different.”The most likely explanation for the increased risk of local recurrence is the wider use of breast-conserving therapy in women receiving NACT.
Professor David Dodwell, a clinical oncologist and co-author of the study, added “Since the trials in this meta-analysis were performed, treatments for early breast cancer have improved, but care still needs to be taken to minimise the risk of local recurrence after NACT, for example by careful tumour localisation, detailed pathological assessment, and appropriate radiotherapy.”