Recurrence rates in breast cancer have dramatically decreased over the past 30 years. A consequence is that adjuvant clinical trials are now larger and longer, some enrolling 5000 to 10 000 patients. Such trials are not sustainable. Their usefulness is diminished by the increasing dynamism of cancer biology, which can make any trial’s results less relevant if too long a time passes before reporting. Neoadjuvant clinical trials have the potential to mitigate these problems if their short-term results predict longer-term clinical benefits. If an early read regarding an experimental therapy’s antitumor effect fails to accurately predict event-free or overall survival, then the approach will not be as useful.
Berry DA, Hudis CA. Neoadjuvant Therapy in Breast Cancer as a Basis for Drug Approval. JAMA Oncol. 2015;1(7):875-876. doi:10.1001/jamaoncol.2015.1293