Good clinical response of breast cancers to neoa uvant chemoendocrine therapy is associated with improved overall survival

Background: We present extended follow-up from a prospective randomised trial evaluating the role of neoadjuvant chemoendocrine therapy in the treatment of operable breast cancer. Patients and methods: 309 women were randomised to primary surgery followed by eight cycles of adjuvant mitoxantrone, methotrexate with tarnoxifen (2MT) or 2MT with mitomycin-C (3MT) versus the same regimen for four cycles before followed by four cycles after surgery. For this analysis the median follow-up of patients was 112 months. Results: After 10 years follow-up there is still no statistically significant difference in disease-free survival (DFS) (71% versus 71%) or overall survival (OS) (63% versus 70%) when comparing adjuvant versus neoadjuvant treatment, respectively. Of 144 evaluable patients in the neoadjuvant arm, 74 achieved a good clinical response and 70 patients achieved a poor clinical response. Good responders had a superior DFS (80% versus 64%, P=0.01) and OS (77% versus 63%, P=0.03) compared to poor responders. Conclusions: At 10 years, neoadjuvant and adjuvant treatment continue to have equivalent OS and DFS. Good clinical response to neoadjuvant chemotherapy is associated with superior DFS and OS. This supports the use of clinical response of primary breast cancer to neoadjuvant therapy as a surrogate marker of survival benefit.