High prognostic significance of residual disease after neoadjuvant chemotherapy: a retrospective study in 710 patients with operable breast cancer.

ABSTRACT

Prognostic factors are used to help clinical decision-making in selecting the appropriate treatment for individual patients. The purpose of this retrospective study was to identify one or more factors associated with overall survival (OS) and disease-free survival (DFS), in 710 patients with operable breast cancer, subjected to neoadjuvant chemotherapy followed by surgery, radiotherapy and adjuvant treatments. At a median follow-up of 7.6 years, univariate analysis showed that pathological complete response (pCR) was significantly related to survival (p < 0.003), as well as accepted prognostic factors, as SBR and MSBR grades, hormonal receptors or node involvement at surgery, who remained significant in our study (p < 0.001). The revised Nottingham prognostic index (NPI) and related indices (BGI, MNPI and MBGI) were also significantly associated to survival (p < 0.003). In multivariate analysis, node involvement and MSBR grade remained prognostic factors for OS and DFS (p < 0.0003 and p < 0.02, respectively). The MNPI and pCR were significantly related with OS (p = 0.04) and pts with hormonal receptor-positive tumours had a better DFS than others (p = 0.004). Among all clinical and pathological parameters, axillary dissection after neoadjuvant chemotherapy is still important to determine node involvement, a major prognostic factor. Moreover, MSBR grade seemed to be more accurate and predictive of long-term outcome than the standard SBR grade. It is concluded that, outside any other 'biological' factor, residual disease in breast and nodes must be strongly considered after an induction chemotherapy so as to choose adjuvant treatment for the individual patient.