Detection of disseminated tumor cells in bone marrow predict late recurrences in operable breast cancer patients.

ABSTRACT

BACKGROUND: Operable breast cancer patients may experience late recurrences because of reactivation of dormant tumor cells within the bone marrow (BM). Identification of patients who would benefit from extended therapy is therefore needed. METHODS: BM samples obtained pre- and post-surgery were previously analysed for presence of disseminated tumor cells (DTC) by a multimarker mRNA quantitative reverse-transcription PCR assay. Updated survival analyses were performed on all patient data (n = 191) and in a subgroup of patients alive and recurrence-free after 5 years (n = 156). DTC data were compared to the mitotic activity index (MAI) of the primary tumors. Median follow-up time was 15.3 years. RESULTS: Among the 191 patients, 49 (25.65%) experienced systemic relapse, 24 (49%) within 5-18 years after surgery. MAI and pre- and post-operative DTC status had significant prognostic value based on Kaplan-Meier analyses and multiple Cox regression in the overall patient cohort. With exclusion of patients who relapsed or died within 5 years from surgery, only pre-operative DTC detection was an independent prognostic marker of late recurrences. High MAI (≥10) did not predict late recurrences or disease-specific mortality. CONCLUSION: Pre-operative DTC detection, but not MAI status, predicts late recurrences in operable breast cancer.