Circulating Tumor Cells After Neoadjuvant Chemotherapy in Stage I-III Triple-Negative Breast Cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) is characterized by a lack of estrogen and progesterone receptor expression and HER-2 gene amplification. Circulating tumor cells (CTCs) can be identified in 25 % of nonmetastatic breast cancer patients, and the identification of ≥1 CTC predicts outcome. This study was designed to determine whether CTCs present after neoadjuvant chemotherapy (NACT) predicted worse outcome in nonmetastatic TNBC patients.

METHODS: CTCs were assessed in 57 TNBC patients with nonmetastatic TNBC after the completion of NACT. CTCs (per 7.5 ml blood) were identified using the Cell Search(®) System (Janssen). Log-rank test and Cox regression analysis were applied to establish the association of CTCs with relapse-free (RFS) and overall survival (OS).

RESULTS: Median follow-up was 30 months, and mean age was 53 years. Fifty-four patients (95 %) had >2-cm tumors, 42 (84 %) were nuclear grade 3, and 42 (74 %) had positive axillary lymph nodes. One or more CTC was identified in 30 % of patients. CTC presence was not associated with primary tumor size, high grade, or lymph node positivity. Multivariate analysis demonstrated that detection of ≥1 CTC predicted decreased RFS (log-rank P = 0.03, HR 5.25, 95 % CI 1.34-20.56) and OS (log-rank P = 0.03, HR 7.04, 95 % CI 1.26-39.35).

CONCLUSIONS: One or more CTCs present after NACT predicted relapse and survival in nonmetastatic TNBC patients. This information would be helpful in future clinical trial design of adjuvant treatments for TNBC patients who are at risk for relapse after completing NACT.