Circulating tumour cells in locally advanced breast cancer

A prospective study was conducted to determine the value of changes in circulating tumour cell (CTC) levels prior to and after the first cycle of neoadjuvant treatment in early prediction of pathologic response in locally advanced breast cancer (LABC). Two blood samples were obtained from 72 eligible LABC patients to isolate and enumerate CTCs before neoadjuvant chemotherapy started on day 1, and on day 21, immediately before second cycle administration.

Sixty patients (83.3%) had <1 CTC in the first sample and response rates in this cohort were pathologic complete response (PCR) in 2 patients (5%), partial response (PR) in 35 (87.5%), stable disease (SD) in 2 (5%) and progressive disease (PD) in 1 (2.5%). Twelve patients (16.7%) had >2 CTCs in the first sample; these patients were more likely to have triple negative tumours. All 12 had fewer CTCs in the second sample. Response rates in this second cohort of 12 patients were PCR in 4 (34%), PR in 6 (50%), SD in 1 (8%) and PD in 1 (8%). PCR rate was markedly better in this second cohort (p<0.0042; OR 14.5, 95% CI 2.3-92).

This study suggests that the presence of CTCs prior to neoadjuvant therapy might be a predictor of response to this therapy.