Circulating tumor cells as prognostic and predictive markers in metastatic breast cancer patients receiving first-line systemic treatment
1 Department of Hematopathology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA
2 Department of Molecular and Clinical Oncology and Endocrinology, University of Naples Federico II, via Pansini 5, 80131 Naples, Italy
3 Currently: Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
4 Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA
5 Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA
6 Currently: Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Via Maroncelli 40, 47014 Meldola (FC), Italy
7 Currently: Department of Medical Oncology, School of Medicine, Comenius University, Klenova 1, Bratislava 833 10, Slovakia
8 Laboratory Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA
9 Department of Medical Oncology, Fox Chase Medical Center, 333 Cottman Avenue, Rm 315, Philadelphia, PA 19111-2497, USA
Breast Cancer Research 2011, 13:R67 doi:10.1186/bcr2907Published: 15 June 2011
Circulating tumor cells (CTCs) represent an independent predictor of outcome in patients with metastatic breast cancer (MBC). We assessed the prognostic impact of CTCs according to different first-line systemic treatments, and explored their potential predictive value in MBC patients.
We retrospectively evaluated 235 newly diagnosed MBC patients, treated at the University of Texas MD Anderson Cancer Center. All patients had a baseline CTC assessment performed with CellSearch®. Progression-free survival and overall survival were compared with the log-rank test between groups, according to CTC count (< 5 vs. ≥ 5) and type of systemic therapy. We further explored the predictive value of baseline CTCs in patients receiving different treatments.
At a median follow-up of 18 months, the CTC count was confirmed to be a robust prognostic marker in the overall population (median progression-free survival 12.0 and 7.0 months for patients with CTC < 5 and ≥ 5, respectively; P < 0.001). Conversely, in patients with human epidermal growth factor receptor-2-overexpressed/amplified tumors receiving trastuzumab or lapatinib, the baseline CTC count was not prognostic (median progression-free survival 14.5 months for patients with CTC < 5 and 16.1 months for those with CTC ≥ 5; P = 0.947). Furthermore, in patients with human epidermal growth factor receptor-2 normal tumors, a baseline CTC count ≥ 5 identified subjects who derived benefit from more aggressive treatments, including combination chemotherapy and chemotherapy plus bevacizumab.
This analysis suggests that the prognostic information provided by CTC count may be useful in patient stratifications and therapeutic selection, particularly in the group with positive CTCs, in which various therapeutic choices may procure differential palliative benefit.