The Prognostic Value of Circulating Tumor Cells in Primary Breast Cancer Prior to any Systematic Therapy: A Systematic Review.

BACKGROUND: Numerous studies have inclined the upstanding role of circulating tumor cells (CTC) in management of cancer, particularly the ones in association with primary tumor metastases.

OBJECTIVE: The overall aim of the present study was to investigate whether CTCs may serve as a clinical prognostic marker for survival in primary breast cancer.

METHOD: Articles Published from June 2011 to July 2017 in PubMed, EMBase, and Cochrane library databases were thoroughly screened for selecting the ones mitting the inclusion criteria.

RESULT: Studies applying CellSearch ® method demonstrated the risk ratios (RR) of 2.51 (95% CI: 1.78- 3.54), 3.98 (95% CI: 2.28- 6.95), 5.59 (95% CI: 3.29- 9.51), and 3.38 (95% CI: 1.88- 6.06) for death rate and relapse rates of 2.06 (95% CI: 1.71- 2.47), 3.89 (95% CI: 2.43- 6.23), 5.41 (95 % CI: 2.97- 9.85), and 2.95 (95 % CI: 1.95- 4.47) at four CTC positive cut points (≥ 1, ≥ 2, ≥ 3, and ≥ 5 CTCs/7.5 ml). Two studies applying the AdnaTest also documented increased death (RR: 1.38, 95 % CI: 0.42- 4.49) and relapse rates (RR: 2.84, 95 % CI: 1.35- 5.98).

CONCLUSION: Results of this meta-analysis allude CTCs as potent prognostic marker in primary breast cancers prior to any systemic therapy especially when it is studied via CellSearch ® administration, considering that the more the CTCs, the greater the death and relapse rates.