Circulating tumor cells and prognosis of patients with resectable colorectal liver metastases or widespread metastatic colorectal cancer: a meta-analysis

Abstract

Background: We performed a systematic review and meta-analysis to investigate the prognostic value of tumor cells in blood (circulating tumor cells [CTCs]) or bone marrow (BM) (disseminated tumor cells) of patients with resectable colorectal liver metastases or widespread metastatic colorectal cancer (CRC).

Materials and methods: The following databases were searched in May 2011: MEDLINE, EMBASE, Science Citation Index, BIOSIS, Cochrane Library. Studies that investigated the association between tumor cells in blood or BM and long-term outcome in patients with metastatic CRC were included. We extracted hazard ratios (HRs) and confidence intervals (CIs) from the included studies and performed random-effects meta-analyses for survival outcomes.

Results: The literature search yielded 16 studies representing 1,491 patients. The results of 12 studies representing 1,329 patients were suitable for pooled analysis. The overall survival (HR, 2.47; 95 % CI 1.74-3.51) and progression-free survival (PFS) (HR, 2.07; 95 % CI 1.44-2.98) were worse in patients with CTCs. The subgroup of studies with more than 35 % CTC-positive patients was the only subgroup with a statistically significant worse PFS. All eight studies that performed multivariable analysis identified the detection of CTCs as an independent prognostic factor for survival.

Conclusion: The detection of CTCs in peripheral blood of patients with resectable colorectal liver metastases or widespread metastatic CRC is associated with disease progression and poor survival.