Prognostic Role of Circulating Tumor Cells in Resectable Colorectal Liver Metastases

Abstract

Background: A systematic review and meta-analysis was performed to assess the prognostic role of preoperative, intraoperative, and postoperative circulating tumor cells (CTC) in resectable colorectal liver metastases (CRLM). Methods: The following databases were searched in May 2021: Medline, Embase, Biosis, Cochrane, Web of Science, and clinicaltrials.gov. Resectable CRLM where CTC was detected using CellSearch® (FDA approved) or RT-PCR was included. A random-effects model was used for pooled and subgroup analyses of Disease-Free Survival (DFS) and Overall Survival (OS). Surgical resections performed for palliative purposes were excluded. Randomized and non-randomized clinical trial, and cohort studies were included. Hazard ratio (HR) along with confidence interval (CI) were extracted or calculated using the Tierney method. Study bias was assessed using the Newcastle-Ottawa (NOS) scale. Results: 10 studies (801 patients) were identified for qualitative analysis (Table 1). 9 studies (781 patients) were included in the pooled analysis, out of which 6 studies detected CTC using CellSearch®. Two studies were high quality based on NOS. There was no statistical difference in DFS in patients with preoperative CTC (HR 1.97; 95% CI 0.85 – 4.57), intraoperative CTC (HR 3; 95% CI 0.98 – 9.21), and postoperative CTC (HR 1.93, 95% CI 0.82 – 4.57) detected in peripheral blood with CellSearch®. The OS was worse in patients with preoperative CTC (HR 2.36, 95% CI 1.15 – 4.84) (Figure 1) but similar in patients with intraoperative CTC (HR 2.33, 95%, 0.79 – 6.83). Conclusion: Preoperative CTC detected in peripheral blood using CellSearch® may predict OS in patients undergoing liver resection for CRLM.