Prognostic value of circulating tumor cells and disseminated tumor cells in patients with ovarian cancer: a systematic review and meta-analysis

Recent studies have shown diagnostic and prognostic values of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) in various cancers, including ovarian cancer. We aimed to evaluate the association of CTCs and/or DTCs with the clinical outcomes of ovarian cancer. Clinical studies of CTCs/DTCs of ovarian cancer were included for systematic review and meta-analysis. A total of 236 studies were screened but only 16 qualified studies with 1623 subjects were included. Odds ratio (OR) showed CTCs/DTCs were not significantly associated with serous carcinoma (OR = 0.71 [0.49, 1.05]), lymph node metastasis (OR 1.14 [0.67, 1.93]), and residual disease (OR 1.45 [0.90, 2.34]); but significantly associated with advanced tumor staging (OR = 1.90 [1.02, 3.56]). The overall pooled hazard ratio (HR) of CTCs/DTCs on OS and PFS/DFS was 1.94 [1.56– 2.40] and 1.99 [1.59–2.50], respectively. Subgroup analyses revealed that CTCs were significantly associated OS (HR 1.97 [1.50-2.58]) and PFS/DFS (HR 2.52 [1.83-3.48]), while DTCs was significantly associated OS (HR 1.89 [1.33, 2.68]) and PFS/DFS (HR 1.60 [1.17, 2.19]). Meta-analysis showed strong relationship of CTCs/DTCs with advanced staging, treatment response and poor prognosis in patients with ovarian cancer.