Diagnostic and prognostic value of circulating tumor cells in renal cell cancer: A systematic review and meta-analysis.

Renal cell carcinoma (RCC) is a type of tumor with high morbidity and recurrence rates. The application of circulating tumor cells (CTCs) in RCC remains controversial. Hence, we performed a meta-analysis to elucidate the diagnostic and prognostic value of CTCs in RCC. To obtain a precise conclusion, a systematic search was conducted in Pubmed, Cochrane Database, Embase and Web of Science up to Dec 01, 2022. We also further identified the references in relevant studies. The diagnostic accuracy variables (sensitivity, specificity) and odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to access precise of CTCs and relationship between CTCs and disease stages, respectively. Heterogeneity test, sensitivity analysis, meta-regression and publishing bias were also applied. A total of 12 studies involving 767 patients were considered to be included in the final meta-analysis. The results revealed that the overall sensitivity, specificity of CTC detection in RCC were 45% (95%CI, 32-60%) and 99% (95%CI, 97-100%), respectively. In subgroup analysis, diagnostic sensitivity of CTCs in clear cell renal cell carcinoma (ccRCC) (69%, 95%CI; 50-88%) was significantly higher than other RCC subtypes (34%, 95%CI; 21-48%) (p<0.05). Meanwhile, advanced diseases (stage III-IV) were more likely to find CTCs than localized diseases (stage I-II) (OR, 2.29; 95%CI, 1.37-3.83; p = 0.002). This systematic review and meta-analysis demonstrated that CTC detection could be considered as a promising auxiliary diagnostic and staging method for RCC, especially ccRCC subtype. Meanwhile, the presence of cytokeratin-positive CTCs is highly likely associated with increased risk of poor prognosis in RCC.