Objective PIWI-interacting RNA (piRNA) has emerged as a promising tool for cancer diagnosis. The aim of this meta-analysis was to summarize the existing literature and systematically assess the diagnostic performance of piRNAs in cancer, as well as identify potential sources of inter-study heterogeneity to provide information for clinical practice. MethodsThe PubMed, Web of Science, Embase, Cochrane library, CNKI, WanFang, VIP and CBM databases were electronically searched to collect diagnostic trials of piRNAs in cancer from inception to April 2023. The methodological quality of the included studies was assessed using the QUADAS-2 tool, and statistical analysis was conducted using Stata 17.0 software. ResultsA total of 17 papers (46 studies) involving 4 956 cancer patients and 3 759 controls were included. The range of sensitivity was 21%-100% and the range of specificity was 50%-100%. Meta-analysis showed that the combined sensitivity of piRNA for the diagnosis of cancer was 0.74 (95%CI 0.68 to 0.79), the specificity was 0.79 (95%CI 0.75 to 0.82), the PLR was 3.49 (95%CI 3.01 to 4.05), the NLR was 0.33 (95%CI 0.27 to 0.40), DOR of 11 (95%CI 8 to 14), and AUC of 0.83 (95%CI 0.80 to 0.86), indicating that piRNA had high accuracy for cancer diagnosis. Conclusion piRNA shows promise as a reliable biomarker for cancer diagnosis, with good sensitivity and specificity. However, the lack of standardization and result reproducibility remain significant challenges in the clinical application of piRNA-based diagnostics.