Cancer ratio plus and malignant pleural effusion: a systematic review and meta-analysis of diagnostic test accuracy study
Year: 2026
Type: review
Study designs: Systematic Review, Meta-Analysis
Abstract: Background: The current reference standards for diagnosing malignant pleural effusion (MPE) are effusion cytology and pleural biopsy, which have limitations in invasiveness and subjectivity. Effusion or serum chemistries offer minimal invasiveness, low cost, and objectivity. They are therefore usually used to support the diagnosis of MPE in patients with undiagnosed pleural effusion. Multiple studies have shown that the cancer ratio (CR) plus has diagnostic value for MPE, but findings have varied. This study aimed to ascertain the diagnostic accuracy of CR plus for MPE using meta-analysis.Methods: We searched the PubMed and Web of Science databases through May 2026 to identify diagnostic studies that used CR plus to diagnose MPE in undiagnosed pleural effusion and reported sensitivity, specificity, and sample sizes. The study design and reference standard for MPE were not restricted. We used the revised Quality Assessment of Diagnostic Accuracy Studies-Version 2 (QUADAS-2) tool for quality assessment. We used a bivariate random-effects model to pool sensitivity and specificity. A summary receiver operating characteristic (sROC) curve was constructed. We also used likelihood ratios, diagnostic odds ratio (DOR), heterogeneity (I2), and a Fagan plot to depict the diagnostic accuracy of CR plus for MPE. Deeks’ test was used to evaluate publication bias.Results: A total of seven studies (eight cohorts) comprising 1,171 participants (507 with MPEs and 601 with benign pleural effusions) were included. The area under the sROC curve of CR plus for diagnosing MPE ranged from 0.58 to 0.98 across eligible studies. The pooled sensitivity was 0.87 [95% confidence interval (CI): 0.80–0.92], and the pooled specificity was 0.78 (95% CI: 0.60–0.90). CR plus had a pooled positive likelihood ratio of 4.0 (95% CI: 1.9–8.4), a negative likelihood ratio of 0.16 (95% CI: 0.09–0.30), and a DOR of 24 (95% CI: 7–86). The area under the curve of the sROC curve was 0.90 (95% CI: 0.88–0.93). Deeks’ test revealed no significant publication bias (P=0.11). Subgroup analysis and meta-regression were not performed due to the limited number of included studies. The QUADAS-2 assessment showed that patient selection and conduct or interpretation of the index test were the main methodological weaknesses of the included studies.Conclusions: CR plus can help pulmonologists to estimate the probability of MPE. It cannot be used alone to confirm or rule out MPE. We have to interpret its diagnostic value in the clinical context.
Source: Translational Cancer Research
Institution: Inner Mongolia Medical University
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7224093943