Microvessel density as a prognostic factor in renal cell carcinoma: A systematic review and meta-analysis with individual patient data reconstructed from previous Kaplan‒Meier curves

BACKGROUND: The prognostic value of microvessel density (MVD) in renal cell carcinoma (RCC) is controversial. This study aimed to clarify its significance by performing a meta-analysis with individual patient data (IPD) reconstructed from published Kaplan‒Meier curves. METHODS: We systematically searched PubMed, EMBASE, Web of Science, and CNKI. For studies providing only Kaplan‒Meier curves, IPD were reconstructed using the IPDfromKM platform. Hazard ratios (HRs) were pooled using a random-effects model for overall (OS), progression-free (PFS), and cancer-specific survival (CSS), with extensive subgroup analyses. RESULTS: From 46 studies, higher MVD was significantly associated with improved PFS (HR = 0.69, 95% CI: 0.49-0.98), but not OS (HR = 0.83) or CSS (HR = 0.96). Subgroup analyses revealed that MVD assessed by CD31 was a strong, favorable prognostic marker for both OS (HR = 0.75, 95% CI: 0.58-0.96) and PFS (HR = 0.62, 95% CI: 0.48-0.80). Furthermore, high MVD was associated with better OS in European (HR = 0.55) and North American (HR = 0.67) populations. Studies with reconstructed HRs also showed a significant link to better PFS (HR = 0.59). CONCLUSION: The prognostic value of MVD in RCC is highly context-dependent. MVD assessed by CD31 is a significant, favorable prognostic indicator for OS and PFS, particularly in Western populations. Our findings, enabled by an innovative IPD reconstruction workflow, underscore the need for original IPDs and CD31 based standardized methodologies to identify specific clinical contexts where MVD assessment is prognostically valuable.