CDKN2A/B deletions are strongly associated with meningioma progression: a meta-analysis of individual patient data.Homozygous CDKN2A/B deletion has been associated with an increased risk of recurrence in meningiomas.  However, the evidence is confined to a limited number of studies, and the importance of heterozygous CDKN2A/B deletions remains insufficiently investigated.  Hence, the present meta-analysis reconstructs individual patient data (IPD) and reconstructs the probabilities of progression-free survival (PFS) stratified by CDKN2A/B status.  IPD of PFS rates were extracted from published Kaplan-Meier plots using the R package IPDfromKM in R studio (RStudio, Boston, MA, USA).  Reconstructed Kaplan-Meier Plots of the pooled IPD data were created.  One-stage and two-stage meta-analyses were performed.  Hazard ratios (HR) were used as effective measures.  Of 181 records screened, four articles with 2521 participants were included.  The prevalence of homozygous CDKN2A/B deletions in the included studies was 0.049 (95% CI 0.040-0.057), with higher tumor grades associated with a significantly greater proportion of CDKN2A/B deletions.  The reconstructed PFS curves for the pooled cohort showed that the median PFS time of patients with a CDKN2A/B wild-type status, heterozygous or homozygous CDKN2A/B deletion was 180.0 (95% CI 145.7-214.3), 26.1 (95% CI 23.3-29.0), and 11.00 (95% CI 8.6-13.3) months, respectively (p < 0.0001).  Both hetero- or homozygous CDKN2A/B deletions were significantly associated with shortened time to meningioma progression.  One-stage meta-analysis showed that hetero- (HR: 5.5, 95% CI 4.0-7.6, p < 0.00001) and homozygous CDKN2A/B deletions (HR: 8.4, 95% CI 6.4-11.0, p < 0.00001) are significantly associated with shortened time to meningioma progression.  Multivariable Cox regression analysis of progression in a subgroup with available covariates (age, sex, WHO grade, and TERT status) and also two-stage meta-analysis confirmed and validated the results of the one-stage analysis that both heterozygous and homozygous CDKN2A/B deletions are of prognostic importance.  Further large-scale studies of WHO grade 2 and 3 meningiomas are needed to validate the importance of heterozygous CDKN2A/B deletions with consideration of established factors.
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IPD of PFS rates were extracted from published Kaplan-Meier plots using the R package IPDfromKM in R studio (RStudio, Boston, MA, USA). 
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