Article Text
Abstract
Introduction Malignant Pleural Mesothelioma (MPM) is presaged by Benign Asbestos Pleural Effusion (BAPE) in some patients. In a future study (called Meso-ORIGINS) we will collect longitudinal BAPE-MPM tissue pairs in patients who develop MPM following BAPE and use this material in the PREDICT-Meso CRUK Accelerator programme. PREDICT-Meso will define the key biological events that drive or permit evolution of MPM, generate new pre-clinical models and define new therapeutic targets. At initial planning, the only data reporting BAPE-MPM evolution rate were derived from a single-centre study (n=44 BAPE patients) with wide confidence intervals around the estimate reported (12% (95%CI 5%–24%, Davies et al, 2010). Here we report the preliminary findings of a retrospective analysis performed as part of the multi-centre Meso-ORIGINS feasibility study. The primary objective was to define the BAPE-MPM evolution rate more precisely, to generate a reliable sample size estimate for Meso-ORIGINS.
Methods Patients were identified from databases in Glasgow, Oxford, Manchester & Bristol. Eligibility required 2-years complete follow-up data following a diagnosis of BAPE, which was defined as asbestos exposure (history or imaging) plus compatible histology (benign fibrinous pleurisy, non-specific pleuritis, atypical mesothelial proliferation). Comprehensive clinical data were recorded including demographics, radiological findings, blood and pleural fluid results. These will be used to build a logistic regression model for higher MPM evolution risk, to refine the eligibility criteria of the Meso-ORIGINS study. BAPE-MPM evolution was defined as any diagnosis of MPM within 2-years of the diagnosis of BAPE.
Results Data collection is complete in 3 of 4 centres. At the time of writing, data collection is complete in 207 eligible patients with BAPE. Mean (SD) age is 71.8 (9.7) years. 97% of cases are male. On baseline imaging, 64% had pleural plaques and 28% cases had features suggestive of pleural malignancy. The BAPE-MPM evolution rate was 30/207 or 14.5% (95%CI 9.9–19.9%).
Conclusions The final results of this study will allow optimal design of the Meso-ORIGINS study, which is a major component of the PREDICT-Meso CRUK Accelerator programme. If the BAPE-MPM progression rate is similar to the provisional rate reported here, this would translate into a feasible sample size.