Prediction modelling using routine clinical parameters to stratify survival in Malignant Pleural Mesothelioma patients undergoing cytoreductive surgery.

Abstract

BACKGROUND: Malignant Pleural Mesothelioma (MPM) is an uncommon cancer with a poor prognosis and heterogeneous survival. Surgery for MPM is offered in some specialist centres to highly selected patients. A previously described classification and regression tree (CART) model stratified survival in unselected MPM patients using routinely collected clinical data. This study aimed to examine the performance of this CART model on a highly selected surgical population. METHODS: Data were collected from subjects undergoing cytoreductive surgery for MPM from specialist centres in Hyõgo, Japan and Sydney, Australia between 1991 and 2016. The CART model was applied using the combination of clinical variables to stratify subjects into risk groups (1-4); survival characteristics were then compared. RESULTS: 289 cases were included (205 from Australia, 84 from Japan). Overall median survival was 34.6 (IQR 17.5-56.1) months; median age 63.0 (IQR 57.0-67.8) years, 240/289 (83.0%) were male. There were no clinically meaningful differences between the two cohorts. Survival across the four risk groups was significantly different (p<0.0001); the model stratified survival well with a Harrell's c-statistic of 0.62 (96% CI 0.57-0.66) at 36 months. The group with the longest survival (median 82.5 months) had: no weight loss, Hb >153g/L and serum albumin >43g/L at time of referral to the surgical centre. CONCLUSION: Using routinely available clinical variables the CART model was able to stratify surgical patients into risk groups with statistically different survival characteristics with fair to good performance. Presence of weight loss, anaemia and low albumin should confer caution when considering surgical therapy for MPM.