Disease and Patient Characteristics related to Survival in a large population-based cohort of patients with Malignant Pleural Mesothelioma (MPM) (#51)
Although the prognosis of MPM remains poor, a small proportion of patients demonstrate long-term survival. We assess what factors independent of treatment predict for an improved prognosis.
We reviewed patients registered with the NSW Dust Diseases Board (2002-2009) evaluating a-priori prognostic factors including age, gender, histological subtype, stage and Neutrophil-Lymphocyte ratio (NLR) using Kaplan-Meier and Cox-regression analysis, and by treatment interventions, smoking and asbestos exposure. Exploratory subgroup analyses compared these factors in long-term survivors(>20 months) versus the remainder of the study population.
We identified 913 patients: 90% male; median age 71.9 years; histological subtype (epithelioid 54%; biphasic 11%; sarcomatoid 16.3%; unknown 19%); stage (Tx-I-II 49%; III-IV 51%). Treatment: chemotherapy 51%, extrapleural pneumonectomy (EPP) 6% (with 67% receiving chemotherapy). Median age of first occupational asbestos exposure was 18 years, cumulative exposure 24 years, latency from exposure to diagnosis 50 years.
Median overall survival (OS) was 10.0 months; 15.0 months in chemotherapy and/or EPP patients, 5.8 months in patients receiving neither. Younger age (<70 vs. >70yrs; 13.1 vs. 8.5 months;p<0.001); female gender (12.0 vs. 9.8months;p<0.001); epithelioid subtype (11.8 vs. 7.2 months;p>0.001); and NLR <5 (12.9 vs. 7.5months;p<0.001) were associated with prolonged OS. Patients who underwent chemotherapy (13.6 vs. 7.2 months; p<0.001) and EPP (17.9 vs. 9.6 months; p<0.001) had improved survival. Smoking history and cumulative asbestos exposure did not affect survival. On multivariate analysis, age, gender, subtype, NLR, EPP and chemotherapy administration remained significant.
24% of patients survived over 20 months:14% underwent EPP, 63% received chemotherapy. Epithelioid histology (p<0.001), chemotherapy (p=0.002), EPP(p=0.01) and NLR<5(p=0.007) were independently associated with survival over 20 months.
In this large, population-based cohort, we have validated age, gender, histological subtype and NLR as significant prognostic factors. Patients undergoing EPP/chemotherapy demonstrated better survival; however 86% and 37% of long survivors respectively did not receive radical surgery or chemotherapy.