The South West Area Mesothelioma and Pemetrexed trial: a multicentre prospective observational study evaluating novel markers of chemotherapy response and prognostication.

BACKGROUND

Robust markers that predict prognosis and detect early treatment response in malignant pleural mesothelioma (MPM) would enhance patient care.

METHODS

Consecutive patients with MPM who were considered fit for first-line chemotherapy were prospectively recruited. Patients of similar performance status opting for best supportive care were included as a comparator group. Baseline and interval CT, PET-CT and serum markers (mesothelin, fibulin-3 and neutrophil-lymphocyte ratio (NLR)) were obtained, and patients followed up for a minimum 12 months.

FINDINGS: Seventy-three patients were recruited (58 chemotherapy/15 comparator arm). Baseline TGV (total glycolytic volume on PET-CT) was an independent predictor of worse overall survival (OS) (P=0.001). Change in interval TGV(baseline/after two cycles of chemotherapy) did not predict OS or chemotherapy response on CT. Baseline NLR<4 was an independent predictor of better OS (median survival 453 (IQR 272-576) days vs NLR⩾4, 257 (IQR 147-490), P=0.002). Although baseline serum mesothelin did not predict OS, a falling level at 8 weeks significantly predicted longer time to progression (TTP) (P<0.001).

INTERPRETATION: Neutrophil-lymphocyte ratio and baseline TGV predict prognosis in malignant pleural mesothelioma (MPM), but PET-CT is unhelpful in monitoring chemotherapy response. Serum mesothelin is a useful early treatment response marker when measured serially during chemotherapy and may have a role in evaluating patients' treatment response.