Prognostic Significance of Metabolic Response by Positron Emission Tomography After Neoadjuvant Chemotherapy for Resectable Malignant Pleural Mesothelioma

Background: To select optimal candidates for extrapleural pneumonectomy (EPP), we retrospectively evaluated the usefulness of metabolic response by fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) after neoadjuvant chemotherapy to predict prognosis for patients with resectable malignant pleural mesothelioma (MPM) who underwent EPP in a multicenter study.

Patients And Methods: We carried out high-resolution CT (HRCT) and FDG-PET/CT before and after neoadjuvant platinum-based chemotherapy on 50 patients with clinical T1-3 N0-2 M0 MPM who underwent EPP ± postoperative hemithoracic radiotherapy. A decrease of ≥30% in the tumor maximum standardized uptake value (SUVmax) was defined as a metabolic responder. The radiologic response using the modified RECIST or metabolic response and surgical results were analyzed.

Results: The median overall survival (OS) from diagnosis was 20.5 months. Metabolic responders significantly correlated to OS with median OS for metabolic responders not reached versus 18.7 months for non-responders. No correlation was observed between OS and radiologic response with median OS for radiologic responders and non-responders. Based on the multivariate Cox analyses, decreased SUVmax and epithelioid subtype were significantly independent factors for OS.

Conclusions: The metabolic response after neoadjuvant chemotherapy is an independent prognostic factor for patients with resectable MPM. Patients with metabolic responder or epithelioid subtype may be good candidates for EPP.