8518 Background: Although pleurectomy/decortication (P/D) has become a preferred surgical technique for malignant pleural mesothelioma (MPM), only a few prospective, multi-center clinical trials have been conducted. Here we present final results of a nationwide, prospective, multi-institutional study to evaluate the feasibility of induction chemotherapy followed by P/D. Methods: Eligibility criteria: a histologically confirmed diagnosis of MPM; clinical T1–3, N0–2, M0 disease; no prior treatment for the disease; age between 20 and 75 years; ECOG performance status of 0 or 1; and written informed consent. Treatment methods: Induction chemotherapy of pemetrexed 500 mg/m2 plus cisplatin 75 mg/m2 for 3 cycles, followed by P/D. Intraoperative conversion from P/D to extrapleural pneumonectomy (EPP) was permitted. Pulmonary function tests were performed at 3, 6, 12, 24, and 36 months after surgery. Primary endpoint was macroscopic complete resection (MCR) rate regardless of the surgical technique. Results: Of 24 patients enrolled, 20 patients were eligible: median age 66 (48–74); M/F: 17/3, Clinical stage I/II/III: 8/9/3; Histology epi/sar/bi: 19/1/0. Two discontinued protocol before surgery due to deteriorated FEV1 or adverse effect (AE) of chemotherapy, and the remaining 18 patients completed surgery with MCR: P/D in 15 patients and EPP in 3. The trial met the primary endpoint with MCR rate of 90% (18/20). There was no treatment-related 30- and 90-day mortality. There were two cases of chemotherapy-related grade 4 AEs, but no surgery-related grade 4 AE occurred. The overall survival rates at 1 and 2 years and median survival time (MST) after registration were 95.0% (95% CI, 69.5 to 99.3), 70.0% (45.1 to 85.3), and 41.4 months (19.7 to NA), respectively. The progression-free survival rates at 1 and 2 years and MST after registration were 84.7% (60.0 to 94.8), 42.4% (20.5 to 62.7), and 22.9 months (12.7 to 28.4), respectively. Recurrence occurred in 17 patients, and initial relapse sites were local in 17 (100%) and distal in 6 (35.3%). The best values of FVC and FEV1 during postoperative period were 78.0% and 82.5% of preoperative values, respectively. Conclusions: Induction chemotherapy plus P/D yielded a MST over 40 months with acceptable risks. Postoperative pulmonary function was approximately 80% of preoperative value. Clinical trial information: UMIN000009092.