P1-141: The role of FDG-PET/TC in the surgical approach of malignant pleural mesothelioma

Abstract

Approximately 20-30% of patients undergoing explorative thoracotomy because of the inaccurate imaging used for staging in malignant pleural mesothelioma (MPM). FDG-PET/TC scan could help in preoperative staging, in operative evaluation and in postoperative follow-up in MPM. Data from patients with pathologically proven, previously untreated, MPM was obtained from a prospective database. All patients underwent FDG-PET/TC scan. Patients were clinically staged using IMIG staging system. Operative selection criteria were: ps 0-1, cStage I-II, epithelial histology, predictive postoperative FEV1>1.0 L and resectable lung perfusion <50%, PaO2>65 mmHg, PaCO2>45 mmHg, ejection fraction >40%. Videothoracoscopy for diagnosis and for pleurodesis was made in all the cases. Fifty-five potentially EPP submitted patients (range age of 31-70 years) were observed between 1999 and 2006. Median PET SUV prior surgery in the primary tumor was 6.8 (range 4-16). The same surgeon team operated 33 patients with MPM (21 male – 12 female), with one only thoracotomic approach in 30 cases, 20 right-sided lesions and 13 left-sided. Twenty-nine patients underwent EPP, 3 exploratory thoracotomies without resection for chest wall or inferior vena cava invasion, and 1 laparoscopy for peritoneal metastases. All T4 or M1 cases were detected by FDG-PET/TC preoperative scan. Pericardial (n=26) and diaphragmatic (n=29) defects were repaired by PTFE. Twenty-six patients had epithelioid subtype, 3 sarcomatous and 4 biphasics. Sixteen tumors were pStage I-II, 12 pStage III and 4 pStage IV. Of the 55 patients who had both FDG-PET/TC and surgical procedure only 4 had unresectable tumors. FDG-PET/TC correctly identified 1 unresectable tumor for proven peritoneal metastases. The follow-up study reported a sensibility of 95% with a diagnostic accuracy of 92% regarding the local recurrences or distant metastases. The analysis correlation in patients with high and low SUV and epithelioid and non-epithelioid histotype showed a better prognosis in both low SUV and epithelioid tumor. FDG-PET/TC appears to give a good support in staging and prognosis in MPM. Furthermore, a systematic use of PET scan could be prevent the recurrence of MPM in follow-up period in EPP submitted patients.