Risk factor analysis for the recurrence of resected solitary fibrous tumours of the pleura: A 33-year experience and proposal for a scoring system

Abstract

Objectives: Surveillance after resection of solitary fibrous tumours of the pleura (SFTP) remains undefined. This study reviews our experience with surgical treatment of SFTP to determine the specific risk factors to predict recurrence. METHODS: A retrospective review of 59 patients surgically treated for SFTP during the years 1977-2010 was conducted. Clinico-pathological factors for recurrence were analysed by Kaplan-Meier and Cox proportional hazard methods. Results: The mean age was 57 ± 14 years. There were 32 (54%) men. Among 32 (54%) symptomatic patients, chest pain (22%), cough (19%) and dyspnoea (17%) were most frequent. The mean tumour size was 7.3 ± 6.7 cm, and 14 patients had SFTPs larger than 10 cm. An SFTP was pedunculated in 38 (67%) cases and had a visceral origin in 40 (68%). Paraneoplastic syndromes were observed in 3 (5%) patients. On histopathologic analysis, 4 (7%) presented ≥4 mitosis/10 high-power fields (HPFs), 8 (15%) atypia, 14 (24%) hypercellularity and 6 (10%) necrosis. After a mean follow-up of 8.8 ± 7.0 years, we observed 8 (14%) recurrences; median time to recurrence was 6 years (range 2-16 years). Two (3%) patients received adjuvant therapy. We constructed a predictive score for recurrence by assigning one point to each of the six variables: parietal (vs visceral) pleural origin, sessile (vs pedunculated) morphology, size >10 cm (vs <10 cm), the presence of hypercellularity, necrosis and mitotic activity ≥4/HPF (vs <4). A score of ≥3 best predicted recurrence (sensitivity: 100%, specificity: 92%, area under receiver operating characteristic curve = 0.966, P < 0.0001). With a score of ≥3, recurrence-free survival was 80%, 69, 23 and 23% at 3, 5, 10 and 15 years, whereas a score of <3 was 100% up to 15 years. Our scoring system was superior in predicting malignant behaviour and recurrence compared with England's criteria or de Perrot staging. CONCLUSIONS: The proposed scoring system is simple, easily obtained from existing pathological description and reliably predicts recurrence in this patient population harbouring SFTP. The SFTP score may stratify patient risk and guide postoperative surveillance. We recommend validation in additional clinical series. ©The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.