Validation of a scoring system to predict recurrence of resected solitary fibrous tumors of the pleura.

BACKGROUND Solitary fibrous tumors of the pleura (SFTPs) are infrequent neoplasms with no standardized criteria to predict risk of recurrence after curative surgery. The aim of the present study is to validate a recently proposed recurrence score in a large European cohort of patients with SFTP. METHODS Validation of a previously published scoring system was assessed in a population of 113 patients who underwent complete resection of SFTPs. Patients were scored according to the pleural origin, morphology, size, hypercellularity, presence of necrosis or hemorrhage, and number of mitoses in their SFTPs. Receiver operating characteristic curves were plotted for the score. Time to recurrence analysis was performed using the Kaplan-Meier and Cox proportional hazards methods. RESULTS After a mean follow-up of 13.2 ± 7.3 years, there were nine recurrences (8.0%). Score performance to predict recurrence was as follows: sensitivity = 78%, specificity = 74%, positive likelihood ratio = 3.0, and negative likelihood ratio = 0.3. A cutoff of 3 points was used to classify 79 patients (69.9%) at low risk and 34 patients (30.1%) at high risk for recurrence. A high-risk classification was significantly associated with more recurrences during follow-up (P = .004), worse overall survival (P = .0008), more extensive lung resections (P = .001), and the use of adjuvant therapies (P = .009). The present score outperformed England's criteria (P = .049) and de Perrot classification (P < .001) when predicting SFTP recurrence. CONCLUSIONS The proposed scoring system, which combines common clinical and histologic features of resected SFTPs, remains predictive of recurrence in a separate patient population. The simple score may guide the postoperative surveillance of this uncommon tumor.