Tenosynovial giant cell tumor (TGCT)/pigmented villonodular synovitis (PVNS): Outcome of 313 patients before the era of kinase inhibitors

Background: Tenosynovial giant cell tumor (TGCT) is a rare, usually benign neoplasm of synovium and tendon sheath. TGCT is classified as localized or diffuse according to the extent of synovial involvement. Surgery is the primary treatment, but the recurrence rate is high, with possible multiple recurrences, joint function deterioration and decline in quality of life. Recent data suggest a role for TKIs in advanced disease. In order to identify prognostic factors for recurrence, a retrospective pooled analysis was carried out in three institutions (Istituto Ortopedico Rizzoli, Bologna, Italy; Istituto Nazionale Tumori, Milano, Italy; Memorial Sloan Kettering Cancer Center, New York, USA). Methods: Clinical charts and pathology reports of patients (pts) treated in the period 1998-2008 were examined. Results: The study included 313 pts, 177 F and 136 M; median age: 36 years (range: 11-89 years). Most (64%) pts had tumors in the knee (15% ankle, 11% hip, 10% other). Tumor size was: 5 cm in 32%. A diffuse pattern was reported in 69% of pts. The resection status was available in 289 pts: 51% had R0 surgery, 28% R1 and 21% R2. No metastases were documented. Local recurrence was reported in 76 pts (median time to recurrence: 15.7 months). With a median follow-up of 4.2 years, 5-year local recurrence-free survival (LRFS) was 66% (95% CI: 59 - 73). Size (5 cm 62%, p=0.04), gender (F 73% vs. M 56%, p=0.02), type (localized 78% vs. diffuse 61%, p=0.02), and resection status (R0 76% vs. R1 55%, vs. R2 57%, p=0.002) influenced 5-year LRFS, whereas age, tumor location and bone involvement did not. The 5-year 2nd LRFS was 43% (95% CI: 28 - 59). Multiple (2 to 5) local recurrences were observed in 39% of relapsed patients. Conclusions: The study confirms TGCT propensity to multiple local recurrences. Diffuse type, suboptimal surgery, male gender and larger tumors increase the recurrence risk. In order to improve the probability of local control, studies addressing the role of TKIs could be considered in subsets of patients