Clinical outcomes of molecularly confirmed clear cell sarcoma from a single institution and in comparison with data from the surveillance, epidemiology, and end results registry

BACKGROUND: The authors compared disease-specific survival (DSS) in stage-specific subgroups of patients with clear cell sarcoma, including those with lymph node metastases (N1M0) and those with distant metastases (N0M1). METHODS: Clinical data regarding soft tissue sarcoma patients were obtained from The University of Texas M. D. Anderson Cancer Center (MDACC) (1980-2007) and the Surveillance, Epidemiology, and End Results (SEER) registry (1988-2004). When possible, clear cell sarcoma diagnoses were confirmed using fluorescence in situ hybridization or reverse-transcription polymerase chain reaction. Kaplan-Meier estimates were used to calculate DSS, and Cox multivariate analysis was performed to identify prognostic factors. RESULTS: Fifty-two patients at MDACC and 130 SEER patients were diagnosed with clear cell sarcoma. Five-year DSS for the MDACC and SEER cohorts were 67% and 62%, respectively. Patients with N1M0 and N0M1 disease demonstrated significant differences in 5-year DSS: 74% versus 14% at MDACC (P = .014) and 52% versus 0% in SEER (P = .014). After adjustment, the hazards ratio (HR) for dying was 2.79 for N1M0 disease (95% confidence interval [95% CI], 1.32-5.91) and 11.37 (95% CI, 5.19-24.91) for N0M1 disease compared with stage II disease (P < .001). Non-Caucasian ethnicity (HR, 3.99; 95% CI, 2.27-6.99 [P < .001]) and truncal tumor site (HR, 2.41; 95% CI, 1.15-5.05 [P = .02]) were also found to be predictors of decreased DSS. CONCLUSIONS: The findings of the current study suggest that patients with N1M0 clear cell sarcoma have 5-year DSS that is more similar to that of patients with stage III than stage IV soft tissue sarcoma.