Factors Associated With Survival in Patients With Synovial Cell Sarcoma of the Head and Neck: An Analysis of 167 Cases Using the SEER (Surveillance, Epidemiology, and End Results) Database.

IMPORTANCE: Synovial cell sarcoma of the head and neck (SCSHN) is a rare tumor associated with significant morbidity and mortality. The literature regarding these tumors is limited to case series and case reports. We used data from the population-based US Surveillance, Epidemiology, and End Results (SEER) cancer registry to determine factors affecting both overall survival and disease-specific survival of patients with SCSHN.

OBJECTIVE: To determine the clinicopathologic and therapeutic factors determining survival in patients with SCSHN.

DESIGN, SETTING, AND PARTICIPANTS: The SEER registry was reviewed for patients with primary SCSHN from January 1, 1973, to January 1, 2011.

MAIN OUTCOMES AND MEASURES: Overall survival (OS) and disease-specific survival.

RESULTS: A total of 167 cases of SCSHN were identified. The mean (SD) age at diagnosis was 37.9 (17.3) years, and 100 (59.9%) of the patients were males. The monophasic spindle cell and biphasic variants were the most common histologic subtypes. Surgical resection and radiotherapy were performed in 150 (89.8%) and 108 (64.7%) of the cases, respectively. The median OS at 2, 5, and 10 years was 77%, 66%, and 53%, respectively. Univariate Kaplan-Meier survival analysis revealed that age, race, and tumor stage and size were associated with improved survival. Histologic subtype was not associated with significant differences in survival. Radiotherapy was associated with improved disease-specific survival (hazard ratio [HR], 0.29 [95% CI, 0.12-0.68]; P = .003), but surgical management was not associated with improved survival (HR, 0.52 [95% CI, 0.19-1.46]; P = .21). Multivariate Cox regression analysis revealed that size greater than 5 cm (adjusted HR, 3.60 [95% CI, 1.43-9.08]; P = .007) and stage at presentation (adjusted HR, 3.86 [95% CI, 2.01-7.44]; P < .001) were independent determinants of OS. In separate analysis of cohorts with tumors 5 cm or less and larger than 5 cm, stage at presentation was found to be a significant indicator of the probability of survival in both cohorts (adjusted HR, 3.10 [95% CI, 1.46-6.60]; P = .003 and 5.32 [95% CI, 1.49-18.98]; P = .01, respectively); surgical resection and radiotherapy were not associated with differential survival outcomes using this model.

CONCLUSIONS AND RELEVANCE: Synovial cell sarcoma of the head and neck is rare. Independent significant determinants of survival include size (>5 cm) and stage at presentation. Histologic subtype of the tumor is not a significant indicator of the probability of survival. Surgical resection and radiotherapy were not independent determinants of survival.