Background
Clear cell sarcoma (CCS) is a rare soft tissue cancer that predominantly affects young to middle-aged adults. Current literature lacks recent accurate estimates of patient outcomes due to the disease’s low incidence and the small sample sizes in studies, particularly at a national registry level. This study aims to examine the incidence and survival of patients with CCS.
Methods
Patients from the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with CCS between 2000-2020 were selected. Additional variables were collected including age, sex, race, stage, presence of metastases, tumor size, treatment status for surgery, radiation, and chemotherapy, time to treatment, median household income, and population size. Descriptive statistics, population-based incidence, log-rank tests with Kaplan-Meier curves, and Cox regression analyses were performed.
Results
A total of 287 patients were included. The population-adjusted incidence ranged from 0.012/100000 in 2004 to 0.027/100000 in 2010. The total percent change over the study period was 16.751% and the annual percent change, which did not change significantly over the study period, was 0.561%. The survival rate was 78.4% at one year, 62.0% at three years, and 57.1% at five years. Log-rank results showed Black patients survived shorter than White and Hispanic patients. Further, greater staging and tumor size >4.0cm were associated with shorter survival (p’s< 0.001). After controlling for covariates, Cox regression results showed Black patients were associated with shorter survival compared to White patients (p=0.038, hazard ratio=2.590). No other covariates were significantly associated with survival.
Conclusions
The findings showed CCS incidence is unchanged in recent years and prognosis is poor. Additionally, Black patients were associated with shorter survival duration compared to White patients. Contrary to prior findings on CCS, staging and tumor size were only significantly associated during univariate analyses, but not on Cox regression. The study was limited by a small sample size and variables found in the SEER database. Nonetheless, future research will benefit from assessing how race is an independent risk factor for CCS survival and how the prognosis of CCS patients can be improved.
