Clinicopathological characteristics and survival outcomes for testicular choriocarcinoma: a population-based study

Due to the scarcity of cases of testicular choriocarcinoma (CC), its clinicopathological characteristics and prognosis have not been well summarized. Consequently, we conducted this population-based case-control study to characterize the features of testicular CC.

The SEER database was used to extract qualified data. Dichotomous variables were compared by Pearson's Chi-squared or Fisher exact test. Survival variables were compared by Kaplan-Meier analyses and log-rank tests. The univariable and multivariable Cox regression analyses were applied to figure out risk factors for overall survival (OS) and cancer-specific survival (CSS). Propensity score matching (PSM) was used to control confounding factors in the study.

In total, 788 patients with CC and 19,571 patients with seminoma were identified. Significant differences were found between two groups in terms of age (≤30 years: 65.4% vs. 26.5%; >30 years: 34.6% vs. 73.5%; P<0.001), marital status (28.8% vs. 52.1%; P<0.001), laterality (proportion of bilateral tumors: 4.1% vs. 1.0%, P<0.001), tumors size (≤4 cm: 40.2% vs. 49.3%; >4 cm: 45.8% vs. 43.0%; P<0.001), SEER stage (localized: 43.9% vs. 79.1%; regional: 14.6% vs. 15.4%; distant: 41.0% vs. 4.7%; P<0.001), surgery (92.4% vs. 98.2%; P<0.001) and chemotherapy (65.4% vs. 19.8%; P<0.001). However, no differences were found between two groups after Propensity Score Matching (PSM). Furthermore, CC had worse outcomes than seminoma in terms of 5-year rate of OS (85.5% vs. 97.3%) and 5-year rate of CSS (86.8% vs. 98.6%). In univariable Cox hazard model, age, laterality, SEER stage (distant), surgery, chemotherapy and pathological type were independent prognostic factors for OS and CSS. However, in multivariable Cox hazard model, only age, SEER stage(distant) and surgery remained as the independent prognostic factor for OS and CSS.

Choriocarcinoma is exceedingly rare disease with metastases at initial diagnose and has poor survival even after treatment. Old age and advanced tumor stage indicate a poor prognosis, while surgery therapy can improve prognosis. Nevertheless, longer-term studies with larger population of patients are needed to verify their biological behavior and therapeutic efficacy.