Testicular cancer in Latvia: incidence trends and prognostic outcomes across a 23-year study

Background: The aim of this study was to analyze trends in testicular cancer incidence, mortality, and survival in Latvia from 1994 to 2017. Materials and methods: This retrospective cohort study analyzed testicular cancer patients diagnosed in Latvia between 1994 and 2017. The population-based cancer registry recorded nearly all cases. Patients were categorized by age, tumor histology (seminoma, non-seminoma, unspecified), and disease stage according to the TNM classification system. The Joinpoint regression model was used to analyze trends in incidence, mortality. Kaplan-Meier analysis was performed to calculate 5- and 10-year cancer-specific and overall survival probabilities. Results: During the study period, the age-standardized incidence rate of testicular cancer increased from 2.25 to 3.57 per 100,000, with an annual percentage change (APC) of 2.37% (95% CI: 0.78, 3.9). The incidence of both seminoma and non-seminoma increased significantly. The APC for seminoma was 3.186% (95% CI: 0.429, 5.991), while for non-seminoma, it was 4.104% (95% CI: 0.486, 52.597). The overall and cancer-specific 5-year survival probabilities in Latvia were 70.6% (95% CI: 67, 74) and 76.4% (95% CI: 73.4, 79.6), respectively. The overall and cancer-specific 10-year survival probabilities were 66% (95% CI: 62, 69) and 74.0% (95% CI: 70.8, 77.4), respectively. The 5-year overall survival rate increased by 19.8 percentage points, from 59.1% in 1994-1999 to 80.9% in 2010-2017. The observed 5-year cancer-specific survival increased by 27.4 percentage points over the same period. The mortality rate did not change significantly, with an APC of 1.32% (95% CI: -1.52 to 4.2) during this period. Conclusions: A moderate increase in testicular cancer incidence was observed in Latvia over 23 years, while the mortality rate remained stable. The 5-year relative survival improved over different time periods; yet outcomes could be further enhanced if a multidisciplinary approach to diagnostics and management had been implemented in Latvia, as in other countries.