Increase and Plateauing of Testicular Cancer Incidence in Austria-A Time Trend Analysis of the Past Four Decades

Background: Testicular germ cell tumors (TGCTs) are the most common malignant tumors in young men. Despite considerable geographic, ethnic, and temporal vari-ations in the incidence of TGCTs, without convincing explanation, incidence rates of TGCTs have been increasing in many countries since, at least, the mid-20th century.Objective: To investigate the incidence rates of TGCTs in Austria by analyzing data from the Austrian Cancer Registry.Design, setting, and participants: Available data between 1983 and 2018 were pro-vided by the Austrian National Cancer Registry and analyzed retrospectively. Outcome measurements and statistical analysis: Germ cell tumors derived from germ cell neoplasia in situ were classified into seminomas and nonseminomas. Age-specific incidence rates and age-standardized rates were calculated. Annual per-cent changes (APCs) and average annual percent changes in incidence rates were determined to describe trends from 1983 to 2018. All statistical analyses were per-formed using SAS version 9.4 and joinpoint. Results and limitations: The study population consists of 11 705 patients diagnosed with TGCTs. The median age at diagnosis was 37.7 yr. The standardized incidence rate of TGCTs increased significantly (p < 0.0001) from 4.1 (3.4, 4.8) per 100 000 in 1983 to 8.7 (7.9, 9.6) per 100 000 in 2018 by an average APC of 1.74 (1.20, 2.29). The joinpoint regression revealed a change point in time trend in 1995 with an APC of 4.24 (2.77, 5.72) before 1995 and an APC of 0.47 (0.06, 0.89) thereafter. Incidence rates were about twice as high for seminomas as for nonseminomas. A trend anal-ysis by age group showed that the highest TGCT incidence rate was observed among men aged 30-40 yr, with a steep increase before 1995.Conclusions: The incidence rate of TGCTs increased in Austria over the past decades and appears to have reached a plateau at a high level. A time trend analysis by age