[OBJECTIVE] Japan's national database of hospital-based cancer registries is estimated to cover ~67% of all new cancer cases. Using this database, we analyzed the characteristics of the recently diagnosed testicular malignancy.
[METHODS] We obtained data for 6510 adult testicular malignancy patients diagnosed in 2012-2015. The distributions of patient ages, histological diagnoses and testicular germ cell tumor hospital care volumes were determined.
[RESULTS] The most common histology was seminoma (60.3% of all testicular malignancies), followed by non-seminoma (24.1%) and diffuse large B-cell lymphoma (13.1%). The median and mean ages of the testicular germ cell tumor patients were high at 38 and 39.8 years, respectively. The age distribution peaked at 30-40 years, followed by 40-50 years. Approximately 18% of testicular germ cell tumor patients were ≥50 years. The ages of the diffuse large B-cell lymphoma patients peaked at 70-80 years (mean 67.7 years). When the analysis was limited to the testicular germ cell tumor patients who received first-course cancer treatment at the participating hospitals, the number of high-volume hospitals with ≥20 testicular germ cell tumor