Causes of inferior relative survival after testicular germ cell tumor diagnosed 1953-2015: A population-based prospective cohort study.

RS declines mainly from TC deaths <5 years after TGCT diagnosis. Later, excess SC mortality becomes particularly important, reducing RS even ≥26 years. Radiotherapy; standard adjuvant seminoma treatment 1980-2007, is likely an important contributor, as are chemotherapy and possibly innate susceptibilities. Vigilant long-term follow-up, including psychosocial aspects, is important. Further research should focus on identifying survivor risk groups and optimizing treatment.