Late relapse of testicular cancer.

Due to its unique biological behavior, late relapse (LR) of testicular cancer has recently been described as an own tumor entity. It is currently defined as tumor recurrence more than 2 years after complete remission following primary treatment including chemotherapy. The incidence ranges from 2 to 6%, with a median relapse-free interval of 5.4-7.1 years from the initial treatment. Although histology shows a germ cell tumor (GCT) origin, the clinical biology is different. The dominant characteristics are slow tumor growth and chemoresistance. Molecular analysis currently focuses on the mechanisms of drug resistance. The initial response to chemotherapy is less than 30% and in most cases complete surgical resection remains the only treatment option with favorable long-term results. The most common site of LR is the retroperitoneum, with undifferentiated cancer (yolk sac) being the most frequent histology. In most cases, patients have already undergone previous retroperitoneal surgery. The overall cure rate is only about 50%, hence, adequate treatment of the primary tumor is essential to prevent the development of LR.