[Late toxicity after chemotherapy of malignant testicular tumors]

Improved survival in testicular cancer has been accompanied by concern about long-term side effects of chemotherapy or radiotherapy. Secondary malignant neoplasia represents one of the worst possible long-term complications, leading to death in patients cured of their primary malignancy. Patients with testicular germ cell tumors appear to have a 2-fold increased risk of developing any second cancer 25-30 years after the diagnosis, resulting in a cumulative incidence of 16-23% at that time. The risk for secondary solid tumors can be mainly attributed to radiotherapy. There is strong evidence of an increasing risk for secondary solid tumors with time since treatment. Tumor-specific analysis of the risk for second cancers revealed statistically significant excesses for stomach, pancreas, bladder, rectum, prostate, and kidney cancer, as well as for cancer of the thyroid, melanoma, sarcomas, and non-Hodgkin's lymphoma. No significantly elevated risk for secondary solid tumors was observed after treatment with chemotherapy alone. The risk of secondary leukemia was associated with both radiotherapy and in particular with chemotherapy. In recent clinical surveys of patients with testicular cancer, estimates of the risk of leukemia after chemotherapy have ranged from 10- to 300-fold. An elevated risk was observed within the first two decades after diagnosis, later the risk was as expected in the normal population. Etoposide seems to be leukemogenic, especially at cumulative doses higher than 2 g/m2, although the effects of dose and schedule as well as the effects of other cytotoxic agents and radiotherapy remain to be finally clarified. Based on currently available data in patients with testicular cancer, it can be concluded that a significant elevated risk for the development of secondary leukemia exits after chemotherapy. However this risk does by far not outweigh the therapeutic benefit of etoposid-based therapy in patients with germ cell tumors. Secondary Raynaud's phenomenon is the main late vascular toxicity affecting about one third of patients after curative chemotherapy for testicular cancer. Hypertension will occur in one fifths of the patients. The incidence of vascular toxicity appears to be lower following PEB-therapy compared to PVB-therapy and major vascular events seem to be rare. Other frequent symptomatic toxicities are ototoxicity and peripheral neuropathy. A major risk factor for the development of toxicity is the cumulative dose of cisplatin given. Alterations of gonadotropin levels and Leydig cell insufficiency persist in more than half of young patients cured from testicular cancer by cisplatin-based combination chemotherapy. Approximately one fourth of patients have low serum magnesium or phosphat levels, or elevated creatinine levels. These toxicities seldomly result in clinical symptoms. We conclude that 3-4 courses with bleomycin, cisplatin and etoposide in testicular cancer patients will only rarely lead to symptomatic impairment of organ functions and a decrease of quality of life. Germ cell cancers have served as a valuable model for the development of new treatment strategies contributing largely to defining the role of cisplatinum, etoposide and recently ifosfamide in medical oncology. However, germ cell cancer may also be a useful model for investigating the long term side effects of the oncological therapies. Thus, germ cell cancer is not only a "model for a curable neoplasm" (L.H. Einhorn) but can also be seen as a "model for the study of late sequelae of modern oncological therapies".