Second malignancies following pure seminoma

Second malignancies in patients with pure testicular seminoma were studied in order to look for adverse late effects of treatment and to study the significance of second malignancies during follow-up.

In a multicentric investigation, 839 consecutive patients with pure testicular seminoma were observed for a median follow-up of 3.9 years. Thirty-seven patients had been excluded from the study because they already had had either a contralateral testicular germ cell tumor or another malignancy. 758 patients received radiotherapy, 76 underwent chemotherapy, 5 had surveillance only. The expected rate of second cancers was calculated according to the data of the cancer registry of Saarland, Germany.

Twenty-two second cancers (13 contralateral testicular tumors, 9 extratesticular malignancies) were recorded. The overall risk of having a second cancer was RR = 4.8 (95% CI 3. 0-7.3). The risk of having a subsequent testicular tumor is RR = 44. 8 (95% Cl 23.9-76.7). 1.1% of the patients developed a nontesticular second tumor. The risk of having a nontesticular second cancer is RR = 2.1 (95% CI 1.0-4.0). A significantly increased risk was observed for renal cell cancer as well (RR = 12.5; 95% Cl: 1.5-45.1). Increased RR without reaching statistical significance were found for rectal cancer (RR = 5.0; 95% Cl: 0.1-27.9) and non-Hodgkin lymphoma (RR = 6.7; 95% CI 0.2-37.1). None of the second cancers were directly located within the radiation field; 5 neoplasms arose at the border of the radiation field.

This study confirmed the increased risk of having a second testicular germ cell cancer. There is also a small but definitely increased overall risk of having a nontesticular second cancer. Treatment-unrelated factors - possibly genetic predisposition - must be considered for a substantial number of these second tumors, since in the present study the follow-up was rather short and most of the second cancers were located outside of the radiation fields. In particular, the association of renal cancer with testicular cancer appears to be a more than chance occurrence. Second cancer is a real hazard following treatment of testicular cancers and should always be considered during follow-up.