Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)
The diagnosis of seminoma requires that the serum alpha fetoprotein (AFP) be normal, and no other germ cells be present. Management decisions in patients presenting with these tumors can sometimes be difficult.
Extragonadal germ cell tumors can be benign (teratoma) or malignant. The latter group can be divided into seminoma and nonseminoma germ cell tumors, which include the following:
Endodermal sinus tumors.
Mixed germ cell tumors.
Extragonadal germ cell tumors occur much more commonly in males than in females  and are usually seen in young adults. They are aggressive neoplasms and can arise virtually anywhere, but...
As in testicular seminoma, these tumors are very radiosensitive. About 60% to 80% of patients will remain disease free after treatment with radiation therapy. Craniospinal radiation therapy for intracranial germinomas (the intracranial counterpart of seminoma) is associated with relapse-free and overall survival rates of 90% to 95% at 5 years, as evidenced in the GER-GPO-MAKEI-86/89 trial, for example.[Level of evidence: 3iiiA]
Initial chemotherapy with regimens used in nonseminoma testicular cancer is also very efficacious. Practically speaking, patients with localized relatively small tumors are usually treated initially with radiation, while those with very bulky tumors or nonlocalized tumors are treated with etoposide-based and cisplatin-based chemotherapy regimens.
As in testicular seminoma, many patients will be left with a residual mass posttreatment. If the residual mass is smaller than 3.0 cm, the majority of experts agree that observation is appropriate. In those with larger residual masses, some experts favor surgical excision while others favor observation.[3,4]
Current Clinical Trials
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with extragonadal seminoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.