Strong familial associations between seminoma and other cancer types
While nonseminoma testicular cancer (TC) has a stronger genetic background, seminoma appears to have more familial associations with discordant cancers, a recent study has found.
Drawing from the Swedish Family-Cancer Database, researchers identified 11,138 TC patients, in whom seminomas were more common than nonseminomas (6,120 vs 4,729 cases). There were 9,711 participants in the offspring generation.
A total of 191 TC cases were identified in the offspring generation (2.0 percent). The overall relative risk (RR) for TC was 5.06 when one proband was diagnosed with the condition and 18.23 when two probands had the condition.
In terms of TC type, the RR for seminoma with one proband was 5.55, while the corresponding value for nonseminoma with one proband was 4.46. Only four cases of nonseminoma with two probands were reported, and the resulting RR was 33.59.
Other cancers in the family members also affected the risk of TC in the offspring generation. The likelihood of TC was increased when family members had diagnoses of melanoma (RR, 1.24) or of lung (RR, 1.11), breast (RR, 1.09) and nervous system (RR, 1.17) cancers. The reverse was also true: the risk of breast cancer and melanoma in the offspring was higher when family members were diagnosed with TC.
Similarly, the presence of discordant cancers in family members increased the risk of testicular seminoma in the offspring generation. Among these discordant cancers were pancreatic (RR, 1.25), endometrial (RR, 1.25) and lung (RR, 1.15) cancers, along with Hodgkin lymphoma (RR, 1.48).
In contrast, no such effect of discordant cancers in the family members was observed on the risk of nonseminoma TC in the offspring generation.