Medical Q&As

Testicular cancer - risk for brothers?

My brother was recently diagnosed with testicular cancer. Is there any increased risk for siblings where there is a history of this type of cancer?

The main risk factors for carcinoma of the testicle are undescended testicle, atrophy of the testicle and a family history of the disease. Researchers have identified a gene that can predispose to the development of testicular cancer but the cancer does not develop in every case where that gene is present. It is postulated that some other factors must be present in order for the tumour to develop. It has been established that in the case of male twins the risk of testicular cancer developing in the second twin is of the order of a 2% risk. That risk would be lower for a non-twin male sibling but would be higher than the risk that exists in the general population. It is difficult to accurately quantify the magnitude of that risk but it would be less than the 2% risk that exists with twins. Therefore there is an increased risk of the cancer occurring but the probability of that happening would be less than 1%.