The research, lead by Dr Thomas Walsh at the University of California San Francisco, studied data collected from 22,562 male partners of couples seeing fertility treatment in Californian fertility clinics from 1967 to 1998. From this sample, 4,549 of the men were diagnosed with male factor infertility based on a clinical presentation of abnormal semen. These men were linked to the California Cancer Registry and were studied between 1998 and 2004 for any signs to testicular cancer.
By comparing the results of those men with male factor infertility with the rest of the population it was found that men who had the condition were 2.8 times more likely to develop testicular germ cell cancer; 34 of the men seeking infertility treatment were diagnosed with testicular cancer less than a year after seeking infertility treatment.
Although the link has been made between those seeking infertility treatment and the development of testicular cancer, Dr Walsh, now at the University of Washington, and his fellow researches doubted that the link was caused by the infertility treatment itself. It has been hypothesised that certain forms of male infertility are connected with faulty DNA repair, which is also associated with the development of tumours.
Another postulated explanation is that environmental factors could underlie both infertility and testicular cancer. In relation to this possibility it was noted that there has been a continual increase in the incidence of testicular cancer in the last 30 to 50 years. The report observed that 'during the same period there is evidence of a decline in semen quality and fertility in industrialised nations... it is unclear whether the two trends are interdependent or related to one another.'
The report concluded by asserting that more research needed to be done that 'focuses on the etiology of poor germ cell health in these populations.'