Male infertility: Increased cancer risk found in families of men with low sperm count

Researchers have detailed the risk patterns of cancers in families of men producing fewer or no sperms in a new study using genetic sequencing.

They found that in families of men producing no sperm (azoospermic), the risk of developing cancers of bone and joint increased by 156 per cent, while that of developing cancers of lymph, soft tissue, and thyroid increased by 60 per cent, 56 per cent and 54 per cent, respectively.

The researchers, led by those at the University of Utah, US, also found that families of men severely oligozoospermic – having a low sperm count of less than 1.5 million per millilitre of semen – were at 143 per cent heightened risk of having bone and joint cancer and 134 per cent heightened risk of having testicular cancer.

“Our study identified several unique patterns of cancer risk in families of men with poor fertility. When family members share cancer risk patterns, it suggests that they have genetic, environmental, or health behaviours in common. Genetic and environmental exposures can also act together to increase cancer risk,” said Joemy Ramsay, assistant professor at the University of Utah, and lead author of the study published in the journal Human Reproduction.

The findings could improve their understanding of the biological mechanisms involved in both cancer and infertility, the researchers said.

This would enable doctors to more accurately predict cancer risk for subfertile men and their families, and improve the counselling that could be offered to them, they said.

For the study, the researchers took results obtained by performing semen analyses of 786 men attending fertility clinics in the US state of Utah between 1996 and 2017. They matched these men with information of 5674 fertile men in the general population (having at least one child).

The team also used the Utah Population Database and the Utah Cancer Registry for collecting health data on the men’s relatives and cancer diagnoses, respectively.

The researchers simultaneously assessed the risk of multiple cancer types within each family and then performed a cluster analysis – a data analysis technique – to identify groups of families with similar patterns of risk for multiple cancers.

While previous research has shown that male infertility is linked to an increased risk of cancer in them and their families, the results have been inconsistent, the researchers said, with the risks of various cancer types differing considerably between family groups and with the type of infertility.

“This is the first study to describe these multicancer patterns in families of subfertile men,” said Ramsay.

The researchers acknowledged that the study’s limitations included lack of information on other health conditions of the men, their lifestyle risk factors (smoking and BMI), and exposure to environmental risk factors among the subfertile men.

They also noted that the men studied were those seen at a fertility clinic and, therefore, likely represented a subset of the overall population of subfertile men.