Could male infertility contribute to a higher risk for prostate cancer?
Yes, according to new Swedish research that suggests that men who become fathers through assisted reproduction treatments may be more likely to develop prostate cancer in midlife.
The conclusion follows a review of data collected by a Swedish national registry between 1994 and 2014. In all, 1 million children had been born during that time frame, mostly to men in their 30s.
Most (97%) were conceived through natural means. But 1.7% of the fathers (about 20,600 men) had undergone in vitro fertilization, while another 1.3% (nearly 15,000 men) conceived through intracytoplasmic sperm injection (ICSI) techniques.
Prostate cancer risk during the two decades following birth was less than 1% across the board. However, while just 0.28% of dads who had conceived naturally went on to develop the disease, that figure was 0.37% among those from the in vitro group.
Prostate cancer affected an even greater percentage (0.42%) of men in the sperm injection group. The team pointed out that sperm injection is usually reserved for men struggling with the most serious types of infertility.
The findings held up even after taking into account a range of factors, including age, educational background and history of prior cancer.
The team was led by researchers Yahia Al-Jebari, now at Stanford University in California, and Yvonne Lundberg Giwercman, from Lund University in Sweden. In the Sept. 25 issue of the BMJ, they concluded that "men who achieved fatherhood through assisted reproduction techniques, particularly through ICSI, are at high risk for early-onset prostate cancer and thus constitute a risk group in which testing and careful long term follow-up for prostate cancer may be beneficial."
Still, the study authors cautioned that they only tracked prostate cancer risk up to an average age of 45, so the investigation could not assess risk across an entire lifetime. And they stressed that while they identified an association between the two, they did not prove that infertility actually causes prostate cancer.
As to what might explain the link, the study team members noted that prostate cancer and many types of infertility are both related to testosterone levels. It's also possible that both share abnormalities on the male Y chromosome, they said.