Risk of prostate cancer for men fathering through assisted reproduction: nationwide population based register study

OBJECTIVE: To compare the risk and severity of prostate cancer between men achieving fatherhood by assisted reproduction and men conceiving naturally. DESIGN: National register based cohort study. SETTING: Sweden from January 1994 to December 2014. PARTICIPANTS: 1 181 490 children born alive in Sweden during 1994-2014 to the same number of fathers. Fathers were grouped according to fertility status by mode of conception: 20 618 by in vitro fertilisation (IVF), 14 882 by intra-cytoplasmic sperm injection (ICSI), and 1 145 990 by natural conception. MAIN OUTCOME MEASURES: Prostate cancer diagnosis, age of onset, and androgen deprivation therapy (serving as proxy for advanced or metastatic malignancy). RESULTS: Among men achieving fatherhood by IVF, by ICSI, and by non-assisted means, 77 (0.37%), 63 (0.42%), and 3244 (0.28%), respectively, were diagnosed as having prostate cancer. Mean age at onset was 55.9, 55.1, and 57.1 years, respectively. Men who became fathers through assisted reproduction had a statistically significantly increased risk of prostate cancer compared with men who conceived naturally (hazard ratio 1.64, 95% confidence interval 1.25 to 2.15, for ICSI; 1.33, 1.06 to 1.66, for IVF). They also had an increased risk of early onset disease (that is, diagnosis before age 55 years) (hazard ratio 1.86, 1.25 to 2.77, for ICSI; 1.51, 1.09 to 2.08, for IVF). Fathers who conceived through ICSI and developed prostate cancer received androgen deprivation therapy to at least the same extent as the reference group (odds ratio 1.91; P=0.07). CONCLUSIONS: Men who achieved fatherhood through assisted reproduction techniques, particularly through ICSI, are at increased 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.