Infertile men 2.6 times as likely to have aggressive prostate cancer

Men who have difficulty conceiving children are 2.6 times as likely to have highly aggressive prostate cancer and 60% more likely to have slow-growing tumors, researchers reported Monday. Although the absolute risk of developing prostate cancer was still low in these men, the findings suggest that such men should be screened for prostate cancer at an earlier age, said Dr. Otis Brawley, chief medical officer of the American Cancer Society.

Previous studies have looked at the relationship between prostate cancer and the number of children a man has, but they have produced differing results. Some suggested that fatherhood was protective, while others suggested that it increased risk. Because the number of children a man has may not be an accurate reflector of his fertility, Dr. Thomas J. Walsh of the University of Washington School of Medicine and his colleagues decided to study men who had been evaluated for infertility.

The team studied 22,562 men who had been evaluated from 1967 to 1998 at 15 California infertility centers, comparing them with a similar group of healthy men from the general population. They reported in the journal Cancer that they identified 168 cases of prostate cancer among the men, about the same as the 185 cases that would be expected in a group that size. That suggests that simply being evaluated for infertility does not affect the incidence of prostate cancer.

Overall, 0.4% of the fertile men developed prostate cancer during the decade of follow-up, compared with 1.2% of those diagnosed as infertile. Taking age into account, that translated to a 160% increased risk of developing aggressive tumors and a 60% increased risk of developing slow-growing tumors, the team reported.

It is not clear why infertile men have a higher risk. Walsh speculated that the risk might result from exposure to environmental toxins in the womb that cause damage to the male chromosome, but argued that more research needs to be done, both to confirm their findings and to explore potential mechanisms.

Prostate cancer is the most common cancer in men after skin cancer, striking 192,000 American men each year and killing 27,000. Other risk factors include older age, a family history of the disease, obesity and being African American. Most national organizations now recommend that men be offered screening beginning at age 50, but there is a widespread controversy about this. Some critics argue that the screening leads to an unacceptably high rate of invasive procedures in men who do not have cancer, leading to impotence, urinary incontinence and other problems

Study shows infertile men can be good IVF candidates

Men suffering from from non-obstructive azoospermia (NOA), meaning they have undetectable levels of sperm in their semen, which is not caused by an obstruction in their reproductive system, have long been considered poor candidates for IVF (in vitro fertilisation). However new research published in the online journal of Reproductive Biology and Endocrinology has reported that NOA sufferers could be just as capable of producing viable embryos as other men.

Approximately one per cent of the male population and 10 per cent of men seeking fertility evaluation have testicular failure. Previous research conducted by Belgian scientists reported lower pregnancy rates than normal (approximately 20 per cent) when using sperm from NOA patients. It has also been thought that sperm isolated from NOA patients, while able to produce embryos, is less capable of producing live births and that the incidence of genetic mutations may be higher resulting in congenitial deffects. However, new research contradicts this and gives hope that men with NOA can be just as likely to father a child.

Nina Desai and her team at the Cleveland Clinic Foundation analysed 156 ICSI (intracytoplasmic sperm injection) cycles which used sperm taken from the testes of 44 men suffering from obstructive azoospermia (OA) and 17 men diagnosed with NOA. For their study they assessed embryonic development, implantation, pregnancy and live birth rates. They found on all counts that there were no significant differences between the groups.

Desai and her team analysed the ability for the pateranl sperm to iniate genomic activation, this is when the genome of the embryo divides and begins to arrange itself. They way to morphologically measure this is to observe the degree of cell to cell aderence as the embryo cells divide, if there is genomic activation it is thought that by the eight-cell stage there will be an increase in cell-cell adherence. The anaysis found no differences between the sperm groups suggesting that the genome activation is independent of sperm origin and type of azoospermia. They also noted that there were no cogenital abnormalities in the 115 healthy births.