Q:My husband and I are contemplating vasectomy as a form of contraception. What disturbs me is that I have heard about possible links between this operation and cancer, but am having trouble finding evidence to support this. Our doctor seems to think there isn't any. Is he right? T R, Dundee..........
Somewhere in the region of 50 million couples around the world rely on vasectomy for contraception, so any health risks related to the operation have potentially far reaching consequences. The operation which can be performed under a local anesthetic, involves the cutting and tying of the vasa deferentia the two tubes passing from the testicles to the seminal vesicles (where sperm is "stored" ready for ejaculation). This has led to it being known as "the snip" which serves to trivialize many of the problems which can follow the procedure.
After the operation a store of sperm is left beyond the block, so the man will not be sterile until all the sperm have been ejaculated which can take up to two months. Even after this, there is some concern about the 100 per cent effectiveness claim for the operation since there have been reports of spontaneous reversal years after the operation. However, this is a rare occurrence. What observers are now more worried about is the link between vasectomy and cancer.
Originally it was thought that there might be a link between vasectomy and heart disease. One of the biological effects of the operation is that, in two thirds of men, antibodies to sperm are formed and may persist for a number of years. The implications are unknown, and for a time it was thought that the immune complexes formed from the antibodies could injure the arterial walls and bring on hardening of the arteries and thus heart disease. This has never been conclusively proved.
What has been demonstrated in some studies is a link between vasectomy and prostate cancer. Two US studies have shown that vasectomized men have a 60 per cent greater risk of prostate cancer (JAMA, 1993; 269(7): 878-82; Lancet May 21, 1992). The risk appears to persist even when findings are adjusted for a man's body size, cigarette and alcohol consumption, marital status and even level of education. Other studies, such as the one done by the Boston University School of Medicine which looked at data collected between 1976-1988, confirm this finding and suggest the risk may be as great as between three and five times that for unvasectomized men (Am J Epidemiol, 1990; 132: 1051-5).
What has also been shown is that the likelihood of developing prostate cancer increases with the time elapsed since the operation (Br J Cancer, 1988; 57: 326-31). Risk also increases if the man is a smoker or had his first sexual experience at an early age. It has been hypothesized that the immune system response after a vasectomy may possibly have an influence on the development of cancer. In addition, researchers have speculated that cancer may be triggered by a reduction in the secretion of prostatic fluid which follows vasectomy (Lancet, Feb 20, 1993). Vasectomy is known to raise serum testosterone levels, and this appears to have a link with prostate cancer (Am J Epidemiol, 1981; 130: 829).
There is also a possible link with testicular cancer (BMJ, 1976; i: 621-2; BMJ, 1992; 304: 729-30), though the link is harder to prove because the rarity of the disease means study groups are small.
There are also studies which do not show an increased risk of cancer or any other disease associated with vasectomy (BMJ, 1992; 304: 743-6). In other studies the link is less clear, and there have been many suggestions that those studies into the link between vasectomy and cancer have not, in the main, been well designed, as there have been suggestions that testicular cancer may have been present at the time of the operation, which is why it was detected so soon afterwards (Am J Epidemiol, 1986, 124: 39-52; Br J Cancer, 1987; 55: 97-103).
Besides these possible dangers, there is also the potential of side effects from the operation, or what is called post vasectomy syndrome. In one British study of 172 men surveyed, 26 reported having pain four years later. In another study, men undergoing vasectomy were three times more likely to have bouts of epididymitis or prostatitis (Second Opinion, Sept 1996).
Is a vasectomy reversal the answer? If you are in otherwise good health, probably not. You may be at more risk from the operation than you are from cancer. It would be better to take some positive health steps such as stopping smoking, eating a wholefood diet, reducing alcohol consumption and taking anti oxidizing nutritional supplements. If, however, you want to reverse the operation because you wish to father a child there is evidence of success (B J Urol, 1994; 73: 337-44). If it was only three years since the operation you have a 75 per cent chance of success. This declines to 50 per cent after eight years and 30 per cent after 15 years.