Fertility Drugs do not increase the risk for ovarian cancer
Fertility Drugs do not increase the risk for ovarian cancer
Physicians and patients are both interested in identifying factors that may increase the risk for the development of ovarian cancer. One of the leading established risk factors for ovarian cancer has been whether or not a woman has been pregnant. Women that have never delivered a baby seem to have a higher risk of ovarian cancer than women who have delivered a baby. Women with infertility were also thought to be at higher risk for ovarian cancer.
In recent years, studies have brought up concerns regarding women treated with fertility drugs, in particular for women who had never been pregnant and for those who used the drugs long term. However, several subsequent studies were reassuring as they did not confirm a strong link between ovarian cancer and the use of fertility drugs.
The two most recent studies, showed no overall increase in the incidence of ovarian cancer after use of clomiphene citrate or gonadotropins.
It should be noted, however, that most of these studies were not able to distinguish the possible effects of fertility medications from the underlying causes of infertility, which could independently affect the risk of ovarian cancer.
In order to make a convincing argument that any factor causes an increase in the risk of cancer, scientists would like to see several things:
- The relationship makes sense - Two theories are usually used to explain how fertility drugs might affect the risk of ovarian cancer. The continual ovulation theory suggests that repeated, uninterrupted ovulation causes trauma to the surface of the ovaries, leading eventually to a cancerous change. The gonadotropin theory suggests that exposure of the ovaries to the hormones contained in fertility drugs could stimulate the development of cancer as well.
- Dose response effect – This means that if “Drug X” causes ovarian cancer, then women who take a higher dose of “Drug X” or take it for a longer period of time should develop cancer more often. Previous studies were criticized because of the absence of a dose-response effect.
- Latency effect – It may take many years for cancer to start and develop to a point where it can be diagnosed. Most women are diagnosed with ovarian cancer in their fifties and sixties. If “Drug X” causes ovarian cancer, than the longer you observe women after taking “Drug X”, the more should be found to have it.