One of the concerns many women have when undergoing fertility treatment is the possibility that fertility treatments could enhance their chances of developing cancers later in life. There is much truth and myth involved in this question. For the most part, fertility treatments are very safe, in particular when they are administered by a reproductive endocrinologist. However, there are certain concerns that occur.
Medications that can induce multiple ovulations to occur can, at least in theory, increase the chances of ovarian cancers developing later in life. There's also the concern that perhaps breast or colon cancers can be increased. In fact, the data to date indicates that there is no concern for an increase in breast cancer or colon cancer or any other cancer from fertility medications with the exception of a certain type of ovarian cancer.
Ovarian cancer is very dangerous, in particular, because it tends to be very invasive. It can affect other organs later in life, and the death rate is very high. However, fertility medications have not been shown in the vast majority of people to increase the chances of invasive cancers of the ovary.
However, there are data to suggest that there is an increase of what are called borderline tumors of the ovary in women who use fertility medications. Those borderline tumors are tumors that are in fact malignant, but tend to not spread and result in an ovarian mass that is often excised surgically when it occurs. However, when looking at the data carefully, it appears that the chances of developing borderline tumors of the ovary are extremely low, even in women who have used long-term fertility treatment.
It's also important to separate infertility from treatment as a cause for ovarian cancer. There are data that suggest that women who have long-standing infertility are at risk of ovarian cancer at rates higher than women who do not have fertility issues. As a result, those women are going to have higher rates despite having treatment.
In general, the risks of fertility medications are low. These are safe medications. The chances of cancer are increased slightly for borderline tumors of the ovary, but there do not appear to be an increase in the risk of any invasive cancers from fertility treatments.