According to a recent study conducted by the National Cancer Institute, the use of the popular fertility drug Clomid does not result in a higher risk of breast cancer. This is reassuring news for many women who may have been concerned that taking fertility drugs could lead to an increased risk of the disease.
We asked Dr. Donesky to share his thoughts on the study and its findings. He says, “The lack of correlation with clomiphene (Clomid) and breast cancer is not surprising, as clomiphene and tamoxifen (used to help prevent the recurrence of breast cancer) are closely related medications. They are structurally very similar and are both members of a class of medications called selective estrogen receptor modulators, or SERMs.”
The study only revealed an increased risk of breast cancer in women who took 12 or more cycles of the drug. Researchers admit that this increase could be due to prolonged infertility rather than the medication itself.
As for the Fertility Center’s approach to treating patients with Clomid, Dr. Donesky notes, “It is important that we actively manage infertility patients and not just keep repeating the same treatments over and over. Almost 90% of the pregnancies we will ever see from a given treatment will have already occurred within four months, so there is little reason to keep women on clomiphene for 12 months.”
He also adds, “We should not have women on clomiphene until we know the status of the fallopian tubes and the partner’s sperm. We would not want to expose women to Clomid until we know everything is in order for a successful conception.”
At the Fertility Center, diagnostic tests, such as an HSG and semen analysis, are used to determine the potential for successful conception before any medications are prescribed.
These findings from the National Cancer Institute follow a 2009 study that showed no increased risk of ovarian cancer in women who took fertility drugs. Dr. Donesky notes, “For ovarian cancer, we have known for some time that, while women with infertility inherently have a higher risk of ovarian cancer, that risk does not seem to be increased by judicious use of fertility medications. Our beliefs about ovarian cancer have had to change dramatically in the last couple of years as it has been shown that most cancers actually start in the fallopian tubes and not in the ovaries at all.”
The results of these studies reiterate the fact that shorter-term use and careful monitoring are essential when using fertility drugs. “What the data shows is that short-term use of these medications (12 months and probably up to two years) is safe, but with longer-term use, that confidence declines,” Dr. Donesky says.
Regarding Clomid specifically, with fewer cycles and lower doses becoming the norm, women should feel confident that there is no significant link between the drug and increased breast cancer risk.