[Infertility, fertility treatment and breast cancer risk]

Breast cancer is the most common cancer in women in Israel and throughout the world. It is the leading cause of death from cancer in women. The cause of breast cancer is unknown; however gynecological history and hormonal factors have a major impact on the risk to develop breast cancer. Infertility affects 15-20% of couples in developed countries and most of them will need fertility treatment. The variety of fertility treatments and their use has been widespread during the last 50 years and especially since the introduction of in vitro fertilization. During fertility treatment, and depending on the type of treatment, there is ovarian hyperstimulation with maturation of several follicles and higher than normal estradiol levels. This article reviews the leading studies that evaluated the possible link between fertility treatment and the development of breast cancer. Most studies showed no association between fertility drugs and breast cancer. Whereas other researchers demonstrated a possible link between some fertility drugs and increased risk for breast cancer in certain subgroups. Therefore, larger studies with longer follow-up periods and better control for all possible confounding factors are needed in order to confirm the safety of fertility treatments in the long run. The combination of infertility and fertility treatment might cause harm, such as an increased risk for breast cancer Therefore, one has to consider carefully, together with the woman, the need for fertility treatment and give the lowest possible dosage for the shortest duration in order to minimize the risk.