Boston, MA—Fertility preservation by controlled ovarian hyperstimulation with concurrent letrozole (Femara) is safe in women with breast cancer, according to a single-center, prospective study on the long-term safety of fertility preservation by the use of ovarian stimulation and concurrent aromatase inhibitors in women with breast cancer, presented at the 2015 Best of ASCO meeting in Boston. Controlled ovarian hyperstimulation had no impact on relapse-free survival and enabled live births in a substantial proportion of women who later chose to retrieve their frozen embryos or oocytes.
“Many young women with breast cancer are concerned about fertility, yet very few of them actually undergo fertility preservation. This study should be reassuring to those young women, and it should make us aware of the need to refer appropriate patients for fertility preservation early in the course of breast cancer treatment,” said Karen L. Smith, MD, MPH, Clinical Associate, Breast Cancer Program, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore. Patients with estrogen receptor (ER)-negative disease “are at increased risk for recurrence, and these patients need to be followed more closely,” Dr Smith added.
The relapse-free survival was similar in women who underwent controlled ovarian hyperstimulation and those who did not, and was also similar regardless of BRCA status, ER status, and the timing of ovarian stimulation (before or after breast cancer surgery).
The options for fertility preservation in the large population of young women with breast cancer include the cryopreservation of oocytes or embryos. Ovarian hyperstimulation is used to produce oocytes. However, concerns about ovarian hyperstimulation in women with breast cancer because of increased estrogen levels have led to the use of concurrent letrozole therapy to modify the estrogen levels.
A prospective study was conducted at a single institution to evaluate the safety of controlled ovarian hyperstimulation in 337 women with breast cancer who consulted a fertility specialist between 2002 and 2014 and were offered controlled ovarian hyperstimulation for embryo or oocyte preservation. Of these, 120 women opted to undergo controlled ovarian hyperstimulation, and the 217 women who did not served as the controls.
The main objective was to determine the long-term impact of controlled ovarian hyperstimulation on breast cancer outcomes in patients who received concurrent letrozole therapy. The impact of BRCA mutations, ER status, and the timing of controlled ovarian hyperstimulation on the outcomes were analyzed.
The groups with and without controlled ovarian hyperstimulation were well-balanced for the demographic and disease characteristics, with the exception of having more younger and node-positive patients in the group with controlled ovarian hyperstimulation.
At a mean follow-up of 5 years, no significant difference in relapse-free survival was observed between the patients who underwent fertility preservation with controlled ovarian hyperstimulation and those who did not. The relapse-free survival was similar in a subgroup analysis of BRCA status, ER status, and the timing of fertility preservation.
Of the 131 women with breast cancer who opted to freeze their embryos over the 12-year period, 33 patients returned to undergo implantation of their frozen embryos either in themselves (N = 18) or in a gestational carrier (N = 15). Of these 33 women, 17 (51.5%) had ≥1 live births. The rate of live births is similar to that of age-matched controls without breast cancer in a national in vitro fertilization database. No breast cancer recurrences were reported in the women who conceived a child.