Ovarian stimulation using gonadotropins and letrozole to preserve fertility in patients with breast cancer undergoing chemotherapy is unlikely to increase their risk for recurrence, say US researchers.
Kutluk Oktay, from the Center for Human Reproduction in New York, and colleagues evaluated 215 women with breast cancer for fertility preservation before adjuvant chemotherapy. Overall, 79 of the women underwent controlled ovarian stimulation (COS) for embryo or oocyte preservation, while the remainder served as controls.
An average of 10.3 oocytes were retrieved from COS patients, with 5.97 embryos or oocytes cryopreserved per patient.
The time between surgery and chemotherapy was significantly longer for patients who underwent IVF than control patients, at 45.08 versus 33.46 days. In patients who had COS, peak estradiol levels ranged from 58.4 to 1,166 pg/ml.
In the COS group, median follow-up after chemotherapy was 23.4 months, compared with 33.05 months in the control group. Recurrence occurred in 3.8 and 8.1 percent of COS and control patients, respectively, at a nonsignificant hazard ratio of 0.56.
The team concludes: “COS before embryo or oocyte cryopreservation is unlikely to result in a significant increase in recurrence of breast cancer compared with those who did not undergo ovarian stimulation, at least in the short term.”