Response to ovarian stimulation in patients facing gonadotoxic therapy
Chemotherapy naive patients undergoing embryo/oocyte banking for fertility preservation (FP) were assessed for response to ovarian stimulation. Fifty FP patients facing gonadotoxic therapy were matched by age, race, cycle number, date of stimulation and fertilization method to patients undergoing IVF for infertility or oocyte donation. There were no differences in baseline FSH, anti-Mullerian hormone, antral follicle count and total gonadotrophin dose. FP patients had more immature oocytes (2.2 versus 1.1; P = 0.03) and lower fertilization rates per oocyte retrieved (52% versus 70%; P = 0.002). There were no differences in numbers of oocytes retrieved, mature oocytes or fertilized embryos. Subgroup analysis revealed that FP patients taking letrozole required higher gonadotrophin doses (3077 IU versus 2259 IU; P = 0.0477) and had more immature oocytes (3.4 versus 1.2; P = 0.03) than matched controls. There were no differences in gonadotrophin dose or oocyte immaturity among FP patients not taking letrozole. Overall, chemotherapy naive FP patients had similar ovarian reserve, response to stimulation and oocyte and embryo yield compared to controls. Patients who received letrozole required higher gonadotrophin doses and produced more immature oocytes, suggesting that response to ovarian stimulation may be impaired in patients with hormone-sensitive cancers receiving letrozole.