Retrieval of immature oocytes from unstimulated ovaries followed by in vitro maturation and vitrification: A novel strategy of fertility preservation for breast cancer patients

Background: We report a novel fertility preservation strategy that may be useful for young breast cancer patients who present with time constraints or concerns about the effect of ovarian stimulation. Methods: The protocol involves retrieval of immature oocyte from unstimulated ovaries followed by in vitro maturation (IVM), and vitrification of oocytes or embryos. Results: Thirty-eight patients (age 24 - 45 years) underwent vitrification of oocytes (n = 18) or embryos (n = 20). The mean ages were 33.1 ± 5.0 years and 34.7 ± 4.8 years, respectively. The mean days required to complete the egg collection was 13 days. The median numbers of vitrified oocytes and embryos per retrieval were 7 (range 1 - 22) and 4 (range 1 - 13), respectively. Conclusions: The strategy of immature oocyte retrieval without ovarian stimulation followed by IVM and oocyte or embryo vitrification, which does not increase the serum estradiol level and delay cancer treatment, represents an attractive option of fertility preservation for many breast cancer patients.