Stimulation of the ovaries in women with breast cancer undergoing fertility preservation: Alternative versus standard stimulation protocols; the study protocol of the STIM-trial.

BACKGROUND: Chemotherapy for breast cancer may have a negative impact on reproductive function due to gonadotoxicity. Fertility preservation via banking of oocytes or embryos after ovarian stimulation with FSH can increase the likelihood of a future live birth. It has been hypothesized that elevated serum estrogen levels during ovarian stimulation may induce breast tumour growth. This has led to the use of alternative stimulation protocols with addition of tamoxifen or letrozole. The effectiveness of these stimulation protocols in terms of oocyte yield is unknown. METHODS/DESIGN: Randomized open-label trial comparing ovarian stimulation plus tamoxifen and ovarian stimulation plus letrozole with standard ovarian stimulation in the course of fertility preservation. The study population consists of women with breast cancer who opt for banking of oocytes or embryos, aged 18-43years at randomisation. Primary outcome is the number of oocytes retrieved at follicle aspiration. Secondary outcomes are number of mature oocytes retrieved, number of oocytes or embryos banked and peak E2 levels during ovarian stimulation. DISCUSSION: Concerning the lack of evidence on which stimulation protocol should be used in women with breast cancer and the growing demand for fertility preservation, there is an urgent need to undertake this study. By performing this study, we will be able to closely monitor the effects of various stimulation protocols in women with breast cancer and pave the way for long term follow up on the safety of this procedure in terms of breast cancer prognosis. TRIAL REGISTRATION: NTR4108.

A mother's gift of life: exploring the concerns and ethical aspects of fertility preservation for mother-to-daughter oocyte donation.

With the introduction of oocyte vitrification, a special form of intergenerational intrafamilial medically assisted reproduction (IMAR) has now become feasible: fertility preservation for mother-to-daughter oocyte donation (FPMDD). For girls diagnosed with premature ovarian insufficiency (POI), banking of their mothers' oocytes can preserve the option of having genetically related offspring. Since policy documents on IMAR do not discuss specific concerns raised by FPMDD, clinicians can feel at a loss for guidance with regard to handling these requests. Through a comparison of FPMDD with reproductive practices in which similar concerns were raised, proportionality of cryopreservation for self-use and pressure to use the oocytes in fertility preservation in minors, we argue that FPMDD can be acceptable under conditions. The paper ends with recommendations for handling FPMDD-requests, including different options for the legal construction of this form of oocyte donation.

A prospective case series of women with estrogen receptor-positive breast cancer: levels of tamoxifen metabolites in controlled ovarian stimulation with high-dose tamoxifen.

Controlled ovarian stimulation (COS) in women with estrogen receptor (ER)-positive breast cancer is potentially harmful because of the increase in serum estrogen levels. During COS for cryopreservation of oocytes or embryos, these women may receive high doses of tamoxifen (60 mg) to modulate the ER and prevent extra growth of estrogen responsive tumours during COS. However, it is unknown whether adequate serum concentrations of endoxifen, the most important metabolite of tamoxifen, can be reached. The aim of this study is to evaluate whether the tamoxifen dose used in a tamoxifen-COS combined schedule for women with ER-positive breast cancer is high enough to reach endoxifen levels that are considered therapeutically effective to inhibit breast cancer growth. The four women with ER-positive breast cancer who underwent COS for cryopreservation of oocytes were prospectively studied at the Academic Medical Centre, Amsterdam, the Netherlands. Throughout COS, blood samples were collected and tamoxifen and endoxifen levels were determined by a validated high-performance liquid chromatography tandem mass spectrometry assay. The four women with ER-positive breast cancer underwent a total of five COS cycles, while additionally using tamoxifen 60 mg daily. The tamoxifen and endoxifen levels showed a large variability between the women, with endoxifen levels during the whole period of ovarian stimulation varying between 3.96 and 41.0 ng/ml. The average number of vitrified oocytes was 11 (5-14). Therapeutically effective endoxifen serum levels can be reached when tamoxifen is used to counteract estrogen levels during COS for fertility preservation, but not in all women. Large variations of tamoxifen and endoxifen levels between the women were observed.