Follicular granulosa cells are essential for oocyte growth and maturation. It is postulated that local radiation or systemic chemotherapy is toxic to these cells, causing premature ovarian failure with consequent infertility and premature menopause.
Strategies to avoid these undesirable consequences of cancer treatment include identifying treatment regimes that minimise impact on the ovary, and the cryopreservation of oocytes or ovarian tissue. Each strategy poses specific challenges. Few studies have identified combination regimes that minimise gonadotoxicity (1) or unique targets for minimising follicle depletion. Controlled ovarian hyperstimulation (COH) produces mature, fertilisable oocytes, and subsequent IVF rates of those that survive vitrification (~90%) are similar to fresh oocytes, but an average COH procedure requires 12 days which may be incompatible with treatment, and potentially undesirable in hormone-sensitive cancers. The collection of immature oocytes can occur immediately, but in vitro maturation (IVM) rates are presently too low for clinical application. The IVM, vitrification and IVF of larger metaphase II oocytes has limited clinical success. Autologous transplantation of ovarian tissue has resulted in ~12 births in cancer survivors since 2004 (2) and resumption of menstrual cycles in others. Despite concerns about the lifespan of transplanted tissue and the risk of contamination with haematological malignancies, this emerging technology, as well as advances in IVM, holds promise for the preservation of survivors’ fertility.
We are developing novel methods to improve post-cancer fertility; new vitrification protocols, an innovative modification to ovarian transplantation procedures, and the quantification of patients serum anti-mullerian hormone to test the gonadotoxic potential of specific treatments. A close collaboration between fertility experts and oncologists is required to realise the promise of these novel technologies. This will facilitate the translation of innovative advances in the laboratory into sufficiently powered clinical trials.