Do survivors of childhood cancer have increased incidence of premature menopause?

Fertility preservation in young females with hematological malignancies

Impaired reproductive function and possible infertility are major concerns in long-term survivors of hematological malignancies. The ongoing increase in the survival rates of these patients is therefore accompanied with a growing demand for effective, safe and specifically tailored fertility preservation options. When approaching patients facing hematological malignancy, an individual evaluation of potential infertility risks and possible preventive or preserving measures should be performed. This review aims to provide up-to-date knowledge on female reproductive risks, and ovarian, uterine and genital injuries associated with therapy regimens currently used in hemato-oncological disorders. Recent progress in fertility preservation methods including ovarian tissue cryopreservation and transplantation, egg and embryo freezing, ovarian transposition and their specific role in hematological disorders are presented. The efficacy of these methods, possible risks and future challenges are critically discussed.

Preservation of ovarian function and fertility despite gonadotoxic chemotherapy

The author aims to review the various strategies and avenues for fertility preservation despite gonadotoxic chemotherapy in young women. The recent increase in the survival of young patients has increased the worldwide attempts toward fertility preservation. The currently utilized methods are sperm cryopreservation and banking in male patients, and cryopreservation of embryos, unfertilized oocytes and ovarian tissue, as well as administration of gonadotropin-releasing hormone agonists (GnRH-a) before and during the gonadotoxic chemotherapy in young female patients. For those patients in whom pelvic irradiation is planned, ovariopexy is suggested. Since none of the suggested methods are ideal and none guarantees future fertility, a combination of several methods may optimize patients' chance of fertility preservation. GnRH-a co-treatment may reduce ovarian damage significantly in female patients treated with gonadotoxic chemotherapy. GnRH-a should be considered for women of reproductive age receiving gonadotoxic chemotherapy in addition to assisted reproduction and cryopreservation of embryos, oocytes and ovarian tissue.

Chemotherapy and fertility

The overall increase in cancer prevalence and the significant increase in long-term survival have generated worldwide interest in preserving fertility in young women exposed to gonadotoxic chemo- and radiotherapy. Infertility represents one of the main long-term consequences of combination chemotherapy given for lymphoma, leukaemia and other malignancies in young women. The gonadotoxic effect of various chemotherapeutic agents is diverse, may involve a variety of pathophysiologic mechanisms, and is not unequivocally understood. Proliferating cells, such as in tissues with high turnover (i.e. bone marrow, gastrointestinal tract and growing ovarian follicles) are more vulnerable to the toxic effect of alkylating agents. These agents may also be cytotoxic to cells at rest, as they are not cell-cycle specific. Alkylating agents, the most gonadotoxic chemotherapeutic medications, cause dose-dependent, direct destruction of oocytes and follicular depletion, and may bring about cortical fibrosis and ovarian blood-vessel damage. The reported rate of premature ovarian failure after various diseases and chemotherapeutic protocols differ enormously, and depend mainly on the chemotherapeutic protocol used and age range of the woman. Several options have been proposed for preserving female fertility, despite gonadotoxic chemotherapy: ovarian transposition, cryopreservation of embryos, unfertilised metaphase-II oocytes and ovarian tissue, and administration of gonadotropin-releasing hormone agonistic analogs in an attempt to decrease the gonadotoxic effects of chemotherapy by simulating a prepubertal hormonal milieu. None of these methods is ideal and none guarantees future fertility in all survivors; therefore, a combination of methods is recommended for maximising women's chances of future fertility.

Preservation of ovarian function and minimizing premature ovarian failure during chemotherapy using gonadotropin-releasing hormone analogs

Evaluation of: Del Mastro L, Boni L, Michelotti A et al. Effect of the gonadotropin-releasing hormone analogue triptorelin on the occurrence of chemotherapy-induced early menopause in premenopausal women with breast cancer: a randomized trial. JAMA 306(3), 269-276 (2011). This study is a randomized, open-label, Phase III trial, conducted in 16 Italian centers that enrolled 281 patients between 2003 and 2008. The recruited patients were prospectively and randomly allocated to either chemotherapy alone or combined with monthly triptorelin gonadotropin-releasing hormone analog, started before chemotherapy and repeated every month throughout chemotherapy. The clinical and tumor characteristics of the patients in the control or treatment groups were similar. A total of 12 months after ending chemotherapy, the premature ovarian failure rate was 25.9% in the chemotherapy-alone group versus 8.9% in the chemotherapy and gonadotropin-releasing hormone analog group, an absolute difference of -17% (95% CI: -26 to -7.9%; p < 0.001). The odds ratio for treatment-induced premature ovarian failure was 0.28 (95% CI: 0.14-0.59; p < 0.001). The authors concluded that use of gonadotropin-releasing hormone analog chemotherapy in premenopausal breast cancer patients can significantly reduce the occurrence of chemotherapy-induced early menopause.

Toxicity of chemotherapy and radiation on female reproduction

One of the most devastating consequences of cancer treatment in the young female population is ovarian damage, resulting in diminished fertility potential. The extent of damage is related to age, chemotherapeutic regimen, and dose of pelvic radiation received. It is crucial that physicians know the impact each of these factors has on future fertility to advice patients on fertility preservation options. Anticancer drugs injure the female reproductive system through ovarian follicular and stromal damage. Although the exact mechanisms of damage remain unclear, it is essential to better understand these mechanisms to develop methods to diminish ovarian injury.

Chemotherapy-induced late transgenerational effects in mice

To our knowledge, there is no report on long-term reproductive and developmental side effects in the offspring of mothers treated with a widely used chemotherapeutic drug such as doxorubicin (DXR), and neither is there information on transmission of any detrimental effects to several filial generations. Therefore, the purpose of the present paper was to examine the long-term effects of a single intraperitoneal injection of DXR on the reproductive and behavioral performance of adult female mice and their progeny. C57BL/6 female mice (generation zero; G0) were treated with either a single intraperitoneal injection of DXR (G0-DXR) or saline (G0-CON). Data were collected on multiple reproductive parameters and behavioral analysis for anxiety, despair and depression. In addition, the reproductive capacity and health of the subsequent six generations were evaluated. G0-DXR females developed despair-like behaviors; delivery complications; decreased primordial follicle pool; and early lost of reproductive capacity. Surprisingly, the DXR-induced effects in oocytes were transmitted transgenerationally; the most striking effects being observed in G4 and G6, constituting: increased rates of neonatal death; physical malformations; chromosomal abnormalities (particularly deletions on chromosome 10); and death of mothers due to delivery complications. None of these effects were seen in control females of the same generations. Long-term effects of DXR in female mice and their offspring can be attributed to genetic alterations or cell-killing events in oocytes or, presumably, to toxicosis in non-ovarian tissues. Results from the rodent model emphasize the need for retrospective and long-term prospective studies of survivors of cancer treatment and their offspring.