Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Fertility preservation, its effectiveness and its impact on disease status in pre-menopausal women with breast cancer: A systematic review and meta-analysis

INTRODUCTION

Preservation of reproductive function is a key concern for many premenopausal women with breast cancer, given the known gonadotoxic effects of treatments. The present systematic review aimed to investigate the effectiveness and safety of fertility preservation strategies in pre-menopausal women with breast cancer.

METHODS

Primary research assessing fertility preservation strategies of any type was identified. Markers of preservation of fertility including return of menstrual function, clinical pregnancy rates and live birth rates were selected as main outcome measures. An additional analysis of safety data was also performed.

RESULTS

Fertility preservation interventions were overall associated with higher fertility outcomes: with a pooled odds ratio 4.14 (95% CI 3.59-4.77) for any kind of fertility preservation intervention. This was seen both for return of menstruation and for clinical pregnancy rate, but not for live birth rates. Fertility preservation was associated with a reduced rate of disease recurrence (OR 0.63 (95% CI 0.49-0.81)), while there was no significant difference in disease free survival (OR 0.88 (95% CI 0.74-1.05)) or in overall survival (OR 0.9 (95% CI 0.74-1.10)) between the fertility preservation group and those who had not undergone fertility preservation.

CONCLUSION

Fertility preservation is both effective in preserving reproductive function, and safe with regard to disease recurrence, disease free survival and overall survival in premenopausal women with breast cancer.

Comparison of goserelin and leuprorelin for ovarian protection during chemotherapy in young patients with breast cancer

PURPOSE

Although different gonadotropin-releasing hormone (GnRH) agonists may have different effects, their effect of ovarian protection during chemotherapy for breast cancer has not been compared. This study aimed to compare the effects of goserelin and leuprorelin for ovarian protection during chemotherapy in young patients with breast cancer.

METHODS

This prospective study analyzed 193 patients with breast cancer aged ≤ 40 years who had regular menstruation and serum anti-Müllerian hormone (AMH) levels ≥ 1 ng/mL before treatment. Patients received either goserelin or leuprorelin for ovarian protection during doxorubicin/cyclophosphamide-based chemotherapy. Resumption of menstruation and changes in serum levels of AMH were compared between the two groups at 12 months after completion of chemotherapy.

RESULTS

The mean age and the pretreatment serum AMH level were 33.2 years and 4.4 ng/mL in goserelin group and 34.2 years and 4.0 ng/mL in leuprorelin group. The proportion of patients who resumed menstruation was not different between the goserelin (94.4%) and leuprorelin (95.3%) groups at 12 months after chemotherapy completion. Serum AMH levels decreased significantly in both the goserelin (from 4.4 to 1.2 ng/mL) and leuprorelin (from 4.0 to 1.2 ng/mL) groups, with no statistical significance. In addition, no difference was found in the proportion of patients with serum AMH levels ≥ 1 ng/mL between the goserelin (49.5%) and leuprorelin (44.2%) groups at 12 months after chemotherapy.

CONCLUSION

Goserelin and leuprorelin were comparable in terms of ovarian protection during doxorubicin/cyclophosphamide-based chemotherapy in young patients with breast cancer.

Fertility Preservation Using GnRH Agonists: Rationale, Possible Mechanisms, and Explanation of Controversy

The only clinically accepted method of fertility preservation in young women facing gonadotoxic chemo- and/or radiotherapy for malignant or autoimmune diseases is cryopreservation of embryos or unfertilized ova, whereas cryopreservation of ovarian tissue for future reimplantation, or in vitro maturation of follicles, and the use of gonadotropin-releasing hormone agonists (GnRHa) are still considered investigational, by several authorities. Whereas previous publications have raised the fear of GnRHa's possible detrimental effects in patients with hormone receptor-positive breast cancers, recent randomized controlled trials (RCTs) have shown that it either improves or does not affect disease-free survival (DFS) in such patients. This review summarizes the pros and cons of GnRHa co-treatment for fertility preservation, suggesting 5 theoretical mechanisms for GnRHa action: (1) simulating the prepubertal hypogonadotropic milieu, (2) direct effect on GnRH receptors, (3) decreased ovarian perfusion, (4) upregulation of an ovarian-protecting molecule such as sphingosine-1-phosphate, and (5) protecting a possible germinative stem cell. We try to explain the reasons for the discrepancy between most publications that support the use of GnRHa for fertility preservation and the minority of publications that did not support its efficiency.

Gonadotropin-Releasing Hormone Analogs for Gonadal Protection During Gonadotoxic Chemotherapy: A Systematic Review and Meta-Analysis

OBJECTIVE

A systematic review and meta-analysis was conducted to investigate whether gonadotropin-releasing hormone analogs (GnRHa) have a protective role in women treated with alkylating agents.

DATA SOURCES

Major databases (PubMED, EMBASE, Cochrane Central Register of Controlled Trials), systematic snowballing, and trial registries were screened from the inception dates until September 2017.

METHODS AND STUDY SELECTION

Comparative studies involving reproductive-aged women undergoing chemotherapy with or without coadministration of GnRHa were included. Spontaneous menstrual resumption was assessed as a main outcome. Statistical analyses were performed with STATA 14.2 statistical software. Effect estimates were presented as risk ratios (RR) with 95% confidence intervals (CIs).

RESULTS

The literature search yielded 25 436 citations and 84 papers were assessed in full text. Eighteen studies (11 randomized controlled trials [RCTs] and 7 cohort studies) published between 1987 and 2015 were included in the analysis, revealing a significant protective effect of GnRHa (n = 1043; RR:1.38; 95% CI: 1.18-1.63) although with high heterogeneity (I² = 83.3%). Subgroup analyses revealed a significant benefit of GnRHa cotreatment both in RCTs and in cohort studies. Statistical significance was found in all subgroups by the underlying disease, that is, hematological malignancies, autoimmune diseases, and breast cancer. Sensitivity analyses in GnRH agonist-treated patients, in patients younger than 40 years old, and in patients without supradiaphragmatic radiotherapy also revealed a significant benefit of GnRHa cotreatment.

CONCLUSION

Our results indicate that concurrent GnRHa administration is an effective method to decrease gonadotoxicity of alkylating agents. The presence of low-quality evidence favoring gonadoprotective effect requires a strong recommendation for offering GnRHa coadministration to young women who are to undergo gonadotoxic chemotherapy.

CAPSULE

The present systematic review and meta-analysis shows a significant gonadoprotective effect of gonadotropin-releasing hormone analogs in women treated with alkylating agents.

Utility of gonadotropin-releasing hormone agonists for prevention of chemotherapy-induced ovarian damage in premenopausal women with breast cancer: a systematic review and meta-analysis

Background

Premature ovarian failure and infertility following chemotherapy are major concerns for premenopausal women with breast cancer. A potential ovarian function preservation strategy is administration of gonadotropin-releasing hormone (GnRH) agonists during adjuvant chemotherapy; however, studies of the clinical efficacy of GnRH agonists to protect chemotherapy-induced ovarian damage have shown mixed results.

Objective

This meta-analysis study was designed to estimate the efficacy of GnRH agonists administered concurrently with chemotherapy to prevent chemotherapy-induced ovarian damage in premenopausal women with breast cancer.

Methods

Electronic literature databases (PubMed, EMBASE, MEDLINE, Cochrane Library databases searching, China National Knowledge Infrastructure, Web of Science, and the Wanfang Data) were searched for relevant randomized controlled trials (RCTs) published until September 2015. Only RCTs that examined the effect of GnRH agonists for chemotherapy-induced ovarian failure in premenopausal women with breast cancer were selected. The rate of spontaneous resumption of menses and spontaneous pregnancy were collected. All data were analyzed by RevMan 5.3 (Cochrane Collaboration, Copenhagen, Denmark) and Stata 12.0 (StataCorp, College Station, TX, USA).

Results

Eleven RCTs with a total of 1,062 participants (GnRH agonists administered concurrently with chemotherapy, n=541; chemotherapy alone, n=521) were included in the meta-analysis. A significantly greater number of women treated with GnRH agonist experienced spontaneous resumption of menses after the adjuvant chemotherapy, yielding a pooled odds ratio of 2.57 (versus chemotherapy alone, 95% confidence interval (CI)=1.65, 4.01; P<0.0001). A subgroup analysis showed that addition of GnRH agonists significantly improved the resumption of menses rate in patients who were hormone-insensitive. However, the two treatment groups experienced similar spontaneous pregnancy (odds ratio =0.177; 95% CI=0.92, 1.40; P=0.09).

Conclusion

GnRH agonists cotreatment with chemotherapy in premenopausal women with breast cancer plays a beneficial role in resumption of ovarian function, with a higher rate of resumption of menses. However, treatment with GnRH agonists does not appear to exhibit its protective effects in fertility.

Gonadotropin-releasing hormone agonists for the preservation of ovarian function among women with breast cancer who did not use tamoxifen after chemotherapy: a systematic review and meta-analysis

OBJECTIVE

To determine whether concurrent use of GnRH agonists with chemotherapy preserves ovarian function in women with breast cancer who did not use tamoxifen.

DESIGN

Systematic review and meta-analysis.

SETTING

University-based hospitals.

PATIENT(S)

Premenopausal women with breast cancer treated with chemotherapy who did not receive tamoxifen.

INTERVENTION(S)

Randomization to concurrent GnRH agonists with chemotherapy or chemotherapy alone.

MAIN OUTCOME MEASURE(S)

Odds ratio (OR) of resumption of menses 1 year or more after chemotherapy.

RESULT(S)

Searches were conducted in PubMed, Scopus, Cochrane Trials Register, and the National Research Register through March 2014, and all randomized trials that reported resumption of menses 1 year or more after GnRH agonist with chemotherapy or chemotherapy alone among women with breast cancer who did not receive tamoxifen were included. Four studies were analyzed in the meta-analysis and included 252 patients (GnRH agonist with chemotherapy, n=131; chemotherapy alone, n=121). There was no significant difference in the rate of return of menses between the two groups (OR, 1.47; 95% confidence interval [0.60-3.62]). Heterogeneity among the trials was not significant (I2=16.6%).

CONCLUSION(S)

Concurrent GnRH agonists with chemotherapy may not preserve ovarian function in women with breast cancer. Furthermore, randomized data are limited regarding fertility after concurrent use of GnRH agonists with chemotherapy.

Fertility preservation in women undergoing treatment for breast cancer in the UK: a questionnaire study

OBJECTIVE

Fertility preservation is an important survivorship issue for women treated for breast cancer. The aim of this work was to examine the referral practices of health care professionals who treat women with breast cancer in the United Kingdom, and to investigate their understanding and knowledge of the fertility preservation options available.

METHOD

An invitation to participate in a confidential, online questionnaire was e-mailed to surgeons, oncologists, and clinical nurse specialists who manage patients with breast cancer in the United Kingdom.

RESULTS

n = 306 respondents. Factors which influenced whether fertility preservation options were discussed with a patient included the following: patient's age (78%), final tumor/nodes/metastasis status (37.9%); concern that fertility preservation would delay chemotherapy (37.3%); whether the patient had children (33.5%) or a partner (24.7%); estrogen receptor expression (22.6%), lack of knowledge regarding the available options (20.9%); and concern that fertility preservation would compromise the success of cancer treatment (19.8%). Twenty-seven percent did not know whether fertility preservation was available for their patients on the National Health Service. Nearly half (49.4%) of respondents said that gonadotropin-releasing hormone agonists were used for fertility preservation outside the setting of a clinical trial. Knowledge regarding the available options varied according to different members of the multidisciplinary team, with consultant oncologists better informed than consultant surgeons or clinical nurse specialists (p < .05).

CONCLUSIONS

Many health care professionals have incomplete knowledge regarding the local arrangements for fertility preservation for patients with breast cancer. This may result in patients receiving inadequate or conflicting information regarding fertility preservation.