Risk of breast cancer in women treated with ovarian stimulation drugs for infertility: a systematic review and meta-analysis

An umbrella review of meta-analyses regarding the incidence of female-specific malignancies after fertility treatment

IMPORTANCE

Understanding the potential risks associated with fertility treatments (FTs) can guide clinical decision and patient counseling.

OBJECTIVE

To investigate the validity of the association between the development of female-specific malignancies including ovarian, endometrial, breast, and cervical cancer after FT.

DATA SOURCES

A search of systematic reviews and meta-analyses was performed from inception to April 2022 within several databases: Cochrane Database of Systematic Reviews, EMBASE, Google Scholar, and PubMed.

STUDY SELECTION AND SYNTHESIS

The inclusion criteria required the incidence of each cancer subgroup to be stated in both the defined treatment group (controlled ovarian stimulation and/or in vitro fertilization [IVF] or intracytoplasmic sperm injection) and the control group (no-FT, general population). From 3,129 identified publications, 11 meta-analytical reviews consisting of 188 studies were selected for synthesis.

MAIN OUTCOME

The primary outcome of interest was incidence of each subgroup of cancer in the "FT" group compared with the "no-FT" group.

RESULTS

A statistically significant increase in incidence of ovarian (1,229/430,611 in FT group vs. 27,358/4,263,300 in no-FT group) cancer (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.00-1.45) and borderline ovarian tumors (117/414,729 in FT group vs. 934/2,626,324 in no-FT group) (OR, 1.87; 95% CI, 1.18-2.97) was observed. The incidence of ovarian cancer was higher with FT and IVF specifically (OR, 1.65; 95% CI, 1.07-2.54). For borderline ovarian tumors, the incidence was higher, not only with FT overall and IVF, but also according to the fertility drug regimen applied: clomiphene citrate (CC) only (OR, 1.99; 95% CI, 1.02-3.87), human menopausal gonadotropin only (OR, 3.46; 95% CI, 1.39-8.59), and CC and human menopausal gonadotropin combined (OR, 3.79; 95% CI, 1.47-9.77). When using the threshold for statistical significance, the meta-analyses relevant to ovarian cancers remained statistically significant (random-effects method). However, none of the examined associations could claim either strong or highly suggestive evidence.

CONCLUSION AND RELEVANCE

An observed association between ovarian cancer (including borderline ovarian tumors) and FT has been demonstrated. The association between FT and female-specific malignancy remains a contentious topic because there have been contradictory outcomes among meta-analyses. This umbrella review interrogates existing systematic reviews and meta-analyses on this topic and concludes that a statistically significant increase in the incidence of ovarian cancer and borderline ovarian tumors is associated with FT. These findings have a significant clinical impact because it helps to inform and provide effective counseling for patients undergoing FT.

Estrogens and breast cancer

Estrogens have been associated with an increase in breast cancer risk. Yet emerging clinical and experimental evidence points to progestogens [endogenous progesterone or synthetic progesterone (progestin)] as the primary hormonal driver underlying seemingly estrogen-associated breast cancer risk. Estrogens may contribute to breast cancer risk indirectly by induction of the progesterone receptor and thus amplifying progesterone signaling. Large studies of hormonal contraceptives suggest that the small increase in breast cancer risk from hormonal contraceptives is mainly attributable to progestins, not estrogens. Estrogen-plus-progestin hormone replacement therapy (HRT) has consistently shown an increase in breast cancer risk among postmenopausal women, whereas estrogen-alone HRT has little impact on breast cancer risk in naturally or surgically menopausal women. In particular, the long-term follow-up of the Women's Health Initiative (WHI) randomized trials suggests a benefit of estrogen alone. Recent data further indicate that endogenously elevated estrogen during assisted reproductive technology (ART) exhibits little adverse effect on or potentially a reduction in breast cancer risk and recurrence. Also, accumulating evidence suggests that inhibition of progesterone signaling is a critical mechanism underlying the risk-reducing and therapeutic effects of antiestrogens. Estrogen HRT has shown an array of proven benefits, including ameliorating menopausal symptoms and improving bone health. Collective evidence thus suggests that estrogen HRT is likely to offer health benefits to perimenopausal or postmenopausal women, including breast cancer survivors, as well as young BRCA1/2 carriers with prophylactic oophorectomy for ovarian cancer prevention.

Investigation of the relationship between breast cancer and clinical symptoms of polycystic ovarian syndrome: a case-control study

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among women worldwide, and it is associated with significant number of metabolic and reproductive risk factors. Despite the overlap between hormonal and metabolic factors involved in the development of PCOS and many known risk factors for breast cancer, the relationship between PCOS and breast cancer, the most common type of cancer among women, remains unknown. This study was conducted with the aim of determining the relationship between breast cancer and clinical symptoms of PCOS.

METHODS

This case-control study was conducted on 285 women with breast cancer and 285 healthy women referred to three centers in Tehran in 2023. Both the case and control groups were matched in terms of age and body mass index. The data collection tool in this study was a researcher-made data registration form, that was completed in person by qualified individuals. A history of PCOS was identified according to the Rotterdam criteria. Women aged 15-49 years who were able to read and write were included in the study. The case group had a history of breast cancer, while the control group did not. Participants who did not consent to having their data use in the analysis were excluded. Data was analyzed using an independent t-test, a chi-square test and a logistic regression model.

RESULTS

The mean age of the participants in the case group was 43.05 ± 4.92 years and that of the control group was 42.78 ± 5.06 years. The two groups showed a statistically significant difference in terms of PCOS history (p < 0.001). After adjusting for confounding variables, the logistic regression model showed that women with PCOS had a significantly higher chance of developing breast cancer (0R: 3.677, 95%CI: 1.529-8.840, P = 0.004). Among PCOS symptoms, women with a history of hirsutism had a higher chance of developing breast cancer (OR: 2.188, 95% CI: 1.014-4.720, P = 0.046).

CONCLUSION

The findings of the present study suggest that PCOS is a risk factor for breast cancer. Well-designed further studies are highly recommended to determine the role of PCOS in predicting breast cancer.

Infertility treatments and risk of breast benign diseases: a case‒control study

BACKGROUND

Theoretically, endocrine fluctuations occurring during infertility treatments, including ovulation induction (OI) and assisted reproductive techniques (ART), could be associated with an increased risk of benign breast diseases (BBDs). To date, no studies have been conducted on this association. Therefore, the present study investigated the association between different types of infertility treatments and BBDs.

METHODS

This case‒control study was conducted in Arash Women's Hospital, Tehran, Iran. The case group included infertile women diagnosed with BBDs without atypia, and the control group included infertile women without breast disease. Breast imaging studies (mammography/ultrasound) were performed for BBD screening, and the diagnosis was confirmed by histopathological examination. Study variables were collected retrospectively from medical records, hospital databases, and questionnaires.

RESULTS

Finally, 154 infertile women, including 50 cases (BBDs) and 104 controls (no BBDs), were compared. Our data showed that 66% of cases and 61.4% of controls had undergone at least one course of infertility treatment. There was no association between BBD risk and previous infertility treatments (OR = 1.21; 95% CI = 0.59-2.46), ART (OR = 1.14; 95% CI = 0.90-1.44), or OI cycles (OR = 1.13; 95% CI = 0.98-1.32). Stratification by confounding variables did not change these results.

CONCLUSIONS

It seems that there is no association between BBDs in infertile women and the type, duration, or number of prior infertility treatments; however, considering the small sample size of the study, the clinical significance of this finding should not be neglected. Therefore, we consider it essential to carry out more extensive, detailed, and prospective studies to distinguish the association of BBDs with different infertility treatments and medications.

Patient experience of social and medical fertility preservation fully reimbursed in France

PURPOSE

The purpose of this study is to review patient experience with social fertility preservation (sFP), as compared to medical fertility preservation (mFP), in a context where sFP is fully reimbursed.

METHODS

We conducted a retrospective cohort study involving patients who underwent oocyte cryopreservation for mFP between 2017 and 2023 and sFP between 2022 and 2023 at a large ART single center. Additionally, we surveyed patients undergoing sFP and mFP, regarding their experiences, intentions, awareness, and financial consideration.

RESULTS

A total of 97 oocyte retrievals were performed for sFP in 75 women, and 155 were performed in mFP (127 women). Median ages were 36.4 years for sFP and 28.9 years for mFP. Median oocytes retrieved per session were 10 for sFP and 8 for mFP. Ninety-seven percent of of mFP participants were informed by healthcare professionals, while half of sFP participants learned through personal acquaintances. The primary motivation for sFP was a desire for pregnancy while being single. Most respondents in both groups knew that 15-20 oocytes are typically needed for a successful birth. None were aware of the "DuoStim" option, but interest was expressed by most women. Surprisingly, despite full reimbursement for sFP in France, 78% expressed willingness to pay if necessary.

CONCLUSION

Many women choose sFP due to concerns about declining fertility, often informed by non-medical sources. Free access to sFP can help mitigate the global decline in natality by allowing women to anticipate age-related fertility decline. This study should be considered by other countries as they may increasingly cover sFP costs in the future.

Cancer-Related Morbidity Among Patients Conceiving Through Oocyte Donation: A Healthcare Registry Cohort Study

Background: Ovarian aging, often leads to increased use of a donor oocyte, which is associated with greater risk for age-related diseases. Objective: To evaluate the association between women conceiving through oocyte donation (OD) and future cancer-related morbidity, as compared with women conceiving through IVF (in vitro fertilization) with autologous oocytes (AO), spontaneous conceptions (SC), and nulliparas. Methods: This retrospective, cohort study was based on the electronic health records of a very large health maintenance organization. The cohort included mothers who delivered before age 45, during 2000-2019. The index date for surveillance was the delivery date of the relevant pregnancy. Each woman from the OD group was matched to a woman the same age at delivery and with the same number of children. Cancer diagnosis was the main outcome. Results: Matching: 664 OD cases to 664 AO, 700 OD cases to 700 SC, and 700 OD cases to 700 nulliparas. Mean follow-up times were 8.9 ± 3.8 OD, 10 ± 4.1 AO, and 6.4 ± 4.1 years SC. Cancer-related morbidity rates were comparable between OD and the other groups, but compared with nulliparas, a trend was noted (1.6% and 3.1%, respectively, p = 0.07). Survival analysis curves were not significantly different, although a trend was shown in the curve comparing to nulliparity (p = 0.07). In a Cox regression model corrected for BMI, smoking and hormone replacement therapy exposure, cancer in the OD group did not differ compared to the other groups. Conclusion: Women conceiving through OD do not have increased risk for cancer-related morbidity in the decade following delivery.

Impact of repeated ovarian hyperstimulation on the reproductive function

One of six couples (17.5 % of the adult population) worldwide is affected by infertility during their lifetime. This number represents a substantial increase in the prevalence of this gynecological condition over the last decade. Ovulatory dysfunction and anovulation are the main causes of female infertility. Timed intercourse, intrauterine insemination, and assisted reproductive technology (ART), such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), are the most common interventions for infertile couples. Ovulation induction protocols for IVF/ICSI routinely use supraphysiological doses of gonadotropins to stimulate many preovulatory follicles. Animal and human studies suggested that ovarian hyperstimulation, alone or repeatedly, for ART cycles can induce changes in the immune response and increase the oxidative stress (OS) in the ovarian microenvironment. The consequences of repeated ovarian hyperstimulation on the human ovary remain poorly understood, particularly in relation to the effects of ovarian stimulation on the immune system and the potential for ovarian stimulation to cause OS. Animal studies have observed that repeated cycles of ovarian hyperstimulation can accelerate ovarian aging. Changes in ovarian hormone levels, accelerated loss of ovarian reserve, disorders in ovarian ultrastructure, ovarian senescence, and decreased reproductive performance represent possible long-term effects of repeated ovarian hyperstimulation. The short and long-term impact of the combination of antioxidant agents in ovarian hyperstimulation protocols in women undergoing ART must urgently be better understood. The recent increase in the number of ART and fertility preservation cycles may accelerate ovarian aging in these women, promoting consequences beyond the reproductive function and including health deterioration.

Estimating the impact of bias in causal epidemiological studies: the case of health outcomes following assisted reproduction

Researchers interested in causal questions must deal with two sources of error: random error (random deviation from the true mean value of a distribution), and bias (systematic deviance from the true mean value due to extraneous factors). For some causal questions, randomization is not feasible, and observational studies are necessary. Bias poses a substantial threat to the validity of observational research and can have important consequences for health policy developed from the findings. The current piece describes bias and its sources, outlines proposed methods to estimate its impacts in an observational study, and demonstrates how these methods may be used to inform debate on the causal relationship between medically assisted reproduction (MAR) and health outcomes, using cancer as an example. In doing so, we aim to enlighten researchers who work with observational data, especially regarding the health effects of MAR and infertility, on the pitfalls of bias, and how to address them. We hope that, in combination with the provided example, we can convince readers that estimating the impact of bias in causal epidemiologic research is not only important but necessary to inform the development of robust health policy and clinical practice recommendations.

Predisposing and Overall Effects of Reproductive Hormones on Breast Cancer: A Review

Cancer, the second leading cause of mortality worldwide, has been the subject of extensive and quickly changing scientific study and practice. Cancer remains a mystery despite the enormous effort put into understanding the genesis of cancerous cells, the development of malignant tissues, and the process by which they propagate and recur. Cells from humans that have been recruited by cancer and, to some extent, changed into pathogenic organisms or the foundation of tumors serve as agents of destruction. Understanding cancers leads to challenging philosophical issues since they undermine and use multicellular organization processes. Cancer metastasizing cells adopt new phenotypes while discarding previous behaviors. The absence of comprehensive knowledge of this has hampered the development of therapeutics for metastatic illness. For systems-level experimental and computational metastasis modeling, integrating these complex and interconnected features continues to be a problem because metastasis has typically been studied in separate physiological compartments. Lung, breast, and prostate cancers accounted for the bulk of the 18 million new cases of cancer that were diagnosed in 2018. The most frequent cancer in women is breast cancer. Animal experimentation plays a significant role in primary and translational breast cancer research. In theory, such breast cancer models should be comparable to breast cancer in humans in terms of tumor etiology, biological behavior, pathology, and treatment response.

History of infertility and risk of breast cancer: a prospective cohort study

PURPOSE

Research on infertility and risk of breast cancer has been conflicting, potentially because many well-established breast cancer risk factors, such as pregnancy history, are strongly correlated with infertility.

METHODS

We followed participants in the Nurses' Health Study II from 1989 to 2015 (n = 103,080) for the development of invasive breast cancer and calculated Hazard Ratios (HR) and 95% confidence intervals (CI) using Cox regression. Participants with a self-reported history of infertility (12 months of trying without conception) were compared to gravid women with no history of infertility. We classified breast cancer by menopausal status and investigated mediation by reproductive factors.

RESULTS

Over 26 years of follow-up, 26,208 (25.4%) women reported a history of infertility, and 3,201 women were newly diagnosed with invasive breast cancer. We observed no association between infertility history and risk of overall breast cancer (HR: 1.05, 95% CI: 0.97-1.14) or premenopausal breast cancer (RR: 0.93, 95% CI: 0.83-1.03). However, we observed a modest association between history of infertility and risk of postmenopausal breast cancer (HR: 1.13, 95% CI: 1.00-1.28), approximately 50% of which could be attributed to lower total parity and later age at first birth (95% CI: 8.2%-91.0%).

CONCLUSIONS

Women with a history of infertility were at increased risk of postmenopausal breast cancer. Older age at first birth and lower total parity explained approximately half of the association between infertility and risk of postmenopausal breast cancer.

Routine double-ovarian-stimulation (DuoStim) in poor responders lacks rationale, evidence, and follow-up

Double ovarian stimulation (DuoStim), initially only suggested for fertility preservation in cancer patients, is now increasingly also used in routine clinical IVF, especially in poor responders. The claimed rational for this is the alleged existence of multiple follicular waves in a single intermenstrual interval, allowing for retrieval of more oocytes in a single IVF cycle. This commentary argues that this expansion of purpose lacks rationale, evidence, and follow-up. Consequently, we suggest that, unless valid clinical indications have been established, DuoStim be only subject of controlled clinical trials with appropriate experimental consents.

Contribution of genetic factors in the occurrence of breast cancer in cuban women

Introduction: breast cancer is a disease of multifactorial etiology, where genetic factors and environmental factors are involved, in Cuba it constitutes the second cause of mortality in women "however" it is not known what the risk of a woman is developing it attributable to genetic predisposition, limiting an effective genetic counseling. Objective: to identify the preferential clustering of breast cancer in relatives of cases with respect to the population and to analyze the genetic contribution in people with breast cancer attended at the National Institute of Oncology and Radiobiology (INOR). Methods: we conducted an analytical study of cases and nested neighborhood controls in a dynamic cohort. The sample consisted of 66 cases and 132 controls. The genetic contribution was studied through the tools of genetic epidemiology. Results: there was a preferential clustering of this disease in families that, in the population, genetic factors defined the familial prevalence of breast cancer in the relatives of the cases and there was an increasing tendency to suffer the disease as the proportion of genes to be shared increases. Conclusion: the preferential aggregation of breast cancer is identified and the contribution of genetic factors in the appearance of this disease in women attended at INOR is analyzed, showing that a person has three times more risk of suffering breast cancer attributable to the history of this disease in second-degree relatives

Fertility Treatments and Breast Cancer: A Significant Risk for Our Patients?

Fertility medications have been postulated to increase the risk of breast cancer because of the transient but substantial elevation in hormones occurring with their use. Multiple studies exploring the relationship between fertility medications and risk of breast cancer are limited by the wide variety of fertility treatment regimens and confounded by infertility as an independent risk factor for breast cancer. The Practice Committee Guidelines of the American Society of Reproductive Medicine acknowledge that although this relationship is complex, no additional risk of breast cancer has been consistently linked to infertility medications. This article reviews the major studies both supporting and refuting this statement and makes recommendations regarding risk counseling and breast cancer screening in patients with a history of fertility treatments and infertility.

Efficacy of digital breast tomosynthesis combined with magnetic resonance imaging in the diagnosis of early breast cancer

BACKGROUND

The incidence and mortality rate of breast cancer in China rank 120^th and 163^rd, worldwide, respectively. The incidence of breast cancer is on the rise; the risk increases with age but is slightly reduced after menopause. Early screening, diagnosis, and timely determination of the best treatment plan can ensure clinical efficacy and prognosis.

AIM

To evaluate the clinical value of magnetic resonance imaging (MRI) combined with digital breast tomosynthesis (DBT) in diagnosing early breast cancer and the effect of breast-conserving surgery by arc incision.

METHODS

This study was divided into two parts. Firstly, 110 patients with early breast cancer confirmed by pathological examination and 110 with benign breast diseases diagnosed simultaneously in Changzhi People’s Hospital of Shanxi Province and Shanxi Dayi Hospital from May 2019 to September 2020 were included in the breast cancer group and the benign group, respectively. Both groups underwent DBT and MRI examination, and the pathological results were used as the gold standard to evaluate the effectiveness of the combined application of DBT and MRI in the diagnosis of early breast cancer. Secondly, according to the operation method, 110 patients with breast cancer were divided into either a breast-conserving group (69 patients) or a modified radical mastectomy group (41 patients). The surgical effect, cosmetic effect, and quality of life of the two groups were compared.

RESULTS

Among the 110 cases of breast cancer, 66 were of invasive ductal carcinoma (60.00%), and 22 were of ductal carcinoma in situ (20.00%). Among the 110 cases of benign breast tumors, 55 were of breast fibromas (50.00%), and 27 were of breast adenosis (24.55%). The sensitivity, specificity, and area under the curve (AUC) of DBT in the differential diagnosis of benign and malignant breast tumors were 73.64%, 84.55%, and 0.791, respectively. The sensitivity, specificity, and AUC of MRI in the differential diagnosis of benign and malignant breast tumors were 84.55%, 85.45%, and 0.850, respectively. The sensitivity, specificity, and AUC of DBT combined with MRI in the differential diagnosis of benign and malignant breast tumors were 97.27%, 93.64%, and 0.955, respectively. The blood loss, operation time and hospitalization time of the breast-conserving group were significantly lower than those of the modified radical treatment group, and the difference was statistically significant (P < 0.05). After 3 mo of observation, the breast cosmetic effect of the breast-conserving group was better than that of the modified radical group, and the difference was statistically significant (P < 0.05). Before surgery, the quality-of-life scores of the breast-conserving and modified radical mastectomy groups did not differ (P > 0.05). Three months after surgery, the quality-of-life scores in both groups were higher than those before surgery (P < 0.05), and the quality-of-life score of the breast-conserving group was higher than that of the modified radical group (P < 0.05). In the observation of tumor recurrence rate two years after the operation, four patients in the breast-conserving group and one in the modified radical treatment group had a postoperative recurrence. There was no significant difference in the recurrence rate between the two groups (χ² = 0.668, P = 0.414 > 0.05).

CONCLUSION

MRI combined with DBT in diagnosing early breast cancer can significantly improve the diagnostic efficacy compared with the two alone. Breast-conserving surgery leads to better cosmetic breast effects and reduces the impact of surgery on postoperative quality of life.

Association between fertility treatments and breast cancer risk in women with a family history or BRCA mutations: a systematic review and meta-analysis

Women with hereditary breast cancer factors are more likely to be infertile and tend to receive fertility treatments. The safety of fertility treatments that contain hormone-related medications for ovarian stimulation has gained wide attention; however, evidence of the safety of fertility treatments is limited. This study aims to assess the association between fertility treatments and the incidence rate of breast cancer in women with a family history of breast cancer or BRCA mutations. A literature search was conducted in PubMed, Cochrane Library, and Embase. Studies concerning the effect of fertility treatments on breast cancer risk in genetically susceptible women were included. The fixed and random effects models were used to estimate the summary effects. Risk Of Bias In Non-randomized Studies - of Interventions instrument was used to assess the risk of bias in the included studies. A total of 5,282 studies were screened. Five cohort studies and three case-control studies were included. Breast cancer risk was not significantly increased by fertility treatments in general genetically susceptible women [pooled odds ratio (OR) 1.18, 95% confidence interval (CI) 0.96-1.45], women with a family history of breast cancer (pooled OR 1.35, 95% CI 0.97-1.89), or women with BRCA mutations (pooled OR 1.02, 95% CI 0.74-1.4). In subgroup analyses, there was no significant increase in breast cancer risk whether in BRCA1 mutation carriers (pooled OR 1.18, 95% CI 0.81-1.72), BRCA2 mutation carriers (pooled OR 0.54, 95% CI 0.09-3.34), or in the women treated with in vitro fertilization (pooled OR 0.75, 95% CI 0.51-1.1), clomiphene citrate (pooled OR 1.07, 95% CI 0.78-1.45) or gonadotropins (pooled OR 1.32, 95% CI 0.8-2.18). This is the first meta-analysis concerning the impact of fertility treatments on breast cancer risk in genetically susceptible women. Despite the finding that fertility treatment did not significantly increase breast cancer risk in genetically susceptible women, large prospective cohorts with more detailed information are required. Further investigations are needed to explore subtypes of breast cancer, genetic background of hormone-related breast cancer, and the association between BRCA mutations and the incidence of hormone receptor-positive breast cancer.

REGISTRATION NUMBER

PROSPERO(CRD42021281336).

Current Resources for Evidence-Based Practice, November 2021

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of autonomy and respect in maternity care and commentaries on reviews focused on whether to induce women who present with mild preeclampsia in the late preterm period and the extent to which urinary incontinence symptoms prevent women from participating in exercise. It also includes a brief update about the USPSTF guidelines on screening for gestational diabetes.