Breast cancer rate after oophorectomy: A Prospective Danish Cohort Study

Risk of Fracture After Bilateral Oophorectomy

Fragility fractures, resulting from low-energy trauma, occur in approximately 1 in 10 Danish women aged 50 years or older. Bilateral oophorectomy (surgical removal of both ovaries) may increase the risk of fragility fractures due to loss of ovarian sex steroids, particularly estrogen. We investigated the association between bilateral oophorectomy and risk of fragility fracture and whether this was conditional on age at time of bilateral oophorectomy, hormone therapy (HT) use, hysterectomy, physical activity level, body mass index (BMI), or smoking. We performed a cohort study of 25,853 female nurses (≥45 years) participating in the Danish Nurse Cohort. Nurses were followed from age 50 years or entry into the cohort, whichever came last, until date of first fragility fracture, death, emigration, or end of follow-up on December 31, 2018, whichever came first. Cox regression models with age as the underlying time scale were used to estimate the association between time-varying bilateral oophorectomy (all ages, <51/≥51 years) and incident fragility fracture (any and site-specific [forearm, hip, spine, and other]). Exposure and outcome were ascertained from nationwide patient registries. During 491,626 person-years of follow-up, 6600 nurses (25.5%) with incident fragility fractures were identified, and 1938 (7.5%) nurses had a bilateral oophorectomy. The frequency of fragility fractures was 24.1% in nurses who were <51 years at time of bilateral oophorectomy and 18.1% in nurses who were ≥51 years. No statistically significant associations were observed between bilateral oophorectomy at any age and fragility fractures at any site. Neither HT use, hysterectomy, physical activity level, BMI, nor smoking altered the results. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Investigation of the female infertility risk associated with anti-cancer therapy

Female infertility is a significant health issue worldwide with a rising incidence. Anti-cancer therapy is one of the most important reasons for increasing infertility. Although anti-cancer treatment increases the rate of survival, it decreases the quality of life through its side effects. The most substantial side effects are sexual dysfunction and infertility. Breast cancer is the most common cancer. The first-line treatment of breast cancer is chemotherapy by alkylating agents like cyclophosphamide, which leads to infertility. For instance, persistent chemotherapy-induced amenorrhea among breast cancer patients could affect almost half of the patients that undergo such therapy. However, some agents or therapeutic methods can ameliorate these intoxicating effects. Chemotherapy plus gonadotropin-releasing hormone agonist, in breast cancer patients, can not only improve overall survival but also reduce ovarian toxicity. Age plays an essential role in chemotherapy-induced amenorrhea. Chemotherapy at a younger age can reduce the risk of infertility. Gynecological cancers including uterine and ovarian cancer, which have high mortality rates, are the most related cancers to infertility. Surgery is the primary treatment of gynecological cancers. Studies demonstrated that fertility-sparing surgery is a better option than radical surgery. In addition, neoadjuvant chemotherapy is mostly a better option than primary cytoreductive surgery in terms of survival and fertility. Immune checkpoint inhibitors (ICIs) have recently played a major role in treating various cancer types. However, ICIs are associated with hypophysitis, which affects ovaries and can lead to infertility. There are some options for ovarian preservation such as embryo cryopreservation, oocyte cryopreservation, ovarian transposition, ovarian tissue cryopreservation, and ovarian suppression by GnRH agonists. Anti-müllerian hormone level can be utilized to monitor the ovarian reserve. Moreover, to avoid fertility loss, approaches such as using transplantation of human placenta mesenchymal stem cells, administrating anti-inflammatory agents and hormone therapy are under investigation.

Oophorectomy and rate of dementia: a prospective cohort study

OBJECTIVE

Globally, dementia disproportionally affects women, which is not fully explained by higher female longevity. Oophorectomy at any age leads to the permanent loss of ovarian sex steroids, potentially increasing the risk of dementia. We aimed to investigate the association between oophorectomy and dementia and whether this was conditional on age at oophorectomy, hysterectomy or use of hormone therapy (HT).

METHODS

A prospective study of 24,851 female nurses from the Danish Nurse Cohort. Nurses were followed from age 60 years or entry into the cohort, whichever came last, until date of dementia, death, emigration or end of follow-up (December 31, 2018), whichever came first. Poisson regression models with log-transformed person-years as offset were used to estimate the associations.

RESULTS

During 334,420 person-years of follow-up, 1,238 (5.0%) nurses developed dementia and 1,969 (7.9%)/ 1,016 (4.1%) contributed person-time after bilateral-/unilateral oophorectomy. In adjusted analyses, an 18% higher rate of dementia was observed following bilateral oophorectomy (aRR 1.18: 95% CI, 0.89-1.56) and 13% lower rate (aRR 0.87: 95% CI, 0.59-1.23) following unilateral oophorectomy compared to nurses who retained their ovaries. Similar effects were detected after stratification according to age at oophorectomy. No statistically significant modifying effects of hysterectomy or HT were detected (Pinteraction≥0.60).

CONCLUSIONS

Bilateral, but not unilateral, oophorectomy was associated with an increased rate of incident dementia. We were unable to establish whether this association was conditional on hysterectomy or HT use. Although an increase in dementia after bilateral oophorectomy is biologically plausible, limited statistical power hampers the precision of the estimates.

The long-term association between bilateral oophorectomy and depression: a prospective cohort study

OBJECTIVE

Depression is a leading cause of disability globally and affects more women than men. Ovarian sex steroids are thought to modify depression risk in women and interventions such as bilateral oophorectomy that permanently change the sex steroid milieu may increase the risk of depression. This study aimed to investigate the associations between unilateral and bilateral oophorectomy and depression over a 25-year period (1993-2018) and whether this varied by age at oophorectomy or use of menopausal hormone therapy.

METHODS

Twenty-five thousand one hundred eighty-eight nurses aged ≥45 years from the Danish Nurse Cohort were included. Nurses with depression prior to baseline were excluded. Poisson regression models, with log-transformed person-years as offset, were used to assess the associations between oophorectomy and incident depression. Nurses who retained their ovaries were the reference group.

RESULTS

Compared with nurses with retained ovaries, bilateral oophorectomy was associated with a slightly higher rate of depression (rate ratio [RR], 1.08; 95% confidence interval [CI], 0.95-1.23), but without statistical significance. However, when stratified by age at oophorectomy, compared with nurses with retained ovaries, bilateral oophorectomy at age ≥51 years was associated with higher rates of depression (RR 1.16; 95% CI, 1.00-1.34), but not bilateral oophorectomy at age <51 years (RR 0.86; 95% CI, 0.69-1.07); P value for difference in estimates = 0.02. No association between unilateral oophorectomy and depression was observed.

CONCLUSIONS

In this cohort of Danish female nurses, bilateral oophorectomy at age ≥51 years, but not at younger ages, was associated with a slightly higher rate of depression compared with those who retained their ovaries.