Ovary removal linked to increased mortality for some women
When a woman is recommended to undergo a hysterectomy, the question arises regarding whether to remove the ovaries at the time of surgery even if they are normal. A benefit of the procedure, known as a bilateral oophorectomy, is that it removes the risk of ovarian cancer. However, according to a new study, there is a downside to a bilateral oophorectomy.
Researchers affiliated with the University of Southern California, Stanford University, Harvard medical School, and the University of Auckland published their findings in the April 2013 edition of the journal Obstetrics & Gynecology. The researchers note that each year approximately 610,000 U.S. women undergo a hysterectomy for benign diseases such as fibroid tumors or bleeding problems; 23% of women aged 40–44 years and 45% of women aged 45–49 years undergo an elective bilateral oophorectomy to prevent the subsequent development of ovarian cancer. Bilateral oophorectomy, when compared with ovarian conservation, is associated with a decreased risk of ovarian cancer; however, it may increase risks of death from coronary heart disease and all causes. The investigators note that some studies report inconsistent findings in regard to this issue; however, they include small numbers of women, have short-term or delayed onset of follow-up, or compared oophorectomy with natural menopause.
To clarify the issue, the researchers accessed data from the Nurses’ Health Study, which is a large, ongoing prospective (forward-looking) observational study of women and health outcomes. In a previous investigation comprised of 24 years of follow-up, the researchers found that bilateral oophorectomy, compared with ovarian conservation, at the time of hysterectomy was associated with a lower risk of ovarian and breast cancer but a higher risk of coronary heart disease, stroke, lung cancer, and total cancers, as well as mortality from all causes. They explain that in this further analysis of updated data from the Nurses’ Health Study, they focused on all-cause and cause-specific mortality and addressed clinical issues raised by earlier publications. Specifically, they examined bilateral oophorectomy compared with ovarian conservation in women aged 60 years or older and determined whether there was an age at which oophorectomy confers a survival benefit. They also conducted analyses in several subgroups of women who they hypothesized would experience a more elevated mortality after bilateral oophorectomy, including women who underwent hysterectomy before age 50 years who never used estrogen therapy; women with known risk factors for cardiovascular disease; women with a family history of breast or ovarian cancer; and women who smoked. Finally, they examined cardiovascular disease mortality associated with oophorectomy status in women who were observed for 15 years or longer after hysterectomy to ascertain whether long-term follow-up is important for this research.
The study group comprised 30,117 Nurses’ Health Study participants undergoing hysterectomy for benign disease. They used a statistical analysis method known as multivariable adjusted hazard ratios for death from coronary heart disease, stroke, breast cancer, epithelial ovarian cancer, lung cancer, colorectal cancer, total cancer, and all causes. They compared bilateral oophorectomy (16,914 women) with ovarian conservation (13,203 women).
The researchers found that after more than 28 years of follow-up, 16.8% of women with hysterectomy and bilateral oophorectomy died from all causes compared with 13.3% of women who had ovarian conservation (1.13-fold increased risk). Oophorectomy was associated with a lower risk of death from ovarian cancer (four women with oophorectomy compared with 44 women with ovarian conservation) and, before age 47.5 years, a lower risk of death from breast cancer. However, at no age was oophorectomy associated with a lower risk of other cause-specific or all-cause mortality. For women younger than 50 years at the time of hysterectomy, bilateral oophorectomy was associated with significantly increased mortality in women who had never used estrogen therapy but not in past and current users.
The authors concluded that bilateral oophorectomy is associated with increased mortality in women aged younger than 50 years who never used estrogen therapy and at no age is oophorectomy associated with increased survival.
Take home message:
This study notes an increased mortality rate for women who do not receive hormonal replacement therapy (HRT) following a bilateral oophorectomy. Instituting HRT after the surgery poses a slight increased risk of breast cancer; however, it reduces the risk of cardiovascular disease. Women with a family history of ovarian cancer or those who carry the BRCA1 or BRCA2 gene should definitely consider an oophorectomy. The safest form of HRT currently is the low dose estrogen patch. Any woman who is faced with a hysterectomy should thoroughly discuss her individual situation with her gynecologist.
Reference: Obstetrics & Gynecology