Dr. Vanessa Jacoby and team collected data from the WHI (Women's Health Initiative), which included over 25,000 postmenopausal females aged between 50 and 70 - all of them had undergone a hysterectomy and none of them had a family history of ovarian cancer. Approximately 56% of them also had their ovaries removed. 79% had received some form of HRT (hormone replacement therapy). The women were followed-up for an average of 7 to 8 years to find out how many developed heart disease, hip fracture or ovarian cancer.
They found that ovarian cancer developed in 1 in every 300 women who just had a hysterectomy, compared to 1 in 5,000 who had their ovaries removed too.
Both groups of women - those with just hysterectomies and those with hysterectomies plus ovary removal had similar hip fracture and heart disease rates - 8 in every 1,000 annually.
A hysterectomy is the surgical removal of the uterus - sometimes it may include the cervix. When both the uterus and the cervix are removed, the procedure is called a total hysterectomy. Removing just the body of the uterus without removing the cervix is known as a subtotal hysterectomy. An oophorectomy or ovariectomy is the surgical removal of one or both ovaries.
Their findings went against the Nurses' Health Study, which appeared to find an association between oophorectomy and a higher risk of cancer deaths, heart disease and mortality in general.
Although the Nurses' Health Study was also large and had a longer follow-up period, it only covered women aged between 51 and 63 years.
Dr. Vanessa Jacoby said:
"What our study emphasizes is that it's very unclear because there's this equivocal mix of data. There's really no right answer about what to do about removing or retaining your ovaries during a hysterectomy. Definitely a lot more work needs to be done."
In the USA, approximately 600,000 hysterectomies are carried out annually. They are commonly performed on women who have not yet reached the menopause but have heavy bleeding or bothersome benign tumors growing in the uterus. Patients aged at least 40 years are usually offered oophorectomy too, to protect from ovarian cancer. Ovarian cancer only affects about 1.4% of females, however, it has a very high death rate.
When HRT became less popular for the treatment of menopausal symptoms, removing ovaries from females with no family history of ovarian cancer became a controversial subject. HRT was linked to a higher risk of stroke, heart disease and cancer in the Women's Health Initiative trial.
Jacoby stressed that their study had nothing to do with hormone therapy usage.
The researchers said that their finding suggest that performing an oophorectomy does not increase a woman's risk of developing certain diseases and conditions.
Postmenopausal women who have their ovaries removed do not have significantly different hormone levels compared to those who keep their ovaries - the hormone level difference is not enough to have an impact on their long-term health, the authors explain.
The authors added that women who undergo a hysterectomy and keep their ovaries have lower ovarian cancer risk than females who never have a hysterectomy.
Although the women in this latest study who had their ovaries removed had no higher risk of developing stroke, heart attack or pulmonary blood clots, they did have a moderately higher risk of subsequent hypertension (high blood pressure) and angina.
"Oophorectomy vs Ovarian Conservation With Hysterectomy - Cardiovascular Disease, Hip Fracture, and Cancer in the Women's Health Initiative Observational Study"
Vanessa L. Jacoby, MD, MAS; Deborah Grady, MD, MPH; Jean Wactawski-Wende, PhD; JoAnn E. Manson, MD, DrPH; Matthew A. Allison, MD, MPH; Miriam Kuppermann, PhD, MPH; Gloria E. Sarto, MD, PhD; John Robbins, MD, MSH; Lawrence Phillips, MD; Lisa W. Martin, MD; Mary Jo O'Sullivan, MD; Rebecca Jackson, MD; Rebecca J. Rodabough, MS; Marcia L. Stefanick, PhD
Arch Intern Med. 2011;171(8):760-768. doi:10.1001/archinternmed.2011.121
Written by Christian Nordqvist