Researchers affiliated with the Harvard Nurses’ Health study have reported that women who have a hysterectomy and bilateral oophorectomy for benign disease have a lower risk of developing ovarian cancer but a higher risk of all-cause mortality, including cancer deaths, than women who have a hysterectomy without ooophorectomy. The details of this study appeared in the May 1, 2009 issue of Obstetrics and Gynecology.[1] 

For the past three decades or more, it has been a relatively common practice to perform bilateral oophorectomies in women who are undergoing a hysterectomy for benign disease. The rationale for this practice was that ovarian cancer could be prevented. However, the long-term consequences of this strategy have not been explored.

The current study analyzed data from 29,380 women; 16,345 had hysterectomy with bilateral oophorectomy and 13,035 had hysterectomy only with the ovaries left in. The follow-up of this study was 24 years. The strategy of bilateral oophorectomy reduced the risk of breast cancer by 25% and the risk of ovarian cancer by 96%. There were 34 deaths from ovarian cancer in women who had their ovaries left in. However, women who had both ovaries removed had a 12% higher mortality rate than women with ovaries left in. There was a 17% increased risk of fatal and nonfatal heart disease and a 14% increased risk for strokes in women in the oophorectomy group. There was 17% increased risk of dying of cancer of all types and a 26% increased incidence of lung cancer. There was no age group in which oophorectomy was associated with an increased survival. Women who had ovaries removed before age 50 years and did not take estrogen had the greatest risk of heart disease, stroke, and all-cause mortality when compared with women who had hysterectomy without oophorectomy. These authors speculated that women who keep their ovaries after menopause have continued production of androstenedione and testosterone, which can be converted into estrogen by fat and muscle—a process that may affect the incidence of cardiac disease. The mechanism for increased lung cancer in oophorectomized women is not explained.

Comments: This data is likely to influence major changes in recommended treatment for women who have a hysterectomy for benign disease. These data suggest that women who are not at higher than normal risk of ovarian cancer should not have bilateral oophorectomy performed for benign disease since this significantly increases all-cause mortality. However, this may still be appropriate therapy for women with BRCA gene mutations who are at high risk of ovarian cancer.

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