Researchers from Canada have reported that women who have bilateral oophorectomy are 1.92 times as likely to develop lung cancer as women who have natural menopause. The details of this study appeared in an early on-line publication in the International Journal of Cancer on May 11, 2009.[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. Researchers affiliated with the Harvard Nurses’ Health Study have recently 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 oophorectomy.

A previous study from Japan found that either early age of menarche or early age of menopause was associated with a two-fold increased risk of developing lung cancer.[2] This study also found that women who took hormone replacement therapy for induced menopause had an even higher risk of lung cancer when compared to women with natural menopause without hormone replacement (RR=2.40).

The current Canadian study began as an evaluation of the possible association between menstruation characteristics and the development of lung cancer. The study involved 422 women with lung cancer and 577 matched controls. These researchers did not find any association between menstruation, pregnancy and lung cancer. However, they did observe that women who had bilateral oophorectomy had almost a two fold increase in risk of lung cancer compared to women who had normal menopause. They also found an inverse relationship between age at menopause and risk of lung cancer. These authors speculated that hormonal factors related to early menopause increased the risk of developing lung cancer.

Comments: These studies suggest a complex role for endogenous and exogenous estrogen in the etiology of lung cancer. 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 the risk of lung cancer and all-cause mortality. The Japanese study also suggests that hormone replacement therapy is not a good option for treating surgically induced menopause.

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