How much can oophorectomy reduce the risk of cancer?

If you have a BRCA mutation, a prophylactic oophorectomy can reduce your:

• Breast cancer risk by up to 50 percent in premenopausal women. As an example, if a woman with a high risk of breast cancer had a 60 percent chance of being diagnosed with breast cancer at some point in her lifetime, bilateral oophorectomy could reduce her risk to 30 percent.

  Put another way, for every 100 women just like her, 60 could be expected to be diagnosed with breast cancer without oophorectomy. And 30 would be expected to be diagnosed with breast cancer after oophorectomy.

• Ovarian cancer risk by 80 to 90 percent. As an example, if a woman with a high risk of ovarian cancer had a 30 percent chance of being diagnosed with ovarian cancer at some point in her lifetime, oophorectomy could reduce her risk to 6 percent, assuming an 80 percent risk reduction.

  Put another way, for every 100 women just like her, 30 could be expected to be diagnosed with ovarian cancer without oophorectomy. And six would be expected to be diagnosed with ovarian cancer after oophorectomy.

In studies, the risk of breast cancer and ovarian cancer varies according to the particular gene mutations that you have. And your individual risk of breast cancer and ovarian cancer varies depending on many factors, including your age, your family history, your lifestyle choices and other strategies you're using to reduce your risk of cancer.

For some, oophorectomy may offer great reduction in risk. For others, the risks of surgery and the potential side effects may not be worth the reduction in cancer risk.