Ovarian suppression may improve survival outcomes in breast cancer patients
All women produce a hormone called estrogen which stimulates some breast cancers to grow. In the context of breast cancer, ovarian suppression is the term used to prevent the ovaries from producing estrogen, which will then deprive the breast cancer cells of the hormones they need to grow. This can be either temporarily by hormone therapy or permanently by surgery.
Previously, we published research that suggests that removal of uterus, tubes and ovaries will improve life-expectancy in women diagnosed with breast cancer. Now, results published in the New England Journal of Medicine confirmed these findings in a large clinical trial.
Who may ovarian suppression be offered to?
Ovarian suppression may be suggested if a women’s breast cancer is estrogen receptor positive (ER+ cancer) and pre-menopausal. Women who receive the diagnosis of estrogen receptor positive breast cancer before the age of 35 years are at an increased risk for recurrence. High-level research published recently suggests ovarian suppression may reduce the risk of a cancer recurrence.
Certain hormone therapies ‘turn off’ estrogen produced by the ovaries. This treatment is given as an injection. However, once the therapy is stopped, in most cases the ovaries begin producing estrogen again.
Ovarian suppression by surgery will turn off the estrogen production permanently by removing the ovaries, which will start menopause straight away. An operation to remove the ovaries is called an oophorectomy, and the fallopian tubes should be removed at the same time. This is done using laparoscopic ‘keyhole’ surgery with short recovery.
Ovarian suppression combined with tamoxifen
In women at high risk of breast cancer recurrence they may benefit from treatment with ovarian suppression plus tamoxifen or an aromatase inhibitor.
Findings published from the TEXT and SOFT trials have found the addition of ovarian suppression to tamoxifen lengthened survival rates among premenopausal women with breast cancer.
In the SOFT trial, women were assigned to receive tamoxifen alone (1,021 women), tamoxifen plus ovarian suppression (1,024 women), or exemestane plus ovarian suppression (1,021 women). In the TEXT trial, researchers randomly assigned patients to tamoxifen (1,334 women) or exemestane (1,338 women), both with ovarian suppression. Women received treatment for 5 years in both studies. Exemestane is a hormone therapy used in postmenopausal women to decrease the amount of estrogen the body produces.
After a median follow-up of 8 years, the SOFT and TEXT trials have found that the 8-year disease-free survival rate (meaning the patient survives without any signs or symptoms of that cancer) was:
- 78.9% among patients who received tamoxifen alone,
- 83.2% among patients who received tamoxifen plus ovarian suppression, and
- 85.9% among patients who received exemestane plus ovarian suppression.
Overall 8-year survival (where patients diagnosed with the disease are still alive) was assessed:
- 91.5% among patients who received tamoxifen alone,
- 93.3% among patients who received tamoxifen plus ovarian suppression, and
- 92.1% among patients who received exemestane plus ovarian suppression
What are the implications of this research?
The researchers concluded that ‘among premenopausal women with breast cancer, the addition of ovarian suppression to tamoxifen resulted in significantly higher rates of both disease-free and overall survival than tamoxifen alone. The use of exemestane plus ovarian suppression resulted in even higher rates of freedom from recurrence.'
Note: Prof. Obermair does not treat patients for breast cancer but works closely with breast cancer specialists. He offers women diagnosed with breast cancer, risk-reducing prophylactic surgery to extend their lives.
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