In the midst and even in the aftermath of treatment for breast cancer, it can be difficult to tell whether you’ve gone into menopause for good. For instance, maybe your periods stopped during chemotherapy but still haven’t returned a few months after finishing treatment. The younger you are, the better the odds are that they will return.
Knowing for sure whether or not you’re permanently in menopause is likely to matter most to you if you still want to have biological children. However, you may simply be curious about where you stand.
Your doctor may use the following blood tests to help you gauge this:
- Follicle-stimulating hormone (FSH). FSH is a protein made by the brain that stimulates ovulation. If your ovaries are beyond menopause, they no longer respond to FSH, and your brain reacts by sending out even more of these hormones. If your periods have stopped for some time, a persistently high level of FSH (over 40 milli-international units per milliliter, or mIU/mL) indicates that menopause may be permanent. Tracking your results over time is important because these levels can swing widely from day to day. For example, in a normal perimenopausal woman, it’s not unusual for her FSH level to be low one day and then quite high the next.
- Estradiol levels. Estradiol is the main form of estrogen found in premenopausal women. A normal level is 30-400 picograms per millileter (pg/mL), but after menopause, it falls below 30 pg/mL. If you’re taking tamoxifen, estrogen levels can be significantly increased above normal, so this test result may not give you an accurate picture of your status. One possible reason for the increased levels is that although tamoxifen acts against the effects of estrogen in breast tissue, it acts like estrogen in other tissue. However, we’re still not sure exactly why tamoxifen increases estradiol levels.
These blood tests are not the final answer to whether or not you are in menopause, however. Even if you have postmenopausal levels of FSH and estradiol, these levels can change over time. The longer you go without a menstrual period, and the longer that repeat testing suggests you are menopausal, the more likely it is that you are in this stage of life for good.
You may encounter other menopause tests that you can do at home, on your own, using urine or saliva. However, these tests aren’t considered reliable. If you’re interested in testing, be sure to discuss it with your doctor.
“If you have serial blood hormone tests over 12-18 months that are consistent with menopause, without any inching back toward premenopause, you are most likely in permanent menopause. That said, your periods can return after a long break. I have one patient who resumed her periods after 3 ½ years and several others who had their periods return between 18 months and 3 years. Keep this in mind if you are sexually active: use birth control if you don’t want to become pregnant — or until you’re sure you are in menopause for good.”
-- Marisa Weiss, M.D., president and founder, Breastcancer.org, breast radiation oncologist