Ovarian Cancer & Hormone Replacement? What’s The Real Risk?
By Marina Johnson, M.D., F.A.C.E.
Recent headlines screamed out “HRT increases ovarian cancer risk by 43%!!” The critical question every woman asks is, “Does this mean I should stop taking hormone replacement???”
Before you toss your hormones, understand that life is full of risks. You could die in a car crash but that doesn’t keep you from getting in your car and driving to work, right? That’s because the absolute risk of dying in a car crash is 1 in 5000 and you accept that small risk.
In this February 2015 study published in Lancet, the reported risk of 43% was a “Relative Risk” but what you really need to know to make an informed decision is the “Absolute risk.” Absolute risk is very straightforward to understand. It compares the incidence of a particular risk in different groups. For example, if one person in 1000 in Group A gets a particular disease compared to 1000 people in Group B where two people get that same disease, the likelihood of that disease is still very rare in either group because 999 and 998 people, respectively, didn’t get the disease. Relative risk compares the risk between two different groups. If you describe this same phenomenon in terms of relative risk, you would report that the people in Group B had 50% more occurrence of the disease!
In the Lancet study, the increased absolute risk of dying from ovarian cancer caused by HRT was reported as 0.6 cases per 1000 women, which is only an increase 0.06%! That means that 99.94% of the women who took HRT did NOT die from ovarian cancer. What we know from other studies is that women who take HRT have 32% less heart disease, 50% less Alzheimer’s/dementia, 40% less osteoporosis and an improved life span of 39%.
This same pattern of reporting is often used in studies of HRT and breast cancer where statistically modest or borderline results are made to look more impressive than they actually are by reporting them as relative risk.
An interesting 2009 article making this point appeared in the Cancer Journal, reporting increases in relative risk of breast cancer not only with HRT but also with birth weight, fish intake, eating one additional serving of French fries per week during pre-school years, eating grapefruit, working on a night shift, working as an airline flight attendant, taking antibiotics and the use of electric blankets. What they reported is that the relative risks in almost all these cases was very low and the use of HRT was virtually the lowest, being less risky than eating fish or grapefruit, using antibiotics or being a flight attendant!
The decision to take HRT should not be swayed by sensationalistic headlines. Rather, it should be based on careful consideration of the real risks and benefits to be gained from HRT.
- Menopausal hormone use and ovarian cancer risk, Lancet, February 3, 2015
- Heron, M, et al, Deaths: “Final data for 2006,” National Vital Statistics Reports, 57(14), 2009
- Bluming AZ and Tavris C, “Hormone Replacement Therapy: Real Concerns and False Alarms, The Cancer Journal 15(2): 93-104, March/April 200
Marina Johnson, MD, FACE, a UCLA-USC trained physician, is a board-certified endocrinologist and pharmacist with no ties to any pharmaceutical company. She is a published author of “Outliving Your Ovaries: An Endocrinologist Reviews the Risks and Rewards of Treating Menopause with Hormone Replacement.”