Hormone Replacement Medical care And Breast Cancer
by:
Patricia T. Kelly, Ph. D.
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HORMONE REPLACEMENT Medical care AND BREAST CANCER: THE RISKS IN PERSPECTIVE
Janet M., a fifties-something woman, entered my office and aforesaid as she sat down, "I've see that if I take hormones I'll increase my breast cancer risk. I'm going crazy without sleep and with these mood swings, but I don't want to increase my breast cancer risk by taking hormones."
Like galore women, Janet had detected
that a recent study, the Women's Health Initiative (WHI), definitively showed that endocrine replacement medical care (HRT) increases breast cancer risk. Janet, like most people, didn't realize that this study found no statistically significant increase in breast cancer risk to women who took HRT.
When differences are not significant, an increase in risk may well be due to another factors, not the one being studied, such as HRT use. As often happens once
a medical story is reported, the emphasis was on the increase in risk, not whether the increase was likely to be due to the agent being studied or to the size of the risk.
The actual size of a risk is important in any woman's decision devising process. In this case the risk was passing small -- only 8 in 10,000 women a year -- which is 0.08% or eight hundredths of one percent! Janet was astonied to discover the actual size of the increase, and said, "You mean I was acquiring all concerned for a risk that small!"
"And," I pointed out, "even this really small difference in risk may not be due to endocrine use." I explained that breast cancers take an average of eight years to reach simply about half an inch in size. This means that breast cancers started in the 1st year of the study would-be not be detected for eight or much years. The study followed women for only simply about five years, so all or most of the breast cancers found were probably present in an undiscovered state before the study began.
Janet asked if HRT use mightiness have caused several breast cancers to grow much quickly and therefore be detected sooner than eight years. This is unlikely. A number of studies find that breast cancers in women who were exploitation HRT were not larger and were not dividing much quickly than breast cancers in non endocrine users. Since breast cancers grow much slowly in older women and the average age in this study was 63, breast cancers in this group would-be tend to grow much slowly and so take even as longer than the eight year average to be detected.
Women in the WHI study used a particular type of endocrine Prempro. The results of this study therefore do not apply to other, newer approaches in which much natural hormones are used and a woman's catamenial cycle is much closely approximated.
Janet was amazed to discover that galore studies find that women who use HRT do not have an increase in breast cancer risk compared to women who don't use hormones, even as once
hormones are used for twenty years. Also, in another large study in which several women were allotted to take Prempro and others not, women who used Prempro had no significant increase in breast cancer risk.
As Janet left, she said, "I can see now that once
I hear simply about a study I need to cognize how big a risk is and not simply that it is increased. I'll besides ask how long a study it was. This discussion has given me a whole several perspective."
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Patricia T. Kelly, Ph.D. is a medical biologist who specializes in providing information simply about cancer risk to individuals and health professionals. She is attached with Saint Francis Memorial Hospital in San Francisco. Information simply about her book, Assess Your True Risk of Breast Cancer, can be found on her web site: http://www.ptkelly.com.
Dr. Kelly is a medical biologist who has been a Specialist of the American Board of Medical Genetic science since 1982. In 1993 she became a Initiation Fellow of the American College of Medical Genetics. She received her Ph.D. in genetic science from the University of California, Berkeley.
