HRT may be Linked to Decreased Risk of Colorectal Cancer

Hormone replacement therapy (HRT) may reduce the risk of colorectal cancer in women, especially after therapy is completed, a new study suggests.

HRT is medication containing one or more female hormones, commonly estrogen plus progestin (synthetic progesterone). The hormones are available in a variety of forms: pills, vaginal creams, vaginal ring inserts, implants, injections and patches worn on the skin. HRT is typically prescribed to treat menopausal symptoms, but it may also protect against osteoporosis.

Early studies have shown that HRT may increase the risk of breast cancer, heart problems and stroke. For this reason, doctors generally prescribe the lowest possible dosage for the shortest period of time when treating symptoms of menopause.

Researchers from the University of Minnesota School of Public Health evaluated the association between HRT and colorectal cancer risk in 56,733 postmenopausal women participating in the Breast Cancer Detection Demonstration Project follow-up study. The women were followed for about 15 years.

According to the findings, published in Cancer Epidemiology, Biomarkers and Prevention, women who previously took a combination of estrogen and progestin at least five years earlier had a 45 percent reduced risk of developing colorectal cancer. 

The authors also found that women who had previously taken estrogen alone had a 17 percent decreased risk of developing the disease. Women who were currently taking estrogen had a 25 percent reduced risk, while those using estrogen for 10 year or longer had a 26 percent reduced risk.

It is unclear exactly how HRT may influence the risk of colorectal cancer. Additional research is warranted in this area.

For more information about HRT and menopause, please visit Natural Standard’s Medical Conditions database.

Comments

[Luce]

HRT has been shown have protective effects against colorectal cancer, but this study was in post-menopausal women who took it for short period of time. Other studies have actually stated that post-menopausal women on HRT for more than five years might have no additive effects.

This new study is confusing to me, as their patients were followed for 15 years. I would like to know if they had any of the side effects that are associated with HRT?

It is important for us to remember that HRT is not recommended for everybody, so women not experiencing menopause should not request HRT from their physicians for the prevention of colorectal cancer because there is no evidence available for this population yet.

[Mariane]

The use of postmenopausal estrogen has been shown to decrease the incidence of colorectal cancer. However, this inverse association between hormone use and mortality was most evident among women whose duration of use was less than five years. Longer durations and past use were not associated with significant survival benefits. Unfortunately, women who have had hysterectomies (removal of the uterus and sometimes the cervix) are limited to estrogen alone, whereas those with intact uteruses should take the combination of both estrogen and progesterone because the progesterone is known to lower the risk of endometrial cancer.

Also, breast cancer risk is increased when both hormones are combined, versus taking estrogen alone. Studies show that about 25% of breast cancer patients have tumors that are HER2+. HER2 stands for Human Epidermal growth factor Receptor 2. This receptor is found on the surface of normal cells and is involved in then normal growth and proliferation of normal cells.

However, cancer cells have a higher concentration on their surface and hence can divide and spread more quickly. Estrogen can bind to the HER2 receptor and induce their rapid growth. That is why it MAY cause or worsen breast cancer in certain populations.

[Cathy. P]

There is still much controversy surrounding hormone replacement therapy (HRT) that I doubt the results of this study will increase the usage of HRT. I know two women personally who did develop breast cancer within a few years of taking HRT. They were prescribed HRT before long-term study results were widely known. I wonder though, if various doses of HRT could be used in those considered at risk for colorectal cancer? Sounds like more studies are needed to determine the factors associated with decreased risk first.

[Steve]

I agree with Cathy. After HRT was linked to the development of breast cancer, many women were weary of beginning treatment. I don't think one study is sufficient to conclude that HRT has a positive effect and can prevent the development of colorectal cancer.

[Margaret]

Does anyone know if HRT is still effective for managing menopausal symptoms, although doctors now use lower dosages and shorter treatment times?

[Jess R.]

Mariane, are you saying that the benefits seen in this study could be due to the fact that the women were taking estrogen alone and not both estrogen and progesterone? I am confused by the abstract and not sure what group in this study experienced the greatest reduced risk of developing colorectal cancer.

[Cara]

In my opinion, I would leave HRT as a last resort option. True, there are benefits to estrogen and progesterone in the body, but the side effects may outweigh the benefits. It's also important to note that a woman should not be taking hormones to prevent the likeliness of getting colorectal cancer. IF the risks outweigh the benefits, then that side effect is simply an added bonus, it's not something to pursue.

[R. Hart]

Considering all the recent findings relating particular therapies, diets, genetic factors, etc. to their increased or decreased risk of cancers must present for a rather complex but fascinating calculus for the modern clinician. Balancing quality of life vs. statistical risk, one cancer vs. another…it’s something I don’t envy…or look forward to for that matter. Getting old is still bad for your health it seems. Hopefully, we’ve more good news to look forward to in the short-term with respect to treatments like HRT. Colorectal cancer is one of the scourges of the Western World, and reducing its incidence would save many lives.

[Luce]

Margaret,
HRT is still an effective for treatment for menopausal symptoms and like you said lower dosages are being used and for short period of time, many physicians prefer no more than five years. I believe this is due to the numerous studies all with different objectives and conclusions. But the most talked about trial was the Women Health Initiative trial on HRT that used lower dosages and their patients were followed for over 10 years. So this study found out that after five years on HRT there was that increased in the of breast cancer so recommended therapy for no more than five years.

[mary]

I would be scared of taking HRT for the risks of heart problems, stroke and increased risk of breast cancer, which have been found to be statistically significant. Although some good can be found with the treatment, I wonder if the benefit outweighs the risks.

[Luce]

Mary,

If the time comes for you to be on an HRT regimen, discuss your options with your physician, he/she will present the evidence to you, and then based on that, you can make the judgment. But I will assure that benefits vs. risks varies among individuals. Some people have predisposing risk factors that might make their risks of having any of the side effects greater than the benefits, but again, some are willing to take that risk just to be comfortable under their own skin.

Also one might not qualify for oral estrogen therapy, but remember that there are topical creams and gels, which reduce the amount of estrogen that absorbed into the bloodstream but still have same effects as oral therapy.

[Luce]

It is also important that patients with histories of blood clots or breast cancer are not candidates for HRT. This is because it increases their risk of experiencing additional blood clots and the recurrence of cancerous cells.

[Maggie]

It is also important that patients with histories of blood clots (especially smokers, age ≥ 35years) and/or breast cancer are not candidates for HRT. This is because it increases their risk a blood clots and recurrence of cancerous cells in the case of breast cancer.

[Josh]

Postmenopausal estrogen use has been shown to decrease the incidence of colorectal cancer. However, longer durations (past five years) and past use were not associated with significant survival benefit. Women with intact uteruses should take the combination of both estrogen and progesterone because the progesterone can help lower the risk of endometrial cancer. Also, breast cancer risk is increased when both hormones are combined. Good study, but I’m not surprised by the results considering that other studies that have looked at the effects of estrogen on different types of cancers.

[Sully]

HRT is not recommended for everyone, particularly smokers or patients with histories of blood clots.

[VLN]

I agree with what Sully said. I've heard of many complications from taking HRT. If I was told to take it as a preventative method, I would be very hesitant to do it.

[Jer M.]

I'd have to go with the general consensus here -- they're are so many other risk factors from HRT that I don't think it should become a mainstay for prevention of colorectal cancer. With this therapy, we would just be trading one cancer for anther, which isn't ethical at all. For the women who truly need HRT, I hope the best for them, and hopefully the prevention of colorectal Cancer is an added benefit. But I wouldn't prescribe widespread use.

[TPS]

What are some of the lifestyle modifications that women can undergo to decrease the risk of developing colorectal cancer? As many of these comments have stated, HRT may pose some harmful effects. Can a healthy diet and/or exercise actually decrease the risk of this disease? If so, it would be interesting to compare this reduction with the reduction associated with HRT.

[MHD]

I have read studies that counter the argument that HRT, when given in moderation, causes breast cancer. I think estrogen therapy is a great thing for menopausal women in that it prevents an even bigger issue: osteoporosis. Not only is estrogen needed for bone health and Calcium metabolism, but it is also needed for vitamin D conversion. This is a very important point, as the last few years of research have proven the need for vitamin D for the prevention of major diseases, cancers and illnesses. So although a little estrogen may provide an increased risk for breast cancer, it is decreasing the risk (by much higher proportions) of skin cancer, colon cancer, pancreatic cancer and depression.

[Hannah]

I thought it was already known that HRT decreases the risk of colorectal cancer according to previous research. I guess this new study has a pro of a longer study period of 15 years. However, we know today that HRT has lots of adverse effects as well. I would be interested to see the report on the long-term side effects of HRT.

[sphin]

I agree that not only is estrogen needed for bone health and calcium metabolism, but it is also needed for vitamin D conversion.You have a very informative blog keep posting.