Endometrial cancer (EC), the most common gynecologic cancer in the U.S., is on the rise. This year, the American Cancer Society estimates 63,280 women will be diagnosed with EC, and 11,350 will die from the disease.
Exposure to too much estrogen is believed to play a major role in the development of EC, because it can stimulate endometrial cells to grow and potentially become malignant. Women who have an increased risk of EC are those who:
- Use certain hormone replacement therapies (to treat menopause)
- Have started menstruating at an early age
- Never had children
- Are overweight or obese particularly after menopause
All of these factors increase a woman’s overall lifetime exposure to estrogen. Women with endometriosis—a pro-inflammatory disease in which tissues normally found in the uterine lining grow outside the uterus—are also at an increased risk of EC.
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What Role Do Cannabinoids Play When it Comes to Cancer?
Besides the well-known painkilling and anti-emetic effects of tetrahydrocannabinol (THC) and cannabidiol (CBD) in cancer patients, there’s mounting evidence that these cannabinoids may inhibit in-vitro growth of various types of tumor cells. Animal studies also show that THC and CBD may impair the ability of certain types of cancer cells to invade tissues and metastasize to other parts of the body.
However, the scales tip more toward CBD in the growing number of preliminary studies showing its potential to stop the growth and expansion of cancer cells.
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CBD Shows Therapeutic Promise With Hard-to-Treat Tumors
In a recent study, investigators from the University of Porto in Portugal tested the anti-cancer effects of THC and CBD in two endometrial cancer cell lines called Ishikawa and Hec50co. While Ishikawa is an estrogen-dependent EC cell line—meaning, it needs estrogen to continue to survive, Hec50co is able to develop other means of surviving without estrogen. ECs that don’t rely on estrogen to survive are more difficult to treat.
Researchers also treated the EC cells with the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG). AEA and 2-AG are compounds chemically akin to CBD and THC in cannabis.
What researchers found was that the cannabinoids worked in various ways to kill EC cells. In estrogen-dependent EC, AEA and CBD induced apoptosis—a process of programmed cell death—by activating a receptor called transient receptor potential vanilloid type 1(TRPV1). TRPV1 is involved in the transmission and modulation of pain. Previous studies have shown that CBD’s action to reduce sensitivity to pain is through this receptor.
They also found that when estrogen-independent EC cells were treated with AEA and CBD, it resulted in a drastic cytotoxic—toxic to cells—effect, independent of TRPV1. Meanwhile, THC treatment didn’t have any effect on either EC cell line, and none of the cannabinoids had any effect on normal, non-cancerous cells.
The University of Porto researchers concluded that CBD and CBD-rich extracts may be more promising than THC for the potential treatment of endometrial tumors. These findings show that CBD is effective in inhibiting tumor cell growth regardless of whether the tumor needs estrogen to grow.
Of course, more studies are needed to test these findings. However, this outcome suggests that CBD could have potential as a therapeutic agent for these hard-to-treat tumors.
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Can CBD Be Used to Treat Endometrial Cancer?
Clinical studies are needed to determine the potential efficacy and dose of CBD as a therapy for EC in humans. It may be that CBD could be used in combination with current EC therapies to enhance their tumor-killing actions. It should be noted that at this point, there’s absolutely no evidence in humans to support women solely using CBD to treat their EC.
Should Women Use Cannabis to Reduce the Risk of Endometrial Cancer?
Cannabis may help protect against EC and perhaps other cancers by lowering inflammation in the body. Chronic inflammation of tissues may lead to cellular DNA damage that could ultimately transform into cancer. This may be particularly relevant for women with endometriosis, which is a chronic inflammatory condition that affects endometrial tissues. Although THC wasn’t shown to inhibit the growth of EC cells in the University of Porto study, both CBD and THC are potent anti-inflammatory agents that can help reduce inflammation.
Lowering circulating estrogen levels may also reduce risk of EC. Early studies in rats have found that acute administration of THC or AEA resulted in lower circulating estrogen levels. So, daily consumption of tinctures containing CBD and THC may help lower EC risk by reducing inflammation and circulating estrogen levels.
Other Ways Women Can Guard Against Endometrial Cancer
Keep a healthy weight. Consuming an anti-inflammatory, anti-estrogenic diet can further protect against EC. Foods to avoid include:
- Sugar
- Red meat
- Alcohol
- Highly estrogenic foods such as soy and flaxseed
Foods to eat more of include:
- Green and other colored vegetables
- Cruciferous vegetables
- Foods containing anti-inflammatory and anti-estrogenic flavonoids such as green tea, apples and onions
Women may also want to add a specific type of seaweed to their daily diets. In animal, human and cell studies, which I conducted, an edible brown seaweed from the Maine coast called Fucus vesiculosus (aka bladderwrack) was found to have anti-estrogenic action and tumor-killing properties that can fight against endometrial, breast and ovarian cancer cells. It was also found that bladderwrack can effectively reduce pain and heavy menstrual bleeding in women with endometriosis.
Besides regulating circadian rhythms and reproduction, melatonin has shown promising results as an anti-inflammatory, anti-estrogen and anti-cancer agent. Studies have also shown that it reduces inflammation and may help slow the spread of endometriosis. Because of its popularity as a sleep aid, a number of melatonin supplements are now currently on the market.
Incorporating cannabis along with other dietary and lifestyle measures may help reduce a woman’s risk of EC, as well as provide other healthful benefits. That said, women experiencing any abnormal uterine bleeding or changes to their menstrual cycles should immediately consult with a physician.
Photo credit: Ant rozetsky
If you’re new to cannabis and want to learn more, take a look at our Cannabis 101 post. HelloMD can help you get your medical marijuana recommendation; it’s easy, private and 100% online.
