Breast cancer is a major and growing health issue among women. Invasive breast cancer is the most common type cancer affecting women worldwide, and the second-most-common type overall, according to the Susan G. Komen foundation. This year, an estimated 232,000 cases will be diagnosed just in the US. Early detection and successful treatment are crucial for survival.
Numerous studies show that cannabinoid receptors are over-expressed in the tumour cells of certain cancers, such as cancers of the liver, lung, prostate and breast. Thus, researchers have been led to believe that the endocannabinoid system may be up-regulated in cancer in an innate biological effort to fight off this disease.
Studies also show that when cannabinoids are administered and bind to these receptors, they are able to inhibit cancer cell growth by preventing the proliferation of cancer cells and by inducing cancer cell death (apoptosis). Furthermore, cannabinoids have been found to impair both tumour angiogenesis – the increase in localized blood flow induced by tumour cells – and metastasis – the spreading of cancer to other organs.
CANNABINOIDS AND BREAST CANCER
There has been great medical advancements in breast cancer in recent decades, but certain breast tumors continue to be resistant to conventional treatments. Breast cancer is comprised of tumors that are distinct in their molecular profiles, leading medical professionals to categorize the disease into 3 main subtypes.
Research suggests that synthetic cannabinoids and phytocannabinoids (mainly THC and CBD) may be useful in treating all 3 subtypes of breast cancer, with the strongest evidence of therapeutic potential pointing to treatment of HER2-positive and triple-negative breast tumors. The therapeutic potential of cannabinoids is particularly important for patients with triple-negative breast cancer, as there is no standard therapy that currently exists and prognosis for this group of patients is poor.
In addition to their anti-cancer effects, research also shows that cannabinoids are considerably safer and less toxic than conventional treatments. Cannabinoids are non-toxic to non-tumor cells and are well tolerated by patients – only eliciting relatively mild side-effects such as dizziness and fatigue.
“This compound offers the hope of a non-toxic therapy that could achieve the same results without any of the painful side effects.” – Dr. Sean McAllister
In 2007, Dr. Sean McAllister and his team of researchers were one of the first to discover that CBD’s cancer-fighting properties could be successfully applied to breast cancer.
As it turns out, cannabinoids can provide a variety of other benefits in the treatment of cancer, including the prevention of nausea and vomiting associated with standard chemotherapeutic treatments and reduction of cancer-associated pain. Research also shows that, when combined with conventional cancer treatments, cannabinoids are able to induce a synergistic action against cancer and tumor cells, suggesting that the combination of conventional and cannabinoid-based treatments may more powerful than the administration of either treatment alone.
CLINICAL APPLICATIONS: THE CURRENT STATE
Scientific research on the effects of cannabinoids on breast cancer has been limited to preclinical trials involving cell cultures and animal models. Researchers believe that further preclinical trials are necessary to identify which patient population is the most appropriate for cannabinoid treatment and which cannabinoids specifically present the best therapeutic option for patients before trials can advance to the clinical stage.
Until these factors are established, it is unlikely that oncologists will be willing to prescribe cannabinoid-based medicine for the treatment of breast cancer, despite the fact that research authors continue to assert the need for health professionals to be aware of cannabinoid research.
In an update (2013) published in the Oncology Nursing Forum, associate editor Susan Weiss Behrend concluded:
“…cannabinoids have demonstrated anti tumor activity in preclinical breast cancer models. Practicing oncology professionals need to be aware of the clinical potential of these agents…” – Susan Weiss Behrend, RN
According to doctors and patients we have worked closely with, breast cancer tumours can be effectively treated with cannabis oil. However, they caution, the ratios of the tumour-busting cannabinoids THC and CBD must be matched to the classification of breast cancer – with certain kinds of breast cancer, namely those that are estrogen-positive, the tumour will actually
According to doctors and patients we have worked closely with, breast cancer tumors can be effectively treated with cannabis oil. However, they caution, the ratios of the tumor-busting cannabinoids THC and CBD must be matched to the classification of breast cancer—with certain kinds of breast cancer, namely those that are estrogen-positive, the tumor will actually grow if too much THC is used.
Although there are many types of breast cancer, they are usually grouped into four categories, depending on how they show up on diagnostic tests:
- Estrogen receptor positive (ER+) or progesterone receptor positive (PR+): About two in three cases of breast cancer (more in older women) have receptors for one or both of these hormones.
- HER2/neu (a.k.a. HER2 or ErbB2): HER2/neu is a protein that is over-copied by certain types of breast cancer. HER2-positive cancers spread more rapidly than other types of cancer.
- Triple negative: These breast cancers do not have estrogen or progesterone receptors and don’t show overproduction of HER2. Triple-negative breast cancers spread aggressively because they don’t respond to hormones or drugs that target HER2, but chemotherapy is an option.
- Triple positive: These types of breast cancer are ER+ and PR+, and they have too much HER2 production. They can be treated with hormones, HER2 drugs, and chemo.
Research has shown that PR+, HER2-positive, and triple-negative breast cancers can be effectively treated with cannabis. The protocols recommended by doctors we work with tend to have high THC-to-CBD ratios, often around 4:1.
Cancers that involve estrogen, however, may actually spread in response to large amounts of THC. Patients with ER+ or triple-positive breast cancer do better with lower ratios of THC to CBD—a ratio 1:1 or 1:3 is preferable, according to doctors and patients we’ve spoken with.
This recommendation comes from doctor and patient experience, not from clinical evidence. Although we have been unable to find any research on this, UPG is hearing from doctors, nurses, and patients that these dosages are best for treating these different types of breast cancer.