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THC for Colon Cancer: Could Cannabis Be a Treatment?

Colorectal cancer is the third most-diagnosed cancer worldwide and a leading cause of cancer-related deaths. Affecting the colon and the rectum, this type of cancer can appear in either part of the large intestine, which processes food using beneficial bacteria.


Colon cancer is often diagnosed at advanced stages, limiting treatment options. The Centers for Disease Control and Prevention recommend regular colorectal screening for adults ages 45 to 75 years to promote early detection and treatment.


Potentially adding to the scope of available treatments, recent research on cannabinoids has shown promise in the treatment of cancer. Cannabinoid studies have increasingly reported anticancer properties, with THC most commonly providing relief or improving symptoms.


In this article, we’ll cover all aspects of colon cancer: its risk factors, signs and symptoms, and stages. Then, we’ll shift focus to recent research on treating colon cancer with cannabinoids, providing an idea of what to expect as this therapeutic approach evolves.

Risk Factors of Colon Cancer

The cause of colon cancer remains unknown. However, there are multiple risk factors, many of which are lifestyle-related. Potential risk factors of colon cancer include:

  • Personal history of polyps

  • Genetics and inherited syndromes such as Lynch syndrome and familial adenomatous polyposis (FAP).

  • Age

  • Diets high in saturated fats, red meats, and processed meats

  • Personal history of inflammatory bowel diseases, including ulcerative colitis or Crohn’s disease

  • Low physical activity levels

  • Being overweight or obese

  • Smoking

  • Excessive alcohol use

  • Personal history of other cancers

  • Family history of colon cancer and other cancers 

  • Race and ethnicity as it is more commonly seen in Eastern European Jews and people of African American, Asian, and Hispanic descent

Symptoms of Colon Cancer

Colon cancer usually goes undetected in the earliest stages. However, symptoms emerge as the disease progresses. People with colon cancer may experience one or more of the following:

  • Diarrhea or constipation

  • Loose, narrow stools

  • Blood in stool, making it look dark brown or black

  • Bright red rectal bleeding

  • Abdominal cramps or pain

  • Persistent feeling of having a bowel movement despite having one already

  • Weakness or fatigue

  • Unexplained weight loss

  • Low iron levels or anemia

  • Jaundice (if it spreads to the liver)

Stages of Colon Cancer

After being diagnosed, tests determine the stage of colon cancer. Staging is the process of knowing the size of the cancerous growth, if it has spread to other parts of your body, and how far it may have spread. Five stages are used to determine the severity of colon cancer:

  • Stage 0: Carcinoma in situ where cancer cells are found in the innermost layer of the colon

  • Stage I: Cancer has grown into the next layer of tissue

  • Stage II: Cancer has reached the outer layers of the colon but not beyond the colon

  • Stage III: Cancer has gone beyond the colon to nearby lymph nodes, tissues, or organs, but it has not spread to distant sites

  • Stage IV: Cancer has spread to distant lymph nodes or organs of the body


Cancer can recur after treatment. It may come back in the colon or in other organs such as the liver and the lungs.

Treatment of Colon Cancer

Various treatments are available for patients with colon cancer. The best type of treatment depends on multiple factors including the type and stage of colon cancer as well as the patient’s age, health status, and medical history. Colon cancer treatments can include one or more of these standard therapies:

  • Surgery

  • Chemotherapy

  • Radiation therapy

  • Radiofrequency ablation

  • Cryosurgery

  • Immunotherapy 

  • Targeted therapy


Clinical trials are ongoing to improve current therapies and invent novel treatments for patients with cancer. A recent investigation evaluated the effect of phycocyanin on colitis-related colorectal cancer. Phycocyanin provided anti-inflammatory benefits and inhibited cancer formation. Most intriguingly, there is also emerging evidence that cannabinoids might have use for colon cancer.

What Are Cannabinoids? 

Cannabinoids are compounds found in the Cannabis sativa plant. Cannabis contains over 100 cannabinoids. However, the two best-studied cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).


Delta-9-tetrahydrocannabinol, otherwise known as THC, has several therapeutic benefits. It is the principal compound responsible for the intoxication classically associated with cannabis use. Currently, the FDA has approved synthetic forms of THC to manage chemotherapy-induced nausea and vomiting as well as stimulate appetite in people suffering from AIDS.


CBD, on the other hand, is non-intoxicating. This compound, though, has yet to be approved to manage cancer or any cancer-related symptoms.

Cannabinoids and Colon Cancer

Over the past decade, literature has suggested that cannabinoids can be used to treat colorectal cancer. A 2016 study showed that THC can effectively inhibit cancer growth and metastasis.


While researching new therapies for colon cancer, scientists found that cannabis terpenes, including nerolidol, might have anticancer activities. A study investigated its anticancer properties in human colorectal cell lines by formulating solid lipid nanoparticles loaded with nerolidol to enhance solubility and stability.


Results showed that encapsulated nerolidol had an improved inhibitory effect on colon cancer cell progression than free nerolidol. It further revealed nerolidol had cytotoxic properties, resulting in apoptosis, a process of programmed cell death, of the cancer cells.


A similar study investigated the effect of alpha-terpineol on colon cancer. In this study, alpha- terpineol-PLGA nanoparticles coated with folic acid-chitosan (αT-PCF-NPs) inhibited the growth and decreased the size of malignant tumors.


A recent study delved into the mechanism of cannabidiol and its antitumor activities. CBD appears to inhibit the invasion and metastasis of cancer cells by lowering certain activator inhibitor levels. The results from the study showed that CBD treatment induced events that favored tumor cell death, including autophagy, a process of self-cell destruction, and apoptosis.


Current evidence suggests that cannabinoids and other essential compounds in cannabis can serve as potential treatment options for colon cancer in the next few years.

Using Cannabinoids for Colorectal Cancer: Dr. Goldstein’s Analysis

It is the opinion of esteemed cannabis researcher Dr. Bonni Goldstein that THC has properties that cause cancer cells to “commit suicide” (“Cannabis Is Medicine,” p.188). Dr. Goldstein cites a 2007 study published in the International Journal of Cancer titled “The cannabinoid δ9-tetrahydrocannabinol inhibits RAS-MAPK and PI3K-AKT survival signalling and induces BAD-mediated apoptosis in colorectal cancer cells.”


In the study, the authors eventually conclude that THC is relevant in cancer treatment largely due to its mediation of CB1 neuroreceptors, a primary component of the endocannabinoid system (ECS) and, it increasingly appears, a critical factor in cancer treatment. The facilitators of the study noted that THC modulated two critical chemical pathways involved in the development of colorectal tumors, indicating that the impact of THC — and, more specifically, CB1 — on colon cancer could be quite significant.

Summary: Can Cannabis Help with Colon Cancer?

Despite the wide availability of treatment, global colorectal cancer numbers show no signs of decreasing in the near future. Hardly any symptoms manifest in early stages of the disease, and even regular colorectal screenings designed to promote prevention often come too late. 


Intent on solving the issue once and for all, scientists continue to investigate novel treatments for colon cancer. It’s certainly true that recent studies suggest cannabinoids like THC and CBD might one day become respected as therapies for colon cancer. Both cancer patients and their physicians have reason to be hopeful that cannabis may be able to support or even replace existing therapies, and the medically preventive powers of cannabinoids are just as impressive.

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