Medical cannabis and bowel cancer: What you need to know

What is bowel cancer?

Bowel cancer is one of the most common forms of cancer diagnosed in the UK. There are an estimated 44,100 new cases every year, accounting for around 11% of all new cancer cases. The disease is most common in people over the age of 60, but it can occur in people much younger. Bowel cancer may also be called colorectal cancer, as it refers to cancers that develop in the colon or rectum. 

What causes bowel cancer?

The exact cause of bowel cancer is unknown; however, a number of factors are known to increase the risk of the disease. This may include family history, obesity, smoking, alcohol consumption, and diet. Having certain conditions, such as inflammatory bowel disease (IBD) and Lynch Syndrome, can also increase the risk of bowel cancer.

Signs and symptoms of bowel cancer

Early diagnosis helps to make bowel cancer more treatable, so being aware of the signs and symptoms of the disease is extremely important. Some common bowel cancer symptoms include:

• Blood in your poo or bleeding from your bottom
• Changes in your poo, such as experiencing more diarrhoea or constipation than usual
• Changes in your bowel habits, such as needing to go more or less often than usual
• Losing weight without trying or knowing why
• Feeling very tired
• Having pains and/or a lump in your tummy

Bowel cancer can also cause anaemia, a condition that causes your body to produce fewer red blood cells than usual. This can also contribute to tiredness and cause shortness of breath and headaches. 

Treatment for bowel cancer

The course of action for treating bowel cancer can depend on several factors, including the stage and size of the cancer, whether the cancer is in your colon or rectum, whether it has spread to other parts of the body, your age, and your general health. Some patients may be offered a combination of treatments. 

Treatments for bowel cancer can include:

• Surgery - To remove the cancer from the colon or rectum. This can include removing part or all of the bowel around the cancer.
• Chemotherapy - This may be necessary if you are unable to undergo surgery or if the cancer comes back after the procedure.
• Radiotherapy - May be necessary if you have cancer in your rectum or if the cancer has spread to other parts of the body.
• Medicines - You may be prescribed targeted medicines that kill cancer cells or immunotherapy, which helps your immune system kill cancer cells. 

In cases of more advanced bowel cancer, it may not be possible to cure the disease. In such cases, treatment will focus on slowing down the spread of cancer, managing symptoms, and prolonging life. 

Medical cannabis and cancer

Medical cannabis was legalised in the UK in November 2018. Since then, tens of thousands of patients have been prescribed cannabis-based medicines to manage a wide range of conditions. This includes many patients who have turned to medical cannabis to manage the symptoms of cancer and/or the side effects of conventional treatments. 

Inducing cancer cell death

While there is some research that indicates that cannabis extracts containing cannabinoids like THC may be effective in inducing death in some types of cancer cells; this research is still very much in its early stages, and it is in no means definitive. Therefore, currently in the UK medical cannabis is not prescribed in the UK to treat cancer itself, and in no way is it viewed as a cancer cure, but it can be prescribed to help manage its associated side effects and symptoms. 

Relieving chemotherapy-induced nausea and vomiting

Chemotherapy is a common treatment in many types of cancer. While it is often effective in killing cancer cells, it can also be associated with a wide range of side effects, including nausea and vomiting. When conventional approaches to managing this have failed, medical cannabis may be considered as a complementary therapy. 

A randomised, placebo-controlled trial, the results of which were published in 2024, found that a medical cannabis formulation (THC:CBD) improved the complete response rate in patients from 8% to 24% compared with placebo. Participants experienced improvements in nausea, a reduction in daily vomits, and were able to reduce their use of rescue medications. However, adverse events such as sedation and dizziness were relatively common.

Cancer-related pain

Cancer-related pain can refer to pain resulting from the cancer itself or the treatments used. Pain is common among patients with cancer and can significantly impact quality of life, making effective management extremely important. Some evidence indicates that cannabis-based medicines may be useful in managing pain, including that associated with cancer. 

A recent study analysed data from patients with cancer who were part of the Quebec Cannabis Registry to evaluate the safety and effectiveness of medical cannabis in reducing pain and concurrent medications. It found that medical cannabis was associated with a statistically significant decrease in BPI worst pain, overall pain severity, and pain interference at 3,6, and 9 months following treatment initiation.

Medical cannabis and bowel cancer - FAQs

Can medical cannabis be prescribed for cancer in the UK?

Medical cannabis can be prescribed as an adjunctive therapy in the UK to help manage cancer symptoms and the side effects of conventional treatments such as chemotherapy. However, medical cannabis is not considered to be a treatment for cancer itself.

What medical cannabis products are available for patients with cancer?

At Releaf, we offer a range of medical cannabis oils and flower products. If you are eligible for medical cannabis treatment, the most suitable formulation will be determined by your clinician following your consultation.

Can medical cannabis be prescribed as part of palliative care?

Yes, medical cannabis can be prescribed as part of palliative care for patients with terminal cancer. This type of treatment aims to provide symptom control to help make the patient as comfortable as possible throughout their end-of-life care.

Bowel cancer accounts for a significant proportion of cancer cases in the UK, making effective symptom control an important consideration in treatment. Current evidence indicates that medical cannabis may be beneficial in the management of some cancer symptoms and treatment side effects. 

Our team of specialist clinicians are always on hand to help. Complete our medical cannabis eligibility checker today to learn more.