Cancer

Cancer is a group of diseases characterised by the uncontrolled growth and spread of abnormal cells.

While treatments such as chemotherapy, radiotherapy, and surgery are often essential to combat the disease, these interventions can result in severe side effects, including nausea, vomiting, pain, appetite loss, and fatigue. These symptoms not only diminish patients’ quality of life but also make it difficult for them to tolerate and complete their treatment plans.

Common Conditions Related to Cancer (Treatment-Related Symptoms)

Cancer patients often experience a range of debilitating symptoms, including:

Chemotherapy-Induced Nausea and Vomiting (CINV): A common side effect of chemotherapy that can lead to dehydration, weight loss, and severe discomfort if not effectively managed.
Cancer-Related Pain: Pain may stem from the cancer itself (e.g., tumour pressure or bone metastasis) or result from treatments such as surgery, radiotherapy, or chemotherapy.
Loss of Appetite and Cachexia: Many cancer patients experience reduced appetite, leading to cachexia—a condition marked by extreme weight loss and muscle wasting.
Fatigue: Profound physical and mental fatigue caused by cancer and its treatments significantly impacts daily functioning and emotional wellbeing.
Anxiety and Depression: A cancer diagnosis and treatment often lead to mental health challenges such as anxiety and depression.
Sleep Disturbances: Cancer-related symptoms and treatments frequently disrupt sleep, exacerbating fatigue and reducing overall quality of life.

Conventional Treatments for Cancer-Related Symptoms

To address these symptoms, patients are often prescribed a range of conventional medications, including:

Antiemetics: Drugs like Ondansetron (Zofran), Metoclopramide (Reglan), and Dexamethasone are commonly used to control nausea and vomiting. Although effective, they may cause side effects such as headaches, dizziness, and constipation.
Opioids: Medications such as Morphine, Oxycodone, and Fentanyl are prescribed for severe cancer-related pain. However, opioids carry risks of dependency, sedation, and constipation, and may not always provide adequate relief.
Appetite Stimulants: Megestrol acetate (Megace) and Dronabinol are used to increase appetite in patients with cachexia, but they can have side effects like fluid retention or altered mental states.
Anxiolytics and Antidepressants: Medications such as Lorazepam (Ativan) and selective serotonin reuptake inhibitors (SSRIs) are prescribed to manage anxiety, depression, and emotional distress during treatment.
Steroids: Corticosteroids like Dexamethasone are used to reduce inflammation, stimulate appetite, and alleviate certain symptoms.

While these treatments are effective for some patients, they often carry significant side effects that further burden individuals undergoing cancer care. Consequently, many cancer patients seek complementary therapies, such as medical cannabis, to manage symptoms with fewer adverse effects.

How Cannabis Can Help

Medical cannabis has emerged as a promising complementary therapy for cancer patients, particularly in managing symptoms related to chemotherapy and other treatments. Cannabinoids such as tetrahydrocannabinol (THC) and cannabidiol (CBD) interact with the body’s endocannabinoid system (ECS), which plays a role in regulating pain, nausea, appetite, and mood. Research indicates that cannabis-based therapies may effectively address many of the key symptoms experienced by cancer patients.

Cannabinoids and Cancer Symptom Management: Clinical Evidence

Chemotherapy-Induced Nausea and Vomiting (CINV)

A 2016 systematic review in JAMA found that cannabinoids were more effective than conventional antiemetics, such as Ondansetron, in reducing chemotherapy-induced nausea and vomiting.
A 2020 clinical trial in Annals of Oncology investigated the use of Nabiximols (Sativex), a cannabis-based spray containing both THC and CBD, for managing CINV. Patients who used Nabiximols experienced significant reductions in nausea compared to those given a placebo.
A meta-analysis in The Cochrane Database of Systematic Reviews confirmed that Dronabinol, a synthetic THC, was effective in controlling CINV when other treatments failed.

Cancer-Related Pain

A 2018 study published in The Journal of Pain demonstrated that medical cannabis, particularly THC, could reduce pain severity and opioid use in cancer patients, offering comparable relief with fewer side effects.
A 2020 clinical trial in The Lancet Oncology found that Nabiximols significantly alleviated pain in patients with opioid-resistant cancer pain.
A 2019 study in Frontiers in Oncology noted that cannabis provided pain relief while improving quality of life, with fewer cognitive impairments and reduced addiction risks compared to opioids.

Appetite Stimulation and Cachexia

A 2011 study in The Journal of Supportive Oncology showed that Dronabinol was effective in improving appetite and reducing weight loss in cancer patients.
A 2014 study in The British Journal of Clinical Pharmacology found that THC stimulated the release of ghrelin, the “hunger hormone,” resulting in increased food intake and improved nutritional status.
A 2019 trial in Cancer Management and Research reported that cannabis use enhanced appetite and helped patients undergoing treatment maintain body weight and strength.

Fatigue and Sleep Disturbances

A 2019 review in Cannabis and Cannabinoid Research found that balanced THC-CBD products improved sleep quality and reduced fatigue in cancer patients.
A 2020 observational study in The Journal of Pain and Symptom Management revealed that patients using cannabis reported better sleep patterns and reduced daytime fatigue compared to those relying solely on conventional medications.

Anxiety and Depression

A 2021 study in Frontiers in Psychiatry indicated that cannabis use reduced anxiety and improved mood in cancer patients experiencing treatment-related stress.
A 2019 study in The Permanente Journal demonstrated that CBD reduced anxiety in patients with anxiety disorders, including those undergoing cancer treatment, without causing psychoactive effects.

Mechanisms of Action

Cannabis exerts its effects primarily through the endocannabinoid system (ECS), which regulates processes such as pain perception, mood, appetite, and nausea:

THC: Binds to CB1 receptors in the brain and nervous system, reducing pain, stimulating appetite, and alleviating nausea. Its psychoactive effects can also help reduce anxiety and promote relaxation.
CBD: Does not produce psychoactive effects but indirectly modulates the ECS by enhancing natural endocannabinoids and interacting with serotonin receptors. CBD can reduce anxiety, improve sleep, and counteract some negative effects of THC, such as sedation.

Advantages Over Conventional Treatments

Medical cannabis offers several benefits compared to traditional therapies for managing cancer-related symptoms:

Fewer Side Effects: Unlike opioids, antiemetics, and other medications, cannabis (particularly CBD-dominant formulations) generally has a more favourable side effect profile.
Reduced Opioid Dependency: Cannabis can decrease the need for opioid analgesics, lowering the risk of dependency and overdose.
Comprehensive Symptom Relief: Cannabis addresses multiple symptoms—such as pain, nausea, anxiety, and appetite loss—simultaneously, providing a versatile treatment option for cancer patients.

Conclusion

Medical cannabis, especially products containing both THC and CBD, has shown significant potential in managing cancer-related symptoms such as chemotherapy-induced nausea and vomiting, pain, appetite loss, anxiety, and sleep disturbances. By interacting with the endocannabinoid system, cannabis offers a holistic and safer approach to symptom relief, with fewer side effects and less risk of dependency compared to many conventional medications. By adhering to strict regulatory guidelines, healthcare providers can offer cancer patients access to cannabis-based therapies, improving their quality of life and helping them better tolerate their treatments.