Cancer

Cancer is a disease in which cells grow uncontrollably within one area and then spread to other parts of the body. It can begin in any area of the body, with abnormal or damaged cells growing and multiplying when they shouldn’t. Such cells might grow into tumours, which may or may not be cancerous. These tumours may be life-threatening, with a particularly high risk associated with those in the brain.

There are five different types of cancer:

• Carcinoma – a cancer that begins in the skin or the tissues that line or cover internal organs. Subtypes include adenocarcinoma, basal cell carcinoma, squamous cell carcinoma and transitional cell carcinoma
• Sarcoma – a cancer that spreads via the connected tissues such as those of the bones, muscles, and cartilage
• Leukaemia – a cancer of the white blood cells. It commonly spreads from blood cell producing tissues, such as that of bone marrow
• Lymphoma and melanoma – cancers known to begin in the cells of the immune system
• Brain and spinal cord cancers – also known as central nervous system cancers

Chemotherapy is regularly used in the treatment of cancer, with chemotherapy-induced nausea and vomiting  (CINV) affecting up to 80% of patients. CINV may be categorised as acute, delayed, anticipatory, breakthrough, or refractory.

There are a number of signs associated with the early onset of cancer. People are encouraged to check and consult their GPs on the identification of symptoms such as:

• Changes in bowel habits lasting three weeks or more
• Bloating for three weeks or more
• Unexplained bleeding (this might be noticed after urinating, coughing, or being sick)
• Shortness of breath and chest pain
• Lumps on areas of the body such as the breasts or testicles
• Unexplained weight loss
• Stomach or back pain

Regular cancer screenings are also recommended for the early identification of such symptoms.

Cancer develops as a result of mutations or changes to the DNA make-up of cells. The mutations may be genetically inherited or occur after birth due to environmental factors. The risks are known to be increased as a result of exposure to physical carcinogens (such as radiation and ultraviolet (UV) light), chemical carcinogens (such as cigarette smoke and air pollution), or biological carcinogens (like viruses and bacteria).

Other risk factors include:

1. Chemotherapeutic agents (e.g. platinum-based therapies, such as cisplatin)
2. Radiation therapy
3. Non-chemotherapy medications
4. Cancer-related metabolic effects
5. Brain or spinal metastases

The surgical removal of tumours is typically the first option to be considered. Courses of chemotherapy might also be prescribed, involving but not limited to medication with 5-HT3 antagonists (e.g. palonosetron); Corticosteroids (e.g. dexamethasone); NK1 receptor antagonists (e.g. aprepitant); Dopamine receptor antagonists (e.g. metoclopramide and prochlorperazine); and Benzodiazepines. Radiotherapy is another choice, involving the controlled use of high-energy X-rays.

The THC medication Nabilone has been available to cancer patients suffering from CINV since the 1990s in instances where first-line treatment options have been found ineffective or unsuitable. There is also evidence also supporting the use of medical cannabis in relieving other cancer-related symptoms, including pain, anxiety and lack of sleep.

Research into the use of medical cannabis as a potential cure for different types of cancer is ongoing, however still at a very early stage, with encouraging preclinical data and some isolated positive case studies being reported, but little else at present.