Cancer continues to be a global epidemic that has seen a lot of research go into its diagnosis and treatment. Precision medicine (which depends on a genetic understanding of a cancer) is one of the major developments that have led to more effective treatment of this disease.
Genetic understanding is determined by DNA sequencing also known as genetic testing or genetic profiling. This is basically testing a sample of tumour tissue to determine the changes in the genes that have led to it becoming cancer.
By having this understanding, doctors can then offer treatment that targets genetic changes that lead to cancer development and growth. These genetic changes are also known as alterations or mutations.
Unlike chemotherapy that kills all cells, targeted therapy only destroys the specific factors that aid in the growth and development of cancer in the body.
Where does immunotherapy come in as far as precision medicine is concerned?
Immunotherapy has been in use even before this term was coined. Some examples include:
- Adoptive cell transfer which involves removing t-cells (a type of immune cell) from the tumour and after changing them in a lab, they are put back into the body to fight cancer.
- Monoclonal antibodies that are used to trigger the immune system to fight cancer.
Immunotherapy, also referred to as biological therapy, involves using substances made by the body or manufactured in a lab to boost the body’s immune system to enable it fight cancer. With precision medicine, doctors are able to determine which patients can benefit most from this treatment.
Using genomic information or other information in the microbiome, doctors can also determine which combination of immune drugs should be used for individual cancer patients.
Successful Immunotherapy Treatment for Leukaemia and Lymphoma
Chimeric antigen receptor T-cell therapy (CAR T-Cell therapy) is an adoptive cell therapy which has been successful in treating blood cancers like leukaemia and lymphoma. Receptors are special protein molecules found inside or on the surface of cells that bind to substances and change the cell.
This therapy works by taking T-cell samples of the blood and adding gene and CAR to make them CAR T-cells. Once they have multiplied in a lab, they are returned to the bloodstream, and they then attach to other antigens on the cancer cells to be able to fight the cancer.
Metastatic is a term used to refer to cancer that has spread to other parts of the body like the liver, lungs and brain. Immunotherapy is one of the best treatments for metastatic melanoma.
- Anti-PD1 inhibitor: These medications are used to help T-cells fight cancer by making cancer cells easier for the immunity to spot and fight them more effectively. Examples include Nivolumab and Pembrolizumab.
- Anti-CTLA-4 inhibitor: Medications like Ipilimumab are used to block the CTLA-4 protein which stops T-cells from attacking healthy cells and instead, enables them to fight melanoma cells.
- Interleukin-2: This drug is used to boost the entire immune system and stop cancer from multiplying and spreading. Cancer cells can also be spotted as they produce a chemical enabling T-cells to track and kill them.
- Oncolytic virus therapy: This treatment involves using a genetically modified form of the herpes virus to kill melanoma cells in the lymph nodes or skin.
- Combination therapy: It involves combining medication that boosts T-cells and another that boosts the immune system as they work better together than alone.
Apart from melanoma, other cancers that can be treated using immunotherapy include breast cancer, lung, kidney, prostate, stomach and bladder cancers.
- MEK inhibitors such as Binimetinib and trametinib work with the BRAF gene and changes in the BRAF gene are experienced in approximately half of the people with melanoma. Drugs like Dabrafenib and Encorafenib help shrink and slow down the growth of a tumour.
C-KIT inhibitors: Changes in this gene help in the growth of some melanoma tumours, therefore, drugs such as Imatinib can be used to stop changes in this gene.
The treatment of lung cancer depends on the size, location and stage of the cancer. Once the specialist has determined these factors, they can then choose the most appropriate treatment option.
- Surgery: This is probably the first step in treating most cancers. However, the lungs are very delicate organs and therefore, any surgical procedure of the lungs needs to be handled with care. The different types of surgeries for lung cancer include:
1. Lobectomy: Involves removal of one lobe of the affected lung.
2. Segmentectomy: When lobectomy is not possible, cancerous tissue can be removed from the lung through this procedure.
3. Pneumonectomy: Removal of the entire lung.
4. Wedge resection: This procedure, on the other hand, involves removing a small part of the lung with the tumour.
At our partner hospitals, video-assisted thoracic surgery (VAT) and Robotic-assisted thoracic surgery is done to perform minimally invasive surgeries which allow for faster healing, shorter hospital stays and less scarring as small incision are made during surgery.
- Radiotherapy: This therapy focuses on using high energy beams to kill cancer cells and prevent them from growing and spreading to other organs. One advanced form of radiation therapy that can be used for lung cancer treatment is brachytherapy which delivers high doses of radiation using implants that are placed inside the tumour.
- Targeted therapy: This type of therapy uses drugs to destroy cancer cells without causing harm to normal cells.
- Combination therapy: In this treatment option, the specialist uses a combination of therapies depending on what is most appropriate.
Side Effects of Immunotherapy
The majority of cancer treatments have side effects which may differ depending on the individual. These side effects arise from the treatment attacking healthy cells.
Immunotherapy can cause symptoms similar to those of a flu. These flu-like symptoms include dizziness, fever and nausea or vomiting. Others may include:
- Shortness of breath and
- Rashes and/or blisters
Find out from your doctor or specialist how you can deal with side effects brought about by your medical treatment.