Immunotherapy: A New Form Of Cancer Treatment?
In 2018, there were over 9.6 million cancer deaths and this number is set to rise by 20% during the next 20 years (1). Thankfully, breakthroughs in medical science have offered healthcare practitioners new options in the treatment of cancer. Among the most promising new approaches is using immunotherapy to reactivate the immune system to destroy cancer cells (2).
This will be one of the key themes at the European Society for Medical Oncology (ESMO) Summit Africa 2019, to be held from 15 to 17 February in Cape Town. ESMO is the leading professional organization for medical oncology. Summit Africa will put into local context the most significant treatment advances presented at the ESMO annual Congress in Germany in 2018.
Immunotherapy treatment and cancer
The development of immunotherapy treatment for cancer patients is progressing rapidly. In fact, more patients are experiencing remarkable responses to these treatments that are allowing them to lead longer, healthier lives.
“At present, 95% of treatments in clinical trials or expanded access programmes comprise of chemotherapy, radiation or surgery, with immunotherapy at just 5%,” says Professor Bernardo Rapoport, Medical Oncologist and Extraordinary Professor of Immunology at the University of Pretoria, “However, in the 15 years those figures could be reversed.”
As news stories highlight these ground-breaking results, patients are beginning to wonder, ‘What is it? Is it a cure? Could it be right for me?’
Immunotherapy is a type of treatment that helps the body’s immune system attack cancer. Unlike other cancer treatments such as chemotherapy or radiotherapy which aim to remove cancer cells, this treatment is aimed at utilizing the body’s own immune response to destroy cancer cells.
Recent advances in immunotherapy for melanoma and lung cancer continue to significantly impact the treatment of both of cancers. Also, these impacts are influencing progress in the treatment of several other cancer types.
Immunotherapy drugs are now used to treat many different types of cancer. But immunotherapy is not for everyone.
Some immunotherapy treatments are patient-specific and depend on the exact type of cancer the patient has. The patient’s doctor will need to determine their eligibility based on treatment criteria, including a functioning immune system. It is important for the patient to discuss all available treatment options with their doctors in order to determine the best treatment for their specific diagnosis.
The role of biomarkers
Each patient is unique, yet therapies are expected to bring about the same desired outcome in every instance. A deeper understanding of how best to treat individual patients is gained when immunotherapies are complemented with a biomarker diagnostic test (4).
Biomarkers are key to determining appropriate treatment. A biomarker is a measurable biological factor that can tell us about certain aspects of human health. In the context of cancer immunotherapy, biomarkers can provide insights into each patient’s individual cancer – its genetic makeup, its behavior, and its interactions with the immune system – which doctors can then use to determine the approach most likely to benefit a particular person.
“A biomarker indicates that there is a specific target on or in a tumor cell which can be targeted by a specific anti-cancer drug and those tumors with such a biomarker will respond to the drug, while those without will not,” explains Professor Simon Nayler, Director and Pathologist at Drs Gritzman & Thatcher Inc. “Pre-treatment biomarkers predict this response. They may be a protein or molecule either in or on a tumor cell, and this may be established by immunohistochemistry or molecular testing such as polymerase chain reaction (PCR) or gene sequencing (NGS).”
There are several types of cancer immunotherapy aimed at helping immune cells recognize cancer cells. This can then increase the efficiency of the anti-cancer immune response.
- Stimulating a non-specific anti-tumor response by administering cytokines, synthetic molecules or hormones. Cytokines are most commonly used. They regulate growth and development of immune cells, increasing the immune response against cancer cells.
- A nonspecific response can also be stimulated by injecting activated T cells into a person with cancer. Clinical trials of this type of therapy are ongoing.
- Vaccines that contain genetic material from tumors or viruses (some cancers are caused by a virus) can be administered to a person with cancer. By increasing the exposure of the immune cells to these antigens, the immune system mounts an attack on specific cancer cells bearing that antigen and retains a memory of that antigen for the future. Current vaccines are aimed at preventing cancer (HPV vaccine to prevent cervical cancer, hepatitis B vaccine) or its recurrence. Vaccines aimed at fighting existing cancers (including lung, prostate, bladder, colorectal, kidney and brain cancers) are in development.
- An immune response aimed at a single type of cancer cell can be stimulated by injecting antibodies that have already been activated with proteins from that tumor. The antibodies, will bind exclusively to the tumor cells inside the body that bear this protein, initiating an immune response against that tumor specifically. In people with cancer, the use of monoclonal antibodies improves survival and reduces the risk of recurrent cancer.
Immunotherapy has been shown to be a promising method for the treatment of certain malignant tumors including melanoma. It can effectively destroy tumor cells in the body. It can also considerably reduce the risk of recurrence of the disease.