Immunotherapy and Cancer Immunotherapy
Immunity is very important to our bodies, otherwise we would quickly be defeated by colonies of microorganisms and the negative impact of diseased or damaged cells in our own bodies. The immune system protects us from these influences and enables us to live in a non-sterile world.
If the immune system succumbs to the negative factors, we fall ill. Nowadays, many diseases are solved by medications; we rely on them as a “quick fix”. By this we are not doing any favour to our bodies.
Immunotherapy is not a new method of treatment. It first appeared in 1960s; however, it was not as successful as expected. It was rediscovered later on with some new findings in the field of immunology, and the opportunity of using the immune system to fight cancer has risen. Under normal circumstances, the immune system gives no chance to cancer to develop, and so it may significantly contribute to its treatment.
Cancer immunotherapy aims to detect cancer cells and “break release” the immune system which activates and multiplies defence cells to subsequently eliminate tumour or metastases. The onset of the treatment’s effects is very slow compared to chemotherapy; it often takes several months to activate immunity (3-5 months). However, its great advantage includes low side effects and ability of the immune system to adapt to tumour mutations even during remission. In the future this intervention should play an increasingly important role in cancer treatments. Although it is not appropriate for all cancer patients, as it is sometimes difficult to predict a treatment response, immunotherapy is given if other methods have failed – especially in chemoresistant tumours (tumours resisting chemotherapy). A limiting factor in the use of immunotherapy is associated with autoimmune diseases – rheumatoid arthritis, multiple sclerosis or Crohn’s disease.
Current cancer immunotherapy has been approved for skin melanoma and prostate cancer, its effectiveness for other types of cancer is under investigations. It may be combined with the standard treatment (surgical removal, chemotherapy, radiotherapy) to promote body’s defence mechanisms and to aid combating the disease more effectively.
Immunotherapy may be applied in 2 ways:
- Active cancer immunotherapy is based on the administration of a cancer vaccine which induces an immune response to cancer antigens. Because cancer cells arise from healthy cells, their antigens (foreign substances on a cell surface stimulating antibody production or another immune response) are difficult to distinguish. Each tumour has a different antigen set, and each body reacts differently, thus one universal anti-cancer vaccine is out of question.
- Therefore passive support is becoming more popular. It is based on administration of ready-made antibodies; most often they are monoclonal vaccines or activated white blood cells.
Therapy is rather costly and its primary use for cancer remains a subject of discussions. Typically, therapy lasts 9 weeks and the drug is applied intravenously 4x with 3-week intervals. Even today cancer immunotherapy exceeds the long appraised effects of chemotherapy in some types of cancers (malignant melanoma). Results of many studies suggest its use in the future is very promising to treat many cancer types.