Immune system: The most important facts about the new immunotherapy
How does the human immune system react to developing tumors? And what is the new immune therapy against cancer all about?
Everyone is talking about it: immunotherapy against cancer. In 2018, the researchers who discovered the basis for it were awarded the Nobel Prize and new drugs are currently being used. The therapy raises many questions and high hopes. Oncologist Dr. Albrecht Kretzschmar from the Centre for Integrative Oncology ZIO in Glarus, says: "Immuno-oncological therapy often works very well for certain types of cancer. Unfortunately, it doesn't work for others." For melanoma and other types of skin cancer, for example, the therapy is often effective. In most cases of breast or bowel cancer, however, it is ineffective.
"This is because the development of skin cancer leads to a large number of mutations in the cells and the immune system can therefore recognize the cancer cells relatively well. This is not the case with other types of cancer such as bowel cancer," says Kretzschmar.
How the immune system reacts to cancer cells
The crucial point is where the immune system recognizes a cancer cell - or not. "Our immune system can theoretically recognize and fight things that don't belong to our body. To prevent the immune system from attacking the body's own cells and thus triggering autoimmune diseases, there is a kind of 'brake' that kicks in when necessary and weakens the immune response," explains Kretzschmar. The problem with cancer is that the tumors develop from the body's own cells. This is why the "brake" works here and the immune system does not react at first.
In certain types of cancer, there are many mutations during tumor growth so that the cancer cells become less and less like the body's own cells over time. - This is a good prerequisite for immune cells to become effective. If the "brake" described above is released with the drugs used in immuno-oncological therapy, the cancer cells may be destroyed permanently.
The therapy therefore works well for cancers with many mutations, although not for everyone, as not every body reacts to therapy in the same way. However, if immuno-oncology therapy works, it usually helps for a very long time - sometimes even permanently. "This is also the reason why the therapy is so promising," says oncologist Kretzschmar.
"Sometimes the therapy works quite well on its own. Sometimes it works particularly well in combination with chemotherapy or other targeted therapy."
Hardly effective for breast and colorectal cancer
However, according to current findings, immuno-oncology therapy has little effect on cancers that cause fewer mutations. "The effect on breast and bowel cancer has already been relatively well studied, but unfortunately this therapy is of little use there. Further studies are still ongoing for other types of cancer," says Kretzschmar.
Of course, the oncologist emphasizes that immuno-oncology therapy is not always without side effects. "Many patients tolerate the therapy very well and hardly experience any side effects. Compared to chemotherapy, side effects even occur rather rarely," says Kretzschmar. However, there is a risk of acquiring an autoimmune disease, which is why Kretzschmar strongly encourages patients to contact their treating physicians if they notice anything unusual.
You can find out more about chemotherapy and the immune system here.
