Cancer treatments, such as chemotherapy, radiation therapy, surgery, stem cell or bone marrow transplant, or steroids, can have a significant impact on the immune system. Radiation therapy is known to damage the genetic material of cells, leading to the death of both cancer cells and those of the immune system. The effects of radiation on the immune system are usually smaller than those of chemotherapy. The location of the cancer can also affect the immune system.
For example, survivors of Hodgkin lymphoma who were diagnosed before 1988 often had their spleen removed. The spleen is an important organ for the immune system, and its removal can increase the risk of infections. Additionally, chemotherapy and radiation therapy to the chest can damage the lungs, leading to an increased risk of lung problems for cancer survivors. Immunotherapy drugs are often taken after other treatments have failed.
These treatments can lower the immune response. The effects of radiation on the tumor microenvironment and immune system can be modified by the radiation dose and dose administration methods used. In a human in vitro model, carbon ion radiation was found to increase HMGB1 levels in different human cancer cell lines. Local radiation therapy for breast cancer usually does not have a major impact on the immune system. The interaction between new radiation therapy technologies and targeted agents is a promising strategy for cancer treatment.
However, weakened immunity can also occur as a late effect of previous cancer treatments such as chemotherapy and radiation therapy.