Certain cancer treatments (such as chemotherapy, radiation therapy, surgery, stem cell or bone marrow transplant, or steroids) or cancer itself can suppress or weaken the immune system. These treatments can reduce the number of white blood cells (WBC) and other immune system cells. Radiation damages the genetic material of cells. This kills both cancer cells and those of the immune system.
The effects tend to be smaller than with chemotherapy. Radiation can directly damage the immune system, or it can cause other conditions that impair immunity. Much of this depends on where the cancer is. Survivors of Hodgkin lymphoma, especially those diagnosed before 1988, had their spleen removed.
The spleen is a vital organ for the immune system. Removing it is linked to an increased risk of infections. Chemotherapy and radiation therapy to the chest can damage the lungs. Cancer survivors who received chemotherapy and radiation therapy may have a higher risk of lung damage.
People who have had lung disease and older adults may have more lung problems. Even so, there are reasons why your immune system may weaken. One is that people tend to take newer immunotherapy drugs after other options failed. Such treatments, such as chemotherapy and radiation, are known to lower the immune response.
The effects of radiation on the tumor microenvironment and immune system can be modified by the radiation dose and the dose administration methods used. Therefore, the association between radiation and immunotherapy depends entirely on the dose and fraction of radiation involved. In a human in vitro model, HMGB1 levels in different human cancer cell lines were increased by carbon ion radiation. Local radiation therapy for breast cancer, which treats the area where the cancer was found, usually doesn't have a major impact on the immune system.
The interaction of new radiation therapy technologies with newly developed targeted agents are promising strategies for cancer treatment. It can occur as a late effect of previous cancer treatments, such as chemotherapy and radiation therapy.