Immunotherapy, also called biological therapy, or the use of biological response modifiers (BRMs), is the main approach to treating metastatic kidney cancer. Immunotherapy uses substances produced by the body to stimulate the immune system so that white blood cells will attack and kill cancer cells.
Many types of white blood cells help fight RCC, including natural killer cells, T cells called CD8 cells and CD4 cells, antigen-processing cells and tumor infiltrating lymphocytes. These can also be produced in a laboratory.
Cytokines, proteins that activate the immune system to shrink tumors, have become a standard immunotherapy. Cytokines such as interleukin-2 (IL-2) and interferon-alpha have been shown to reduce about 20 percent of kidney tumors to less than half their original size. Studies also suggest that people treated with IL-2 may have longer-lasting responses to treatment. A low-dose combination of these two cytokines seems as effective as high dose IL-2 and has fewer and less severe side effects.
Studies of IL-2, interferon and the chemotherapy drug 5-fluorouracil (5-FU) are currently underway.
The side effects of cytokine therapy include kidney damage, fluid in the lungs, low blood pressure, heart attacks, intestinal bleeding, chills and high fever. Because of these severe side effects, only doctors experienced with this therapy should use it to treat RCC. Doctors may also activate immune system cells by removing them from the patient's blood, treating them with cytokines and then returning these cells to the blood stream.
These cells then seek out and attack the kidney cancer cells. RCC growths already contain immune-system cells, tumor infiltrating lymphocytes (TILs), that fight cancer cells. Studies show that cytokine-activated TILs may be more effective than cytokine-activated immune cells from the bloodstream.
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