Radiotherapy changes the behavior of immune cells. In a study on mice, researchers were able to reprogram them to improve the effectiveness of treatment and, consequently, the survival rate.
Cancer can be treated with different methods, some of which have a cumulative effect. In most cases, the tumor is first removed surgically and the patient then undergoes radiation and/or chemotherapy. Other types of cancer are treated with so-called targeted therapies, which target only specific cells, or with immunotherapy or hormone therapy. All these treatment techniques can have side effects. For example, radiotherapy for brain tumors can interfere with immune cells called macrophages. In Science Translational Medicine, researchers at the Ludwig Institute for Cancer Research explain that administering a certain drug in addition to radiotherapy prevents such symptoms.
Positive results, but dangerous side effects
Scientists have discovered that radiotherapy alters the genetic expression of macrophages in two types of tumors. This transformation leads to increased resistance to therapy and the potential growth of tumors. “Radiation naturally destroys many cancer cells,” says Johanna Joyce, co-author of the study, “but it has also caused all these macrophages to rush into the tumor to clean up the mess and, as a consequence, they’ve been super-activated to create a permissive niche for the remaining cancer cells to form new tumors.”
Could Extend Life
She and her team administered a drug called factor-1 receptor inhibitor (FCR-1R) to mice suffering from glioblastoma, a form of brain tumor. According to her findings, this prevented macrophages from transforming and allowed the animals to survive longer. “About 95 percent of the mice survived the full six months of the study,” she added. Two regimens of administration were studied: The first was to administer the drug for 12 days. It extended the average life of the mice by three weeks, compared with those treated with radiotherapy alone. When the inhibitor was administered to the mice for several months, the results were even more impressive, with a longer survival time for the rodents.
A rare disease
According to the American Cancer Society, there are 23,890 new cases of brain and spinal tumors in the US every year. This type of cancer affects both adults and children and the chance that a person will develop a tumor of the brain or spinal cord in his or her lifetime is inferior to 1%.