Experts from the Department of Radiation Oncology and Molecular Radiation Sciences are expanding evidence that shows targeted radiation stimulates an immune response against cancer.

As cancer cells are destroyed by radiation, they release their proteins into the bloodstream, clearly revealing their identities as cancer cells and, as a result, attracting the attention of the immune system. Conversely, however, there is growing proof that limiting radiation therapy to certain areas may also benefit the immune response to cancer.

Radiation oncology resident Ariel Marciscano, M.D., is collaborating with experts in the Bloomberg~Kimmel Institute for Cancer Immunotherapy to study how best to treat lymph nodes surrounding tumors that potentially may harbor hidden cancer cells. Radiation therapy is typically administered to these lymph nodes, but Marciscano has found it may destroy certain white blood cells that live in the lymph nodes and are critical to the immune response.

Using the small animal radiation research platform (SARRP), invented by radiation physicist John Wong, Ph.D., Marciscano compared mouse models radiating only the tumor to models radiating the tumor and lymph nodes. His findings, featured at the annual meeting of American Society for Radiation Oncology, showed that treatment of the lymph nodes might hinder the immune response to cancer. Marciscano’s research, made possible by the SAARP technology, is the first of its kind and indicates a need to shift the treatment paradigm when radiation therapy is combined with immunotherapies. Learning how to administer and sequence combined treatments involving immunotherapies is critical to their effectiveness, and this study provides vital new information essential to advancing emerging immune-targeted therapies.