Immunotherapy With Radiation Shows Efficacy Against Melanoma

New generation immunotherapies in combination with radiation treatments showed promise against melanoma during a recent trial.

According to the American Cancer Society, 76,000 people in the United States will be diagnosed with melanoma this year, while 10,000 people are expected to die from the disease.

Typically, radiation works by damaging cancer cell DNA, causing death. Meanwhile, immunotherapies harness a patient’s own immune system to attack and kill cancer cells.

An article published in the Journal of Radiation Oncology found that when the 2 therapies are combined, a synergistic effect seems to take place.

During rare occurrences, patients can spontaneously go into remission, but more common is partial spontaneous regressions of melanoma lesions. Researchers believe that the immune system starting an attack on cancer cells could have something to do with this, but the exact causes are still uncertain.

A key finding that supports the immune system’s role in melanoma is the abscopal effect, which is a rare phenomenon that takes place when a localized treatment, such as radiation, shrinks the tumor while also stimulating the immune system to start a systemic attack on cancerous cells.

Study author James S. Welsh, MD, was able to see this effect while treating a melanoma patient with radiation. The cancer had spread to the patient’s liver and bones, and the goal of the treatment was to decrease the tumors in the patient’s thigh bone; however, after 3 months, a CT scan could not find any traces of the cancer.

Currently, other new melanoma immunotherapies are being used, with one involving a new generation of checkpoint inhibitors. The drugs are able to disable the “brakes” that stop the immune system from attacking cancer cells.

Furthermore, there has been an increase in the use of radiation therapy along with checkpoint inhibitors and other immunotherapies that have shown promising results. Although the combination of immunotherapy and radiation show promise, there are still some patients unable to start an effective immune response against melanoma.

Researchers stress the importance of discovering proteins and other biomarkers that are able to predict whether or not a patient will respond to immunotherapy.