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Radiotherapy May Boost Effectiveness of Immune-Targeting Cancer Therapies

Early studies of combining radiotherapy and checkpoint inhibitors show some promise against several cancers.

Jill Sakai, Contributor
Monday, May 14, 2018


Immune checkpoint-inhibiting drugs block the immune pathways that many cancers use to evade the body’s protective mechanisms. Although these drugs show promising clinical results against multiple tumor types, many patients still experience suboptimal responses or relapse after treatment. Researchers are exploring the potential benefit of adding radiation therapy to help combat tumors by boosting the effects of immune-targeting cancer treatments.

As described in a review published April 11 in Therapeutic Advances in Medical Oncology, three small clinical trials recently evaluated the combination of radiotherapy and immune checkpoint inhibitors in a total of 79 patients with metastatic melanoma or other advanced cancers. The combination did not increase the occurrence of serious side effects, and patient response rates to the combined treatment were similar or slightly better than those reported by large trials using immunotherapy alone. In addition, the patients who showed good clinical responses to the combination also showed biomarker changes consistent with immune system activation.

The authors suggest that adding radiotherapy to immune checkpoint inhibitors may be a promising approach to improve cancer treatment. However, more comprehensive trials are needed to help answer questions such as how to identify the patients most likely to benefit from a combination treatment, or how to determine appropriate dosing and whether the treatments are best administered simultaneously or sequentially. Some of these factors are likely to vary between cancer types, the authors note.

The authors suggest that combination treatments might help patients combat cancers even more effectively during earlier disease stages and reduce the chance of metastasis.