A pilot study of the combination of interleukin-2-based immunotherapy and radiation therapy

A clinical trial was undertaken to evaluate the feasibility of combining radiation therapy and immunotherapy. Twenty-eight patients with metastatic cancer were treated with rapid fractionation radiation up to 2,000 cGy, followed within 24 h by a course of interleukin 2 (IL-2) at 720,000 IU/kg or tumor-infiltrating lymphocytes (TILs) and IL-2 at 720,000 IU/kg. All patients tolerated treatment without any apparent increase in toxicity referable to the irradiation. Four patients had significant shrinkage of tumor at the irradiated site. Only two patients showed significant tumor shrinkage both inside and outside of the irradiated field. While rapid fractionation radiation can be safely administered in combination with immunotherapy, we observed no apparent synergy in antitumor effect in this small number of patients.