Combination of Immunotherapy and Radiation Therapy in Gastrointestinal Cancers: An Appraisal of the Current Literature and Ongoing Research

Abstract

Oncological outcomes are improving in gastrointestinal cancer with advancements in systemic therapies, and there is notable potential in combining immunotherapy and radiation therapy (RT) to allow for further improvements. Various preclinical and early phase II studies have shown promising synergy with immunotherapy and RT in gastrointestinal cancer. A few recent phase III studies have shown improved survival with the addition of immunotherapy to standard treatment for gastrointestinal cancer. The timing, duration, sequencing, and integration with other anti-cancer treatments are still areas of ongoing research. We have reviewed the published and ongoing studies of the combinations of immunotherapy and RT in gastrointestinal cancers.

Keywords: PD L1; immune checkpoint inhibitors; immunotherapy; radiation.

Figure 1

Pre-treatment (a,b) and post-treatment (c,d) PET images of a patient with cT2N1 adenocarcinoma of the lower esophagus with PDL1 30% (white arrow shows the site of esophageal disease, with the insert showing the magnified image). Patients received neoadjuvant chemoradiation (Carboplatin/Paclitaxel/RT) with concurrent nivolumab in view of high PDL1. Esophagectomy showed complete response in esophageal primary and nodes.