Beyond Abscopal Effect: A Meta-Analysis of Immune Checkpoint Inhibitors and Radiotherapy in Advanced Non-Small Cell Lung Cancer

• Main Authors: Francesco Fiorica, Umberto Tebano, Milena Gabbani, Mariasole Perrone, Sonia Missiroli, Massimiliano Berretta, Jacopo Giuliani, Andrea Bonetti, Andrea Remo, Eva Pigozzi, Andrea Tontini, Giuseppe Napoli, Nicoletta Luca, Daniela Grigolato, Paolo Pinton, Carlotta Giorgi
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Cancers
• Subjects: combination of immune checkpoint inhibitors and radiotherapy; radiation oncology and immunity; radiation oncology; immunotherapy
• Online Access: https://www.mdpi.com/2072-6694/13/10/2352

Background: Immune checkpoint inhibitors (ICI) plus radiotherapy (RT) have been suggested as an emerging combination in non-small cell lung cancer (NSCLC) patients. However, little is known about the magnitude of its benefits and potential clinical predictors. Objective: To assess the effects of this combination on the increase in overall and progression-free survival. Data sources: The MEDLINE and CANCERLIT (1970–2020) electronic databases were searched, and the reference lists of included studies were manually searched. Study selection: Studies were included if they were comparative studies between combination ICI-RT and ICI or RT alone in advanced or metastatic NSCLC patients. Overall survival (OS) was analyzed according to the treatment strategy. Data extraction: Data on population, intervention, and outcomes were extracted from each study, in accordance with the intention-to-treat method, by two independent observers and combined using the DerSimonian method and Laird method. Results: Compared to ICI or RT alone, ICI-RT significantly increased the 1-year and 3-year OS RR by 0.75 (95% CI 0.64–0.88; <i>p</i> = 0.0003) and 0.85 (95% CI 0.78–0.93; <i>p</i> = 0.0006), respectively. Furthermore, there was a statistically significant benefit on 1- and 3-year progression-free survival (RR 0.73 (95% CI, 0.61–0.87; <i>p</i> = 0.0005) and RR 0.82 (95% CI 0.67–0.99; <i>p</i> = 0.04), respectively). Conclusions: In patients with advanced or metastatic NSCLC, combination ICI-RT increases 1- and 3-year OS and progression-free survival compared to ICI or RT alone.