Objectives: Thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) are commonly used in the management of extensive-stage small-cell lung cancer (ES-SCLC); however, Phase III trials of first-line immunotherapy often excluded these options. Guidance is needed regarding appropriate use of TRT, PCI, and magnetic resonance imaging (MRI) surveillance while new data are awaited., Materials and Methods: In two web-based meetings, a pan-Canadian expert working group of five radiation oncologists and four medical oncologists addressed eight clinical questions regarding use of radiation therapy (RT) and MRI surveillance among patients with ES-SCLC receiving immunotherapy. A targeted literature review was conducted using PubMed and conference proceedings to identify recent (January 2019-April 2022) publications in this setting. Fifteen recommendations were developed; online voting was conducted to gauge agreement with each recommendation., Results: After considering recently available evidence across lung cancer populations and clinical experience, the experts recommended that all patients with a response to chemo-immunotherapy, good performance status (PS), and limited metastases be considered for consolidation TRT (e.g., 30 Gy in 10 fractions). When considered appropriate after multidisciplinary team discussion, TRT can be initiated during maintenance immunotherapy. All patients who respond to concurrent chemo-immunotherapy should undergo restaging with brain MRI to guide decision-making regarding PCI versus MRI surveillance alone. MRI surveillance should be conducted for two years after response to initial therapy. PCI (e.g., 25 Gy in 10 fractions or 20 Gy in 5 fractions) can be considered for patients without central nervous system involvement who have a response to chemo-immunotherapy and good PS. Concurrent treatment with PCI and immunotherapy or with TRT, PCI, and immunotherapy is appropriate after completion of initial therapy. All recommendations were agreed upon unanimously., Conclusions: These consensus recommendations provide practical guidance regarding appropriate use of RT and immunotherapy in ES-SCLC while awaiting new clinical trial data., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: A. Sun has received honoraria from and participated in advisory boards with AstraZeneca. B. Abdulkarim has no conflicts to disclose. N. Blais reports receiving consulting fees from AstraZeneca. J. Greenland has received honoraria from AstraZeneca for attendance at advisory boards. A.V. Louie reports receiving honoraria from AstraZeneca for a speakers bureau and an advisory board. B. Melosky has received honoraria from AstraZeneca, BMS, Merck, and Roche. D. Schellenberg reports receiving institutional grants from Varian Medical Systems and payments from AstraZeneca, Merck, and Pfizer for presentations/educational events and advisory board participation. He also reports participation in Linear Accelerator selection for BC Cancer and receipt of a class action lawsuit payment from Medtronic. S. Snow reports research/trial funding paid to her institution by AstraZeneca, BMS, Merck, Novartis, Sanofi, and Takeda and receiving consulting fees from Novartis and Roche. She has also received honoraria for lectures and presentations at educational events from Amgen, AstraZeneca, Bayer, BMS, Elvium Life Sciences, Jazz Pharmaceuticals, Pfizer, and Taiho. S. Snow has also participated in advisory boards for Amgen, Astellas, AstraZeneca, Bayer, BeiGene, BMS, EMD Serono, Janssen, Jazz Pharmaceuticals, Merck, MSD, Novartis, Pfizer, Roche, Sanofi, Takeda, and Taiho, and was the President of Lung Cancer Canada and on its Board of Directors at the time of publication. G. Liu has received institutional research grants from NCI (US), CIHR (Canada), CCSRI (Canada), Amgen, AstraZeneca, Boehringer Ingelheim, and Takeda. He has received payment or honoraria from AstraZeneca, EMD Serono, Jazz Pharmaceuticals, Novartis, Pfizer, and Takeda, and has participated in data safety monitoring boards or advisory boards with AbbVie, AstraZeneca, BMS, EMD Serono, Jazz Pharmaceuticals, Eli Lilly, Merck, Novartis, Pfizer, Roche, and Takeda., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)