12-month progression free survival was determined for each subject as a binary variable indicating whether or not the subject was progression free and surviving at 12 months after study enrollment. Failure occurred if the subject progressed or died from any cause within 12 months of study enrollment. Disease progression was determined according to RECIST v1.1.

The population evaluable for the 12-month PFS outcome is defined as all subjects who initiate treatment with SBRT and experienced a PFS event within 12 months of enrollment or have at least one year of radiologic follow-up from enrollment.

PFS is defined as the duration of time from treatment start date to first occurrence of either progressive disease (PD) or death. PD must be objectively determined per RECIST v1.1 criteria, where progression date is date of last radiologic assessment that identified PD. If subject died without documented PD, progression date will be death date. For surviving subjects who do not have PD, PFS will be censored at the date of last radiologic assessment. For subjects who received subsequent anti-cancer therapy prior to documented PD, PFS will be censored at the date of last radiologic assessment prior to commencement of subsequent therapy. Subjects who have an initial PFS event immediately following 2 or more consecutive missed assessments will be censored at date of last assessment prior to missed assessments.

OS is defined as the duration from enrollment to the study (treatment start date) to the date of death from any cause. Participants who are alive or lost to follow-up at the time of the analysis will be censored at the last known date they were alive.

Radiologic clinical complete response will be recorded for each subject as a binary variable indicating whether or not the subject had no evidence of disease on either PET/CT or CT scan approximately 3 months after the last treatment of concurrent mediastinal chemoradiation.

Defined as all subjects who initiate treatment with SBRT and who have PET/CT results at approximately 3 months after last treatment of concurrent mediastinal chemoradiation.

Objective response is determined for each participant as a binary variable indicating whether or not the participant achieved a best overall response of complete response (CR) or partial response (PR) as determined by RECIST v1.1 criteria.

The response evaluable population is defined as all subjects who initiate treatment with SBRT and who have measurable disease present at baseline.

Local control (LC) is defined as the duration of time from enrollment to the study to first progression of the subject's primary lesions(s). If a participant dies prior to local progression local control will be censored at the date of death. For surviving subjects with no documented local progression, local control will be censored at the date of the last radiologic assessment that evaluated the local tumor(s). For subjects who receive subsequent anticancer therapy prior to documented local progression, local control will be censored at the date of last radiologic assessment that evaluated the local tumor(s) prior to the commencement of subsequent therapy. Local control will be estimated at 12 and 24 months.

Regional control (RC) is defined as the duration of time from enrollment to the study to first progression of the subject's regional lesions(s). If a participant dies prior to regional progression regional control will be censored at the date of death. For surviving subjects with no documented regional progression, regional control will be censored at the date of the last radiologic assessment that evaluated the regional tumor(s). For subjects who receive subsequent anticancer therapy prior to documented regional progression, regional control will be censored at the date of last radiologic assessment that evaluated the regional tumor(s) prior to the commencement of subsequent therapy. Regional control will be estimated at 12 and 24 months.

Locoregional control is defined as the duration of time from enrollment to the study to first progression of the subject's local and/or regional lesions(s), whichever occurs first. If a participant dies prior to locoregional progression locoregional control will be censored at the date of death. For surviving subjects with no documented local and/or regional progression, locoregional control will be censored at the date of the last radiologic assessment that evaluated the local and regional lesion(s). For subjects who receive subsequent anticancer therapy prior to documented locoregional progression, locoregional control will be censored at the date of last radiologic assessment that evaluated the local and regional tumor(s) prior to the commencement of subsequent therapy. Locoregional control will be estimated at 12 and 24 months.

Distant control defined as the duration of time from enrollment to first metastatic progression. If a subject dies prior to metastatic progression, distant control will be censored at the date of death. For surviving subjects with no documented metastatic progression, distant control will be censored at the date of the last radiologic assessment. For subjects who receive subsequent anti-cancer therapy prior to documented metastatic progression, distant control will be censored at the date of last radiologic assessment prior to the commencement of subsequent therapy. Distant control will be estimated at 12 and 24 months.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. EORTC QLQ-C30 includes 5 functional scales, 9 symptom scales/items, and a global health status/quality of life (QoL) scale. The global health status/QoL score is determined from two 7-point items, ranging from 1 (Very Poor) to 7 (Excellent). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score represents a higher (better) quality of life.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

The EORTC QLQ-LC13 is a 13-item questionnaire to assess lung cancer associated symptoms, treatment related side effects and pain medication. Both multi-item and single-item measures of lung-cancer associated symptoms and side-effects from conventional chemo and radiotherapy. We focused on 3 symptoms of interest from the EORTC QLQ-LC13: dyspnoea, coughing, and dysphagia. Dyspnoea is a function of three items and can only be determined if all three items have been answered, while coughing and dysphagia are single-item symptoms. Each symptom score is determined by averaging the items that contribute to the scale to get a raw score. Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher symptom score represents a higher (worse) level of symptoms.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

The MDASI-LC Module includes 22 questions to assess the severity of multiple lung cancer-related symptoms and the impact of these symptoms on daily functioning. Scores for each item range from 0 to 10, where 0 indicates no symptoms and 10 indicates worst possible symptoms. Arithmetic mean of the items completed was calculated to determine a mean total symptom + interference score ranging from 0 to 10. The mean score is reported if more than 50% of the items are completed on a given administration. Higher scores indicate worse symptoms and more interference.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each subject indicating whether or not the subject experienced at least one grade 2 or higher pneumonitis adverse event according to the NCI Common Terminology for Adverse Events version 4.0 during induction. Pneumonitis events receiving treatment with steroids and possibly, probably, or definitely attributed to SBRT or mediastinal radiation will be included.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each subject indicating whether or not the subject experienced at least one grade 3 or higher pulmonary adverse event according to the NCI Common Terminology for Adverse Events version 4.0 during induction. This includes pulmonary adverse events regardless of attribution.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each participant indicating whether or not the subject had at least one adverse event that was categorized as serious, regardless of causality. Serious is defined per the study protocol and includes events that the investigator deems serious and results in the following outcomes: death, life-threatening situation, persistent or significant disability/incapacity, requires or prolongs hospitalization, congenital anomaly/birth defect in the offspring of a study participant, suspected transmission of any infections agent via medical product, or based upon medical judgement, may jeopardize the subject and may require medical or surgical intervention to prevent one of the afore listed outcomes from occurring.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each participant indicating whether or not the subject had at least one treatment-emergent adverse event, regardless of causality. Adverse events will be categorized per NCI Common Terminology for Adverse Events version 4.0. Treatment-emergent is defined per the study protocol and includes AEs that occur after treatment start that were not present at the time of treatment start or AEs that increase in severity after treatment start if the event was present at the time of treatment start.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each participant indicating whether or not the subject had at least one grade 3 or higher treatment-emergent adverse event, regardless of causality. Adverse events will be categorized per NCI Common Terminology for Adverse Events version 4.0. Treatment-emergent is defined per the study protocol and includes AEs that occur after treatment start that were not present at the time of treatment start or AEs that increase in severity after treatment start if the event was present at the time of treatment start.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each participant indicating whether or not the subject discontinued study treatment due to adverse events.

The evaluable population is defined as all subjects who initiate treatment with SBRT.

A binary variable will be determined for each participant indicating whether or not the subject received at least one dose of durvalumab on study

The evaluable population is defined as all subjects who initiate treatment with SBRT.