'SOURCE - LUNG' Stereotactic Ablative Radiation Therapy Of UltRaCEntral LUNG Tumours (SOURCE Lung)

The rate of ≥ Grade 3 treatment-related toxicities occurring between start of treatment and one-year from the end of treatment using NCI CTCAE V5

The rates of ≥ Grade 3 treatment-related adverse events (TxR-AEs) will be calculated as the proportion of evaluable patients (along with the 95% CI) who have any \>= Grade 3 treatment-related adverse event occurring between the start of RT and one year post-RT, among the total evaluable patients. These rates will be reported (for applicable patients) by T stage (T1 versus T2 versus T3 versus T4 or combined T stages). The NCI Common Terminology Criteria for Adverse Events (CTCAE Version 5.0) for scoring the treatment-related adverse events will be used. The following will be reported at the time of primary endpoint analysis * Tabulation of all cases entered, and any patients excluded from the analysis with reasons for exclusion; * Distribution of important prognostic baseline and other pre-treatment variables; * Frequency and severity of adverse events; * Compliance rates of treatment delivery with respect to the protocol prescription

Estimate time to locoregional recurrence/progression, locoregional recurrence-free survival (LRFS), disease-free survival (DFS) and metastasis-free survival rates / further metastasis-free survival rates (for patients with an oligometastatic lesion).

The Kaplan-Meier method will be used to estimate time to locoregional recurrence; the cumulative proportion surviving without local recurrence at 1- year, 3-years and 5-years; DFS; metastasis-free survival for patients with primary NSCLC; further metastasis-free survival for patients with an oligometastatic lesion. These efficacy endpoints will be expressed as median survival with 95% confidence interval.

Estimates of 1-year, 3-year and 5-year overall survival rates

The Kaplan-Meier method will be used to estimate time the cumulative proportion surviving (overall survival) at 1-year, 3-years and 5-years. Overall survival will be measured from date of registration/ enrolment. Patients alive and free of event at the time of analysis and patients lost to follow-up will be censored at the last available assessment. The event for overall survival is a death due to any cause. The primary time-point of interest is 12 months.

Post treatment response and outcomes using PET and CT at 3, 6, 9, 12,18, 24, 36, 48 and 60 months post-RT

Only patients who received the prescribed RT dose and who are alive at the specified CT TA timepoints during follow up will be evaluated for tumour response and included in the analysis of tumour response rates. Whole body FDG-PET-CT scan will be done within 18 weeks prior to registration (may be conducted 18-22 weeks prior to registration for some patients, if the patient has had a CT TA within 18 weeks prior to registration), at 6 months and as clinically indicated post-SABR based on review of CT-TA scans.

Acute toxicity profiles on treatment to 3 months post treatment

Acute toxicity rates will be calculated, summarised and presented in tabular format with proportions plus 95% confidence intervals where appropriate.

Late toxicity profiles to 5 years post treatment

Late toxicity rates will be calculated, summarised and presented in tabular format with proportions plus 95% confidence intervals where appropriate.

Time to onset of acute and late ≥ Grade 2 and ≥ Grade 3 toxicities

Time to event will be measured for toxicities (which are related to trial treatment) from treatment start date. Patients alive and free of event at the time of analysis and patients lost to follow-up will be censored at the last available assessment. The primary time-point of interest is 12 months.