This research project is testing a new treatment planning method for patients with lung cancer who will be treated with radiation therapy. This new method is called Computed Tomography (CT) ventilation imaging. It aims to help protect the healthiest parts of patient's lungs from being injured by the radiation therapy. The investigators will determine whether healthy lung sparing can improve the quality of life in these patients.

The planning and delivery of Radiation Therapy (RT) is a balance between delivering a curative dose to the tumour while sparing healthy organs, such as the lungs, from collateral damage such as pneumonitis. To minimise radiation-induced lung injury, our team has invented and pioneered ventilation imaging based on Computed Tomography (CT). This Australian-invented medical device, now an international field of research, uses CT scans routinely acquired for planning RT to compute a CT ventilation map showing high functioning and low functioning lung regions. This image is used as the basis for directing radiation away from the healthy, high functioning regions towards the low functioning regions, thereby aiming to reduce toxicity and improve the patient's quality of life.

Inclusion Criteria

1. Aged 18 years or older.
2. Eastern Cooperative Oncology Group (ECOG) performance status 0-2.
3. Histologically proven non-small cell lung cancer.
4. Stage 3 as determined using the IASLC (International Association for the Study of Lung Cancer) 8th edition lung cancer staging guidelines.
5. To be treated with curative intent external beam radiotherapy (60 Gy in 30 treatments or 55 Gy in 20 treatments) +/- concurrent chemotherapy and adjuvant PD1/PD-L1 inhibitors.
6. Whole body Positron Emission Tomography (PET) scan within 8 weeks of registration.
7. Pulmonary function tests within 8 weeks of registration.
8. Willingness to give written informed consent.
9. Willingness to comply with the study procedures and visit requirements.
10. Available for follow up for a minimum of 12 months and up to 3 years.

Post-inclusion criteria includes the results of a Quality of Life (QoL) assessment and treatment plan assessment, neither of which are known prior to consent. The post-inclusion criteria for the VITaL trial are:

1. Functional Assessment of Cancer Therapy - Lung (FACT-L) Trial Outcome Index (TOI) score of ≥5, the clinically meaningful difference
2. The standard treatment plan shows that at least 16% of volume of the lungs (minus the Gross Tumour Volume (GTV)) will receive more than 20 Gy. This criterion is based on the difference in pneumonitis risk between patients receiving below (~8%) and above (~34%) this threshold.

The QoL assessment is unlikely to eliminate any patients but is included for patients where no clinically meaningful difference will be possible. The treatment plan assessment may exclude 20% of otherwise eligible patients.

Exclusion Criteria:

1. Serious medical comorbidities that may contraindicate curative radiotherapy.
2. Inability to attend full course of radiotherapy or follow-up visits.
3. A current or former diagnosis of interstitial lung disease.
4. Prior history of lung cancer within 5 years.
5. Prior thoracic radiotherapy at any time.
6. Prior surgery for this cancer within a year.
7. Prior chemotherapy for this cancer.
8. Pregnant or lactating women.

After study findings have been published, un-identifiable (non-coded, completely de-identified) data will be shared with researchers or at an external data repository for further scientific research.

Data will be made available following the publication of the final results.

Data will only be shared with repositories whose function has been reviewed and approved by an accredited Research Integrity/Ethics Committee/Board, under a Materials Transfer Agreement with the University of Sydney.