Electrocautery Ablation for the Prevention of Lung Cancer

Inclusion criteria: 1. Patients with ≥1 airway HGL (defined as severe dysplasia or carcinoma in situ on histology) PRE-REGISTRATION Patient has a high likelihood of having airway HGLs as evaluated by investigator: * patient already part of existing surveillance programme or * HGL identified at other hospital and patient is referred to study site or * patient has abnormal sputa and patient is referred to study site PRE-RANDOMISATION Following registration, patients undergo a baseline bronchoscopy and only those with ≥1 airway HGL(s) can continue to randomisation provided they continue to meet all the inclusion/exclusion criteria below 2. Absence of primary lung cancer as confirmed by CT thorax OR recent surgical removal of a lung cancer with clear resection margins (of cancer) confirmed OR recent successful curative SABR treatment, as confirmed by MDT 3. Male or female patients ≥18 years of age 4. No upper age limit but life expectancy thought to be at least 3 years (in the opinion of the treating clinician) 5. ECOG Performance Score 0-2 6. FEV1 ≥ 25% of predicted\* 7. DLCO/TLCO ≥ 20% of predicted (only required for registration)\* 8. Patients who are women of child-bearing potential (WOCBP) must also have a negative pregnancy test at the following time points: * One pregnancy test prior to registration * One pregnancy test within 24 hours prior to the 1st EC treatment within each EC treatment round 9. Consent to donation of biological samples for translational work. Patients will be deemed ineligible if they do not consent to donate translational samples 10. Patient is willing and able to comply to protocol procedures and attend all study visits including all bronchoscopy and EC treatment visits. * if spirometry is not possible (e.g. due to COVID-19) investigator assessment that the patient is sufficiently fit for bronchoscopy and EC treatment is permissible. Exclusion criteria: 1. Finding of (micro)-invasive disease on histology (assessed at randomisation) 2. Patients who have one or more HGL present for ≥5 years which have remained persistent on white light or autofluorescence bronchoscopy (AFB) surveillance 3. Detection of active cancer or on systemic treatment for cancer, excluding basal cell skin cancers 4. Previous radiotherapy to the treatment area 5. ECOG Performance Score \>2 6. Patients who have one or more HGL greater than 3cm in length 7. Patients with a history of pulmonary hypertension 8. Patients who are anticoagulated for prosthetic heart valves 9. Decompensated heart disease with life expectancy less than 3 years 10. Severe liver and renal insufficiency with life expectancy less than 3 years 11. Patient unlikely to cooperate with a 3-year follow-up; medical or psychological condition at the discretion of the investigator which would not permit compliance with the protocol or meaningful signed informed consent 12. Participation in another study with an investigational medicinal product within one month prior to registration 13. Pregnant patients (confirmed by serum/urine ß-HCG) 14. Any other known condition which is assessed as an intolerable risk by the investigator upon inclusion in the study