TRAcking Non-small Cell Lung Cancer Evolution Through Therapy (Rx)

Inclusion Criteria: * Written Informed consent * Patients ≥18 years of age, with early stage IIA-IIIB disease (according to TNM 8th edition) who are eligible for primary surgery. Patients with a radiological staging of IB (N0) who could be upstaged to IIA-IIIB following surgery (due to the presence of possible nodal involvement on the pre-operative scan) may also be included, but will be withdrawn if post-surgical staging remains IB. Histopathologically confirmed NSCLC, or a strong suspicion of cancer on lung imaging necessitating surgery (e.g. diagnosis determined from frozen section in theatre) * Primary surgery in keeping with NICE guidelines planned (see section 9.3) * Agreement to be followed up at a TRACERx site * Performance status 0 or 1 * Minimum tumour diameter at least 15mm to allow for sampling of at least two tumour regions (if 15mm, a high likelihood of nodal involvement on pre-operative imaging required to meet eligibility according to stage, i.e. T1N1-3) Exclusion Criteria: * Any other\* malignancy diagnosed or relapsed at any time, which is currently being treated (including by hormonal therapy). * Any other\* current malignancy or malignancy diagnosed or relapsed within the past 3 years\*\*. \*Exceptions are: non-melanomatous skin cancer, stage 0 melanoma in situ, and in situ cervical cancer \*\*An exception will be made for malignancies diagnosed or relapsed more than 2, but less than 3, years ago only if a pre-operative biopsy of the lung lesion has confirmed a diagnosis of NSCLC. * Psychological condition that would preclude informed consent * Treatment with neo-adjuvant therapy for current lung malignancy deemed necessary * Post-surgery staging is not IIA-IIIB * Known Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) or syphilis infection. * Sufficient tissue, i.e. a minimum of two tumour regions, is unlikely to be obtained for the study based on pre-operative imaging