Inclusion Criteria:

- Written Informed consent

- Patients >18 years of age, with early stage I-IIIA disease who are eligible for
primary surgery

- Primary surgery in keeping with NICE guidelines (lobectomy (either open or
thoracoscopic), lung parenchymal-sparing operations (segmentectomy or wedge
resection) if a complete resection can be achieved, extensive surgery
(bronchoangioplastic surgery, bilobectomy, pneumonectomy) if necessary to obtain
clear margins, hilar and mediastinal lymph node sampling or en bloc resection)

- Histopathologically confirmed NSCLC, or a strong suspicion of cancer on lung imaging
necessitating surgery (e.g. diagnosis determined from frozen section in theatre)

- Agreement to be followed up every 3 months in the first year and then 6 monthly for
cfDNA analysis and chest xray assessments for total 5 years.

- Agreement to be followed up in specialist centre

- Performance status 0 or 1

- Considered sufficiently fit for platinum/vinorelbine adjuvant therapy if indicated
(cisplatin or carboplatin allowed)

Exclusion Criteria:

- Any other current malignancy or malignancy diagnosed or relapsed within the past five
5 years (other than non-melanomatous skin cancer and in situ cervical cancer)

- Psychological condition that would preclude informed consent

- Adjuvant regimen other than platinum/vinorelbine

- Women who are pregnant or lactating