A 52-year-old man with a 30-pack-year smoking history presents with persistent cough and haemoptysis for 3 weeks. Chest X-ray shows a left lower lobe opacity. Bronchoscopy reveals a nodular lesion in the left lower lobe bronchus, and multiple biopsies are taken. Histopathology shows intestinal-type metaplasia of the bronchial epithelium with focal areas of dysplasia (CIN 2). The patient is asymptomatic apart from cough and has no dyspnoea or stridor. What is the most appropriate next step in management?