Lung Cancer — Written Clinical Reasoning

Model answer — Part A: the 15 mm spiculated nodule

Frame the problem first. A 15 mm spiculated solid nodule in an older heavy smoker is malignant until proven otherwise — this is a probability problem, not a surveillance problem. My assessment has three aims: estimate malignancy probability, obtain tissue safely, and stage as I diagnose ^{[1] [2]}.

Assessment. History: smoking exposure and quit date, weight loss, haemoptysis, prior malignancy, occupational exposures, family history, and cardiorespiratory fitness that will shape any curative option. Examination: clubbing, supraclavicular nodes, chest signs. I hunt for prior imaging of any kind — a nodule stable for 2 years changes the whole pathway ^[1].

Risk estimation. I would quantify risk rather than gesture at it: the Brock (PanCan) model combines age, sex, family history, emphysema with nodule size, spiculation, upper-lobe location, type and count. A 15 mm spiculated upper-lobe nodule in this man sits in a high-probability band — which means I move toward tissue, not toward interval scanning ^[2].

Investigation sequence. Dedicated thin-slice CT chest if the abdominal CT is technically limited; PET/CT to characterise metabolic activity, detect nodal and distant disease and direct the biopsy target; then tissue by the route that answers diagnosis and staging together — EBUS-TBNA if nodes are involved, CT-guided biopsy for the peripheral nodule itself. For a nodule above 8 mm at high risk, Fleischner supports PET/CT or tissue sampling, not surveillance ^{[1] [3]}.

Close the loop. Referral to the lung-cancer multidisciplinary meeting with pulmonary function tests if resection is plausible, an honest conversation with the patient about what we suspect and why each step exists, and smoking-cessation support started now — it improves every downstream outcome ^[1].