A 50-year-old man with a 30 pack-year smoking history presents with a 25 mm spiculated right upper lobe nodule found incidentally on CT. He has no symptoms. PET-CT shows SUV max of 6.5 in the nodule with no mediastinal or distant uptake. According to Brock University cancer prediction model, what factor most significantly increases his pre-test probability of malignancy?
- A Spiculated margins ✓
- B Upper lobe location
- C Female sex
- D Age less than 55 years
Correct answer: A. Spiculated margins
Explanation
Spiculated margins are one of the strongest independent predictors of malignancy in pulmonary nodules, increasing pre-test probability significantly. Other strong predictors include larger size, upper lobe location, and older age. Female sex actually increases risk in never-smokers. The Brock model incorporates spiculation as a high-weight variable. Spiculation suggests tumor infiltration into surrounding tissue, highly suggestive of lung cancer.
Reference: BTS Guidelines for Investigation and Management of Pulmonary Nodules, 2015 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.