Risk-adjusted partial dependency plots of 1-year survival and cancer recurrence after lung resection for non–small cell lung cancer. Never-smokers are represented by blue lines; ever-smokers, by red lines. Parallel lines represent similar survival trajectories for never- and ever-smokers. Diverging or crossing lines represent differences in survival implications for never- and ever-smokers, such as for histopathological type, presence of metastatic disease, crossing lines for tumor size, vascular margin and invasion, and lymphovascular invasion. Histology: 1 = adenocarcinoma, 2 = squamous cell cancer; focality: 0 = unifocal, 1 = multifocal; laterality: 0 = right, 1 = left; location: 1 = right upper, 2 = right middle, 3 = right lower, 4 = left upper, 5 = left lower, 6 = right central, 7 = left central. A, Survival. B, Freedom from cancer recurrence. VPI, Visceral pleural invasion.