Persistent pulmonary subsolid nodules with solid portions of 5 mm or smaller: Their natural course and predictors of interval growth

To investigate the natural course of persistent pulmonary subsolid nodules (SSNs) with solid portions a parts per thousand currency sign5 mm and the clinico-radiological features that influence interval growth over follow-ups. From 2005 to 2013, the natural courses of 213 persistent SSNs in 213 patients were evaluated. To identify significant predictors of interval growth, Kaplan-Meier analysis and Cox proportional hazard regression analysis were performed. Among the 213 nodules, 136 were pure ground-glass nodules (GGNs; growth, 18; stable, 118) and 77 were part-solid GGNs with solid portions a parts per thousand currency sign5 mm (growth, 24; stable, 53). For all SSNs, lung cancer history (p = 0.001), part-solid GGNs (p < 0.001), and nodule diameter (p < 0.001) were significant predictors for interval growth. On subgroup analysis, nodule diameter was an independent predictor for the interval growth of both pure GGNs (p < 0.001), and part-solid GGNs (p = 0.037). For part-solid GGNs, lung cancer history (p = 0.002) was another significant predictor of the interval growth. Interval growth of pure GGNs a parts per thousand yen10 mm and part-solid GGNs a parts per thousand yen8 mm were significantly more frequent than in pure GGNs < 10 mm (p < 0.001) and part-solid GGNs < 8 mm (p = 0.003), respectively. The natural course of SSNs with solid portions a parts per thousand currency sign5 mm differed significantly according to their nodule type and nodule diameters, with which their management can be subdivided. aEuro cent Pure GGNs a parts per thousand yen10 mm have significantly more frequent interval growth than those < 10 mm. aEuro cent Part-solid GGNs a parts per thousand yen8 mm have significantly more frequent interval growth than those < 8 mm. aEuro cent Management of SSNs with solid portions a parts per thousand currency sign5 mm can be subdivided by diameter.