The long-term outcomes of follow-up care for ground-glass opacity (GGO) lesions need to be clarified.
Between 2000 and 2005, a total of 226 patients with pure or mixed GGO lesions ≤ 3 cm in size were registered. The CT findings and changes in the findings during the follow-up period and the outcomes of the 226 patients were subsequently reviewed.
Overall, 124 patients underwent resections, 57 did not receive follow-up examinations after 68 months because of stable disease or disease reduction, and 45 are continuing to receive follow-up examinations. Thirty-nine patients exhibited tumor growth during the follow-up period. Among the patients with a ratio of the diameter of consolidation relative to the tumor diameter (CTR) > 0, all cases with tumor growth were identified within 3 years; meanwhile, > 3 years were required to identify tumor growth in 16% of the patients with a CTR of 0. Aggressive cancer occurred in 4% of patients with a CTR of 0 and in 70% of patients with a CTR > 25%. Aggressive cancer was observed in 46% of the patients whose CTR increased during the follow-up period and in 8% of the patients whose tumors increased in size.
A higher CTR and an increase in CTR during follow-up were associated with invasive cancer. A follow-up period of 3 years is considered to be adequate for judging tumor growth in patients with a CTR > 0, whereas a longer follow-up period might be needed for patients with a CTR of 0.