Active Surveillance of Multifocal Ground-Glass Opacities: Results of a Prospective Multicenter Trial (ECTOP1021)

This study aimed to evaluate the safety of active surveillance and establish an individualized management approach for multifocal ground-glass opacities (GGOs). This prospective multicenter trial (ECTOP1021, NCT06097910) enrolled patients with ≥3 GGOs (tumor diameter ≤2 cm, consolidation-to-tumor ratio [CTR] ≤0.25). The primary endpoint was 5-year overall survival; secondary endpoints included lesion progression. The surgical curative time window was defined as tumor diameter ≤2.0 cm and CTR ≤0.25, a safe radiologic profile during which patients could achieve definite cure after resection. A total of 406 patients were recruited from five centers. The cohort consisted predominantly of females (75.6%) and never smokers (87.2%), with a median age of 53 years. In total, 1,496 lesions were under surveillance, with a median of three GGOs per patient. The median diameter of the dominant lesion was 0.8 cm. At a median follow-up of 35.4 months, the 5-year overall survival was 100%. Progression occurred in 8.1% of patients, while 1.5% developed new lesions. The median increase in tumor diameter was 0.3 cm. Eight patients underwent surgery after enrollment, all pathologic stage IA1; four had invasive adenocarcinoma and four had minimally invasive adenocarcinoma. Patients were categorized into three groups based on estimated lung function loss if complete resection, with tailored strategies accordingly. Active surveillance within the surgical curative time window appears to be safe and feasible for patients with multifocal GGOs in the short term. It offers an alternative to immediate surgery and rationalized individualized, scenario-based management strategies.