Multicenter retrospective cohort study of PET/CT-guided management of immune checkpoint blockade in long-term responders with metastatic lung cancer

The optimal duration of immune checkpoint blockade (ICB) in lung cancer is not clear. Strategies to determine the optimal duration of ICB are urgently needed. A retrospective cohort study at 21 centers in Germany included 455 patients with metastatic lung cancer who had ≥ 2 years of disease control on first-line ICB-based therapy. Patients were grouped in to PET/CT-guided discontinuation (cohort A, n=126) or continued ICB without PET/CT (cohort B; n=329). At a median duration of follow-up of 55 months, cohort A showed significantly longer overall survival (median not reached versus 82 months; HR 0.35; p=0.002) despite substantially shorter treatment duration (27 versus 45 months; p<0.001). Discontinuation was either PET-driven (A) or resulted from immune-related toxicity, progression, of patient’s choice (B). Systematic re-biopsies in cohort A revealed a high incidence of second primary lung cancer. All progression events were managed exclusively with local (ablative) treatments in 53% (A) versus 17% (B). The authors conclude that a structured discontinuation strategy appears to provide a safe approach for long-term ICB responders.