Cryoablation for T1N0M0 non-small cell lung cancer using liquid nitrogen

Objectives: To evaluate local control and complications of cryoablation for T1N0M0 non-small cell lung cancer using liquid nitrogen.

Methods: This is a retrospective observational study on 101 patients with T1N0M0 NSCLC who underwent cryoablation between 2013 and 2019. Exclusion criteria included tumors without pathological diagnosis. The study population was divided into 4 groups according to the quartile of maximum tumor diameter. The study outcomes included local control, recurrence-free survival (RFS), treatment complications, and change in pulmonary function. Median follow-up period was 35 months.

Results: Tumor diameter was divided into ≤0.9 cm (n = 21), 1.0-1.2 (n = 29), 1.3-1.7 (n = 24), and ≥1.8 (n = 27). Ten patients experienced local recurrences, which were observed none in both the groups of ≤0.9 cm and 1.0-1.2 cm (0%), one in the group of 1.3-1.7 cm (4%), and the other 9 in the group of ≥1.8 cm (33 %), indicating the local control to be better in smaller tumors (p < 0.001). The 3-year RFS was 86 % in ≤0.9 cm, 97 % in 1.0-1.2 cm, 92 % in 1.3-1.7 cm, and 53 % in≥1.8 cm, indicating the survival to be better in smaller tumors (p < 0.001). No patient had treatment-related mortality. The most frequent complication was pneumothorax, with a rate of 24 %. Forced expiratory volume in 1 s at 6 months after cryoablation was 97 ± 10 % of the pretreatment one.

Conclusion: The local control and recurrence-free survival of cryoablation for T1N0M0 NSCLC was satisfactory for tumors <1.8 cm. While main complication was pneumothorax, the decrease of pulmonary function was just 3%.