Clinical Analysis of Pulmonary Nontuberculous Mycobacterial Infection in Patients With Pre‐Existing Stage <scp>II</scp>–<scp>IV</scp> Lung Cancer

Immune checkpoint inhibitors (ICIs) targeting programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have improved cancer outcomes but can induce immune-related adverse events, including mycobacterial infections. This study retrospectively analysed pulmonary nontuberculous mycobacteria (NTM) infection in 91 patients with pre-existing stage II-IV lung cancer at Shanghai Pulmonary Hospital between June 2015 and June 2024. Among these patients, 78.0% [71/91] were male, and 16.5% [15/91] were receiving ICIs monotherapy at the time of initial pulmonary NTM infection diagnosis (ICIs group). Compared with the non-ICIs group, ICIs-treated patients developed pulmonary NTM infection earlier (median time: 12 months [IQR, 6-18] vs. 21.5 months [IQR, 13-30]; p = 0.004), and had a higher proportion of rapid-growing NTM isolates (73.3% [11/15] vs. 30.3% [23/76]; p = 0.003), predominantly Mycobacterium abscessus complex (40.0% [6/15]). In contrast, Mycobacterium avium complex was the predominant NTM species in the non-ICIs group (71.1% [54/76]). During 12 months of anti-NTM therapy, the ICIs group showed a lower cumulative sputum culture conversion rate (36.4% [4/11] vs. 59.6% [31/52]; p = 0.19) and a longer median time to initial sputum culture conversion (12 months vs. 6 months; p = 0.13), though these differences were not statistically significant. The most commonly administered ICIs drugs were tislelizumab (40.0% [6/15]) and sintilimab (26.7% [4/15]). These findings suggest that ICIs may be associated with earlier development of pulmonary NTM infection in lung cancer patients. Future prospective studies with larger sample sizes are needed to validate this conclusion.