Impact of Latent Tuberculosis Infection and T-SPOT.TB Dynamics Alterations on Prognosis in Advanced NSCLC Treated With ICIs--IPTW-Based Retrospective Study

Background To investigate the impact of latent tuberculosis infection (LTBI) on the prognosis of non-small cell lung cancer (NSCLC) patients treated with anti-PD-1 immunotherapy and to assess the correlation between dynamic alterations in T-SPOT.TB results and prognosis. Methods This retrospective cohort study analyzed clinical data from 127 patients with NSCLC who received anti-PD-1 therapy and underwent T-SPOT.TB testing at our institution between January 2020 and March 2024. Baseline imbalances between groups were addressed using inverse probability of treatment weighting (IPTW). Restricted cubic spline (RCS) modeling, Cox regression and other analyses were conducted both before and after IPTW. Results Among the entire cohort, 50 patients were in the LTBI group and 77 in the Normal group. No significant differences were observed in mPFS or mOS between the two groups. RCS analysis revealed a nonlinear (U-shaped) relationship between pre-TSPOT values and OS. Patients with a T-SPOT positive (but value ⩽18) exhibited longer OS compared with the other two groups (HR = 0.13, 95% CI [0.03 ~ 0.54], P = .005; after IPTW HR = 0.21, 95% CI [0.05-0.90], P = .035). Among 63 patients monitored for dynamic TSPOT changes, 35 (55.56%) remained persistently negative, 15 (23.81%) remained persistently positive, 2 (3.17%) converted from negative to positive, and 11 (17.46%) converted from positive to negative. No significant differences in ORR, PFS, or OS across these groups. Conclusions Although no statistically significant differences in treatment efficacy and prognosis were observed between the LTBI and Normal groups, this finding should not be interpreted as therapeutic equivalence, particularly given the limited sample size. Pre-treatment T-SPOT values showed a nonlinear (U-shaped) relationship with patient prognosis (OS). Lower pre-treatment T-SPOT value were associated with longer OS. The dynamic changes in T-SPOT during treatment were not significantly associated with outcomes. Four patients developed active tuberculosis during immunotherapy, with heterogeneous T-SPOT patterns, underscoring the need for TB monitoring in ICI-treated patients.