Clinical characteristics and prognostic analysis of patients with connective tissue disease complicated by non-small cell lung cancer.

AIMS: To summarize the clinical features, treatment patterns and survival outcomes of patients with non-small cell lung cancer (NSCLC) combined with connective tissue disease (CTD), and to determine whether CTD independently influences prognosis and treatment-related toxicity in this special patient population.

METHODS

In this retrospective study, we enrolled 200 consecutive patients with pathologically confirmed NSCLC. Among them, 95 patients met the diagnostic criteria for CTD were set as the CTD group, and the remaining 105 patients with simple NSCLC as the control group. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), baseline tumor characteristics, metastatic patterns, first-line treatment patterns and delivery, and treatment-related adverse events (AEs). We adopted Kaplan-Meier method for survival analysis and Cox proportional hazards regression model for prognostic analysis. Prespecified subgroup analyses were performed to evaluate the prognostic effect of CTD and identify independent survival predictors.

RESULTS

The CTD group presented more severe intrathoracic tumor dissemination, including higher incidence of bilateral pulmonary lesions (P = 0.042) and pleural effusion (P = 0.011). Compared with controls, the CTD group were less likely to receive platinum-based doublet chemotherapy (P = 0.035), cisplatin-based chemotherapy (P = 0.017), immune checkpoint inhibitor (ICI)-containing therapy (P = 0.009) and thoracic radiotherapy (P = 0.029). Meanwhile, the CTD group had higher risks of chemotherapy dose reduction (P = 0.011), treatment delay longer than 7 days (P = 0.015) and early treatment discontinuation (P = 0.002). In survival outcomes, the median PFS was 5.4 vs 7.8 months (HR, 1.58; 95% CI, 1.17-2.13; P = 0.003), and the median OS was 9.7 vs 14.6 months (HR, 1.76; 95% CI, 1.29-2.40; P<0.001). The incidence of grade 3-4 treatment-related AEs was significantly higher in the CTD group (P = 0.010). Multivariate regression analysis confirmed that CTD was an independent adverse prognostic factor for poor OS (HR, 1.41; 95% CI, 1.01-1.97; P = 0.044).

CONCLUSION

For patients diagnosed with NSCLC, comorbid CTD is correlated with aggravated intrathoracic tumor dissemination, reduced treatment intensity and treatment tolerance, increased severe toxicity, and dismal long-term survival.