Comparative Outcomes of Immune Checkpoint Inhibitor and Chemotherapy in Lung Cancer Patients: A Multi-Ethnic Retrospective Analysis
Authors: Tamdin Tenzin , Chiang Cho-Han , Song Junmin , Chang Yu , Chi Kuan-Yu , Peng Chun-Yu , Chang Yu-Cheng 
Published: December 2024

Background: The combination of immune checkpoint inhibitors (ICI) and chemotherapy has revolutionized the treatment landscape for lung cancer. However, both ICI and chemotherapy are well-known risk factors for thromboembolism. Additionally, racial disparities can influence adverse effects and treatment outcomes in lung cancer patients. This retrospective cohort study aimed to examine racial disparities in thromboembolic outcomes among patients with lung cancer treated with combined ICI and chemotherapy.

Methods: The retrospective cohort analysis utilized data from the TriNetX Global Collaborative Network, which includes records from 126 healthcare organizations. We included adult patients with lung cancer who were treated with ICI and chemotherapeutic agents. The index date was defined as the start date of ICI and chemotherapy. Patients with a history of venous thromboembolism, myocardial infarction, or ischemic stroke prior to the index date were excluded. Patients were stratified by race into Caucasian, African American, Asian, and Hispanic cohorts, with the Caucasian cohort serving as the control group. We compared the African American, Asian, and Hispanic cohorts to the Caucasian cohort. The cohorts were matched in a 1:1 ratio based on predetermined clinical variables such as age, sex, metastatic disease, and underlying comorbidities. The primary outcomes were arterial thromboembolic events (ATE), including myocardial infarction (MI) and ischemic stroke, and venous thromboembolic events (VTE), including pulmonary embolism (PE) and deep venous thrombosis (DVT). The secondary outcome was all-cause mortality.

Results: We identified 2,412 African Americans, 18,102 Caucasians, 1,105 Asians, and 596 Hispanics. We matched 2,384, 1,103, and 594 patients in the African American/Caucasian, Asian/Caucasian, and Hispanic/Caucasian comparison cohorts, respectively. After matching, all covariates including the basic demographics, underlying comorbidities, and metastatic disease were similar between the cohorts. In a Cox proportional hazards analysis, African Americans had a higher survival probability compared to Caucasians (hazard ratio [HR], 0.84 [95% CI: 0.76-0.93]). Similarly, both Asians (HR, 0.80 [95% CI: 0.70-0.93]) and Hispanics (HR, 0.82 [95% CI: 0.69-1.00]) had a higher survival probability compared to Caucasians. There were no significant differences in the risk of VTE (HR, 1.00 [95% CI: 0.83-1.20]), ATE (HR, 1.00 [95% CI: 0.80-1.27]), or individual components of these thrombotic events between African Americans and Caucasians. Likewise, there were no significant differences in the risk of VTE (HR, 1.08 [95% CI: 0.716-1.63]), ATE (HR, 1.2 [95% CI: 0.75-1.86]), or individual components of these thrombotic events between Hispanic and Caucasians.The risks of VTE (HR, 0.67 [95% CI 0.48-0.93]) and PE (HR, 0.61 [95% CI: 0.42-0.90]) were lower in Asians than in Caucasians. There were no differences observed in the risk of DVT (HR, 0.70 [95% CI: 0.43-1.15]) or ATE (HR, 1.30 [95% CI: 0.89-1.90]) between in Asians and Caucasians.

Conclusion: Among lung cancer patients receiving ICI and chemotherapy, the African American, Asian, and Hispanic cohorts showed decreased mortality compared to the Caucasian cohort. The Asian cohort, in particular, had a lower risk of VTE, in particular PE compared to the Caucasian cohort. There were no differences in the risks of VTE or ATE between the African American or Hispanic cohorts and the Caucasian cohort.