PB0924 - Venous thromboembolism risk in lung cancer patients receiving first-line immune checkpoint inhibitor versus chemotherapy

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Ang Li, MD, MS

Assistant Professor
Section of Hematology-Oncology, Baylor College of Medicine
Houston, Texas, United States

Co-Author(s)

SM

Sarah May

Statistician
Baylor College of Medicine
Houston, Texas, United States
JL

Jennifer La

Principal Data Scientist
U.S. Department of Veterans Affairs
Boston, Massachusetts, United States
Kylee Martens, MD (she/her/hers)

Fellow Physician
Oregon Health & Science University
Portland, Oregon, United States
CA

Christopher Amos

Associate Director of Quantitative Science
Baylor College of Medicine
Houston, Texas, United States
CF

Christopher Flowers

Division Head ad interim, Cancer Medicine
MD Anderson Cancer Center
Houston, Texas, United States
ND

Nhan V Do

Director of the Informatics Center
Massachusetts Veterans Epidemiology Research and Information Center (MAVERIC)
Boston, Massachusetts, United States
MB

Mary T Brophy

Assistant Professor, Medicine
Boston University; VA Boston Healthcare System
Boston, Massachusetts, United States
VC

Vipul Chitalia

Associate Professor
Boston University Chobanian & Avedisian School of Medicine
Boston, Massachusetts, United States
KR

Katya Ravid

DSc, PhD, Barbara E. Corkey Professor of Medicine
Department of Medicine and Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
Boston, Massachusetts, United States
JG

J. Michael Gaziano

Adjunct Professor
Boston University Chobanian & Avedisian School of Medicine
Boston, Massachusetts, United States
NF

Nathanael Fillmore

Associate Director (Data Science)
VA Boston Healthcare System, Harvard Medical School
Boston, Massachusetts, United States

Background: It remains unclear if immune checkpoint inhibitor (ICI) therapy is associated with higher rate of venous thromboembolism (VTE) compared with cytotoxic chemotherapy (chemo) in patients with comparable cancer type, staging, comorbidities, and most importantly, line of therapy.

Aims: To determine the difference in VTE incidence in patients with advanced lung cancers initiating first-line ICI vs. chemo.

Methods: Using the national Veterans Affairs healthcare system database 2016-2021, we performed an inverse propensity score (PS)-weighted (IPW) retrospective cohort study. The PS model utilized overlap weights to balance age, sex, race, treatment year, VTE history, paralysis/immobilization, prolonged hospitalization, cancer histology, staging, time between diagnosis/treatment, and NCI comorbidity index (Figure 1). Weighted Cox regressions with robust standard error were used for analyses.

Results: Among patients with advanced lung cancers, the number of first-line ICI/chemo combination, ICI monotherapy, and chemo were 828, 428, and 4,371, respectively. Significant cross-group differences in baseline covariates were balanced after IPW (standardized difference < 0.10). Median follow-up was 9.1 months (IQR 3.7-18.3). The 6-month weighted VTE was 9.6%, 10.0%, and 9.0% for ICI/chemo, ICI, and chemo, respectively. The weighted HRs for VTE were 1.08 (0.83-1.42) for ICI/chemo vs. chemo and 1.05 (0.77-1.42) for ICI vs. chemo (Figure 2A-B). In contrast, the weighted HRs for mortality were 0.85 (0.76-0.94) and 0.78 (0.69-0.89) for the same comparisons (Figure 2C-D).

Conclusion(s): In this PS-weighted analysis in patients with advanced lung cancers, first-line ICI, with or without concurrent chemo, was associated with similarly elevated risk of VTE but reduced risk of mortality compared with chemo alone. Past studies reached inconclusive findings on the incidence of ICI-associated VTE due to the lack of a contemporary control group, mixture of first/second-line ICI, and inclusion of cancer types with inherently different VTE risks. Our findings can inform prospective studies exploring prophylaxis strategies and how treatment-specific mechanisms induce prothrombotic states.