79. Exposure to Agent Orange is Associated with Increased Recurrence after Surgical Treatment of Stage I Non-Small Cell Lung Cancer

Objective:
Approximately 3 million Americans served in the armed forces during the Vietnam War. The Department of Veterans Affairs has demonstrated that Veterans have a higher rate of lung cancer compared to the general population, which may be related to exposures sustained during service. Agent Orange (AO), one of the tactical herbicides utilized by the armed forces as a means of destroying crops and clearing vegetation, has been linked to development of several cancers including non-small cell lung cancer (NSCLC). However, traditional risk models of lung cancer survival and recurrence often do not include such exposures. We aimed to examine the relationship between AO exposure and overall survival (OS) and disease recurrence for surgically-treated stage I NSCLC.

Methods
We performed a retrospective cohort study using a uniquely compiled dataset of US Veterans with clinical stage I NSCLC. We included adult patients who served in the Vietnam War and underwent surgical resection for pathologic stage I NSCLC between 2010-2016. Our two comparative groups included those with identified AO Exposure and those who were unexposed. We used multivariable Cox proportional hazards and Fine and Gray competing risks analyses to examine OS and disease recurrence for patients with pathologic stage I disease, respectively.

Results
A total of 3958 Vietnam veterans with pathologic stage I disease were identified (994 who had AO exposure and 2964 who were unexposed). Those who had AO exposure were more likely to be male, Caucasian, and live a further distance from their treatment facility (p<0.05). Tumor size distribution, grade, and histology were similar between cohorts. Multivariable Cox proportional hazards modeling identified similar OS between cohorts (AO exposure hazard ratio 0.97; 95% CI 0.86-1.09). Patients who had AO exposure had a 19% increased risk of disease recurrence (hazard ratio 1.19; 95% confidence interval, 1.02-1.40).

Conclusions.
Veterans with known AO exposure who undergo surgical treatment for stage I NSCLC have an almost 20% increased risk of disease recurrence compared to their non-exposed counterparts. AO exposure should be taken into consideration when determining treatment and surveillance regimens for Veteran patients.

Melanie Subramanian (1), Daniel Eaton (2), Ulysses Labilles (2), Brendan Heiden (1), Su-Hsin Chang (3), Yan Yan (3), Martin Schoen (4), Mayank Patel (2), Daniel Kreisel (1), Ruben Nava (1), Bryan Meyers (1), Benjamin Kozower (1), Varun Puri, MD, MSCI (1), (1) Division of Cardiothoracic Surgery, Washington University School of Medicine/Barnes Jewish Hospital, St. Louis, MO, (2) VA St. Louis Health Care System, St. Louis, MO, (3) Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, St. Louis, MO, (4) Division of Hematology and Medical Oncology, Department of Internal Medicine, Saint Louis University, St. Louis, MO

Lorraine Cornwell

Invited Discussant

Lorraine Cornwell is a cardiothoracic surgeon with Baylor College of Medicine in Houston. With her busy clinical practice at the Michael E. DeBakey VA Medical Center (MEDVAMC), she is an important part of the CT surgery resident training program with Baylor. The MEDVAMC Cardiothoracic Surgery team provides innovative minimally invasive CT surgical services to US military veterans.  Dr Cornwell grew up in NY, went to Duke undergraduate, and UNC Chapel Hill for medical school and general surgery residency. Her CT surgery specialty training was at NY Presbyterian Cornell and Memorial Sloan Kettering. She became an AATS member in 2017. Her practice is unique in that she performs both cardiac surgical procedures as well as general thoracic surgery in an academic setting.  In addition to coronary artery bypass grafting, valve, TAVR, and aneurysm surgery, she has a special interest in minimally invasive procedures such as MAZE ablation for atrial fibrillation, Video-Assisted Thoracoscopic (VATS) lobectomy, thymectomy, and esophageal surgery. Her research interests include optimization of clinical outcomes of cardiothoracic surgery, especially minimally invasive procedures, off-pump CABG, valve repair, VATS lobectomy, and lung cancer screening, She recently received an LPOP grant (lung precision oncology program) with the VA, to fund improvements in lung cancer screening and enrollment in lung cancer clinical trials at MEDVAMC, and is on the executive committee for the VALOR trial, an important RCT now accruing to compare surgery versus SBRT for operable early stage lung cancer.  She enjoys traveling with her husband, who is an intellectual property litigator based in Houston, and time outside with her 2 dogs.

Melanie Subramanian

Abstract Presenter

Melanie Subramanian MD, MPHS is a 4/3 integrated cardiothoracic surgery fellow at Washinton University/Barnes Jewish Hospital. She has maintained an academic interest in clinical outcomes research, with a special focust n lung cancer survivorship. 

Specialties: General Thoracic, Thoracic, Lung, Anatomy and Conditions, Lung--Cancer, Lung--Other, Treatment/Procedure/Operation/Surgery, Lung, Pulmonary Disease, Lung--Cancer, Lung--Other