Radiation Therapy Is Associated With an Increased Incidence of Cardiac Events in Patients with Small Cell Lung Cancer

• Type of Material: Article
• Authors: Matthew J. Ferris, Emory University; Renjian Jiang, Emory University; Madhusmita Behera, Emory University; Suresh S Ramalingam, Emory University; Walter J Curran, Emory University; Kristin Higgins, Emory University
• Language: English
• Date: 2018-10-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2018 Elsevier Inc. CC BY NC ND 4.0
• Final Published Version (URL): http://dx.doi.org/10.1016/j.ijrobp.2018.05.066
• Title of Journal or Parent Work: International Journal of Radiation Oncology - Biology - Physics
• ISSN: 0360-3016
• Volume: 102
• Issue: 2
• Start Page: 383
• End Page: 390
• Keywords: Life Sciences & Biomedicine; MEDIASTINAL IRRADIATION; DAILY THORACIC RADIOTHERAPY; Radiology, Nuclear Medicine & Medical Imaging; LONG-TERM SURVIVORS; Oncology; PHASE-3; TRIALS; EXPOSURE; PERFUSION; HEART-DISEASE; HODGKINS-DISEASE; Science & Technology; RISK
• Research Categories: Physics, Radiation; Health Sciences, Oncology

Abstract

Purpose: Cardiac radiation dose was a predictor of inferior overall survival in the Radiation Therapy Oncology Group 0617 non-small cell lung cancer trial. We examined the association between radiation therapy (RT) and cardiac events (CE) for patients with small cell lung cancer (SCLC). Methods and Materials: The US population–based Surveillance, Epidemiology, and End Results Program and Medicare claims databases were queried for rates of CE among patients with SCLC treated with chemotherapy (CTX) ± RT. Propensity score matching (PSM) and multivariate analysis were conducted. Patients were matched for actual/theoretical RT start date (to prevent immortal time bias) and then full PSM balanced clinical characteristics. Cumulative incidence function curves were generated. Results: From 2000 to 2011, 7060 patients were included: 2892 limited-stage SCLC (LS-SCLC) and 4168 extensive-stage SCLC. Grouping LS-SCLC and extensive-stage SCLC together, the incidence of CE for the CTX + RT and CTX-only groups was 44.1% versus 39% at 60 months (P =.008). After PSM (5286 patients), the incidence of CE for the CTX + RT and CTX-only groups was 43% versus 38.6% at 60 months (P =.033). Analysis of only LS-SCLC (2016 patients) demonstrated that the incidence of CE for CTX + RT versus CTX-only groups was 50.3% versus 42% at 60 months (P =.0231). Multivariate analysis again demonstrated an association between CE and RT (hazard ratio 1.20; 95% confidence interval 1.06-1.37; P =.005). After PSM (1614 patients), the incidence of CE for CTX + RT versus CTX-only groups was 51.7% versus 41.6% at 60 months (P =.0042). Conclusions: Patients with SCLC are at significant risk of developing CE posttreatment; RT is associated with an absolute increase in the rate of CE at 5 years of approximately 5% for all patients with SCLC and up to 10% for patients with LS-SCLC. Cardiac risk management and cardiac-sparing RT techniques should be further evaluated for patients with SCLC.