Abstract 16436: The Relationship Between Radiation Dose Volume and Adverse Cardiovascular Events in Cancer Survivors Who Received Thoracic Radiation
Objective: The purpose of this retrospective case-controlled study was to examine the contribution of radiation therapy (RT) dose distribution on the development of significant CVD events in cancer patients within the previous 5 years.
Methods: Patients receiving initial cancer and subsequent medical care at a large Southeastern medical center were culled from medical records and databases for a sample of 28 with and 28 without secondary CVD development. All demographic and clinical variables including CVD risk and outcome data were gleaned through medical record and billing review. The risk due to RT was isolated from known CVD risk factors present at the initiation of cancer treatment. Secondly, a novel means of applying dose volume histograms (DVHs) to summarize the radiation dose delivered to the heart and each of the three main coronary arteries was calculated by a medical physicist and radiation oncologist. Analysis used paired t-tests and Logistic Regression Modeling.
Results: Case to control matching was made based upon age at cancer diagnosis [cases 62.29 +/- 8.9; controls: 61.93 +/- 9.0; (p=.571)]; gender; and cancer type. There were no significant differences between the RT dose statistics or delivery between pairs. A significant difference was observed with more cases having multiple risk factors at the time of cancer diagnosis: Cases had significantly higher BMIs (p=.009), systolic blood pressure (p=.028), glucose levels (p=.022), and calculated Framingham risk (w/BMI), (p=.001). More cases than controls were observed to have a history of CVD (McNemar’s p=.022), and diabetes (McNemar’s p=.003). No significant differences between cases and controls was observed for: ethnicity; marital status; comorbidities; smoking history; hyperlipidemia; alcohol abuse; chemotherapy type; nor use of hormone therapy.
Conclusion: The cases all had significantly greater typical CVD risk factors upon cancer diagnoses and did not receive any greater or differing amounts of thoracic radiation. A logistic regression model revealed subjects with high systolic BP, CVD history and diabetes had much higher odds of being a CVD case. After accounting for these variables, no other radiation parameters (dose, DVH, nor shape) entered the model.
Author Disclosures: C.M. Reilly: None. M. Higgins: None. E. Schreibmann: None. N. Esiashvili: None.
- © 2015 by American Heart Association, Inc.