259 - Baseline Urinary Symptom Burden and DIL/CTV Ratio in Relation to GU Toxicity After Single-Dose Prostate Radiotherapy with Simultaneous Integrated Dominant Intraprostatic Lesion Boost
Presenter(s)
J. W. Johnson1, J. M. Napolitano2, A. C. Snavely3, C. H. Tegeler4, C. L. Nightingale5, H. D. Pacholke2,6, C. M. Furdui7, D. R. Soto-Pantoja8, T. C. Register9, K. E. Weaver5, G. J. Lesser10, and R. T. Hughes2; 1Wake Forest University School of Medicine, Winston-Salem, NC, 2Department of Radiation Oncology, Wake Forest University School of Medicine, Winston Salem, NC, 3Department of Biostatistics and Data Science, Wake Forest University School of Medicine, Winston Salem, NC, 4Department of Neurology, Wake Forest University School of Medicine, Winston Salem, NC, 5Department of Social Sciences and Health Policy, Wake Forest University School of Medicine, Winston Salem, NC, 6Atrium Health Wake Forest Baptist Hayworth Cancer Center, High Point, NC, 7Department of Internal Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston Salem, NC, 8Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, 9Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston Salem, NC, 10Department of Internal Medicine, Section of Hematology and Oncology, Wake Forest University School of Medicine, Winston Salem, NC
Purpose/Objective(s): Radiotherapy (RT) for head and neck cancer (HNC) is associated with increased risk of accelerated atherosclerosis. Previous studies utilized coronary artery calcium scores to assess the risk of a cardiovascular event, with the noninvasive tool being incorporated into global guidelines. Other studies applied the calculation to the carotid arteries yielding a carotid artery calcium score (CACS). To inform future prospective studies of a screening program, we assessed CACS in a prospective study of HNC survivors previously treated with RT.
Materials/Methods: In this prospective multi-site pilot study, patients who completed RT for HNC at least 2 years prior with no evidence of disease were enrolled. Exclusion criteria were: history of CAS, stroke, transient ischemic attack, carotid endarterectomy/stent, recurrent HNC, re-irradiation, or ECOG 2+. The DICOM RT planning and treatment data were used to calculate the CACS. The volume of interest was obtained by isolating the voxel data of both internal carotid arteries previously contoured by a board-certified radiation oncologist. Voxels with a Hounsfield Unit (HU) value =130 were identified and the HU values of those voxels were summed, multiplied by the voxel size, and divided by the HU threshold value. The average CACS of patients with plaque were compared to those without, using the Wilcoxon rank-sum test. Additionally, previously collected intima-media thickness (IMT) of the internal carotid (IC), carotid bifurcation (CB), and common carotid (CC) were compared to the CACS for each patient using Spearman’s Rank Correlation. This analysis was done for both the ipsilateral (ipsi) and contralateral (contra) sides.
Results: Sixty patients were enrolled with forty-one patients having the necessary data. Among the included patients, mean age was 64 and the most common primary site was oropharynx (64%). Previously collected ultrasound data showed eight patients (19.5%) had plaque buildup in the carotid arteries =2mm. Average CACS for the overall cohort was 130.9 (IQR 75.4-239.2), with average CACS in those with plaque was 206.0 (IQR 114.6-263.6), and average CACS in those without plaque was 130.0 (IQR 69.0-239.2). A statistically significant difference was noted between the average CACS of those with and without plaque (p<0.001). The Spearman’s rank correlation coefficient for the ipsi IC was 0.08 (p=0.61), contra IC was 0.29 (p=0.08), ipsi CB was 0.12 (p=0.44), and contra CB was 0.09 (p=0.58). A significant correlation was noted for the ipsi CC which was 0.39 (p=0.01) and contra CC which was 0.34 (0.03).
Conclusion: In this prospective study of CACS in HNC survivors, we observed that elevated CACS accurately represented patients with carotid plaque buildup. We also observed that CACS had a positive correlation with CC IMT. These findings indicate that CACS, which is calculated from CT data readily available prior to treatment, could be utilized as a baseline risk assessment to aid in surveillance decision making. (NCT05490875; WFBCCC 98322)