Longitudinal Changes in the Carotid Arteries of Head and Neck Cancer Patients Following Radiation Therapy: Results from a Prospective Serial Imaging Biomarker Characterization Study.

Introduction: We prospectively evaluated morphologic and functional changes in the carotid arteries of patients treated with unilateral neck radiation therapy (RT) for head and neck cancer.

Methods: Bilateral carotid artery duplex studies were performed at 0, 3, 6, 12, 18 months and 2, 3, 4, and 5 years following RT. Intima media thickness (IMT); global and regional circumferential, as well as radial strain, arterial elasticity, stiffness, and distensibility were calculated.

Results: Thirty-eight patients were included. A significant difference in the IMT from baseline between irradiated and unirradiated carotid arteries was detected at 18 months (median, 0.073mm vs -0.003mm; =0.014), which increased at 3 and 4 years (0.128mm vs 0.013mm, =0.016, and 0.177mm vs 0.023mm, =0.0002, respectively). A > 0.073mm increase at 18 months was significantly more common in patients who received concurrent chemotherapy (67% vs 25%; =0.03). A significant transient change was noted in global circumferential strain between the irradiated and unirradiated arteries at 6 months (median difference, -0.89, =0.023), which did not persist. No significant differences were detected in the other measures of elasticity, stiffness, and distensibility.

Conclusions: Functional and morphologic changes of the carotid arteries detected by carotid ultrasound, such as changes in global circumferential strain at 6 months and carotid IMT at 18 months, may be useful for the early detection of radiation-induced carotid artery injury, can guide future research aiming to mitigate carotid artery stenosis, and should be considered for clinical surveillance survivorship recommendations after head and neck RT.