Integration of radiobiological modeling with clinical outcomes for optimizing carotid-sparing treatment planning in head and neck cancers
Mohsin R. Khan, Malik Tariq Rasool, Malik Mohib-ul HaqABSTRACT
Background:
Radiotherapy (RT) for head and neck squamous cell carcinoma (HNSCC) can deliver significant incidental doses to the carotid arteries, increasing the risk of late vascular events. Carotid-sparing intensity-modulated radiotherapy (IMRT) with radiobiological modelling may reduce these risks without compromising tumour control.
Objective:
To assess the predictive accuracy of normal tissue complication probability (NTCP) modelling for carotid stenosis and its association with tumour control, vascular events, and quality of life in HNSCC patients treated with carotid-sparing IMRT.
Methods:
In this prospective observational study, 120 patients with HNSCC underwent carotid-sparing IMRT. Dose–volume histograms were used to calculate NTCP for carotid stenosis using the Lyman–Kutcher–Burman model, and tumour control probability (TCP) from target coverage. Patients were followed for ≥5 years with Doppler ultrasonography, MRI angiography when indicated, neurocognitive testing, and EORTC QLQ-H and N35 questionnaires. The primary endpoint was correlation between NTCP and ≥50% radiographically confirmed carotid stenosis. Kaplan–Meier, Cox regression, and ROC analyses were performed.
Results:
At 5 years, high NTCP (>8%) was associated with reduced stenosis-free survival compared to low NTCP (≤5%) (HR = 5.62; 95% CI: 2.1–14.8;
Conclusion:
NTCP modelling reliably predicts late carotid stenosis and vascular outcomes in HNSCC patients receiving IMRT and supports patient-specific carotid-sparing strategies.