Precision association of lymphatic disease spread with radiation-associated toxicity in oropharyngeal squamous carcinomas

•582 oropharyngeal cancer patients under radiation treatment were analyzed.•We aim to predict post-treatment aspiration or gastronomy tube dependence.•Tumor spread patterns to head and neck lymph nodes were identified.•Patients were clustered based on their unique lymph node spread patterns.•Patient clustered were significantly correlated with dysphagia 6 months post treatment.•Lymph node spread patterns are an effective prognostic indicator of late toxicity. To determine whether patient similarity in terms of head and neck cancer spread through lymph nodes correlates significantly with radiation-associated toxicity. 582 head and neck cancer patients received radiotherapy for oropharyngeal cancer (OPC) and had non-metastatic affected lymph nodes in the head and neck. Affected lymph nodes were segmented from pretreatment contrast-enhanced tomography scans and categorized according to consensus guidelines. Similar patients were clustered into 4 groups according to a graph-based representation of disease spread through affected lymph nodes. Correlation between dysphagia-associated symptoms and patient groups was calculated. Out of 582 patients, 26% (152) experienced toxicity during a follow up evaluation 6 months after completion of radiotherapy treatment. Patient groups identified by our approach were significantly correlated with dysphagia, feeding tube, and aspiration toxicity (p