Key predictors of prolonged overall treatment time in head and neck cancer radiotherapy

Abstract Introduction: Prolonged overall treatment time (OTT) in radiotherapy (RT) for head and neck cancer (HNC), particularly beyond 49 days, has been linked to poorer tumour control and survival, primarily due to accelerated tumour repopulation. Identifying modifiable factors contributing to treatment delays may help improve outcomes. This study aimed to evaluate the association between pre-treatment clinical, nutritional and inflammatory factors and prolonged OTT. Methods: We retrospectively analysed patients with non-metastatic HNC treated with definitive or postoperative RT (with or without chemotherapy) between 2020 and 2022. Pre-treatment factors included Eastern Cooperative Oncology Group (ECOG) performance status, tumour stage, treatment modality, body mass index (BMI), weight loss, sarcopenia (via C3 computed tomography imaging), neutrophil-to-lymphocyte ratio (NLR) and absolute lymphocyte count. Logistic regression was used to identify predictors of prolonged OTT (> 49 days). Results: Among 465 patients, 287 (61·7%) experienced prolonged OTT. Multivariable analysis identified ECOG status (OR 1·42, p = 0·004), significant weight loss > 5% (OR 1·26, p = 0·036), concurrent chemotherapy (OR 1·96, p = 0·005), NLR (OR 1·03, p = 0·041) and sarcopenia (OR 1·18, p = 0·042) as independent predictors. Patient-related delays accounted for 53·3% of OTT prolongation, while public holidays contributed to 42·5%. Conclusions: Several modifiable pre-treatment factors—including poor performance status, pre-treatment weight loss, sarcopenia and systemic inflammation—were independently associated with OTT prolongation. These findings provide evidence to support early, patient-tailored interventions such as prehabilitation and intensive nutritional counselling before and during RT. In addition, system-level strategies, including staffing adjustments and compensatory scheduling during public holidays, may further reduce avoidable treatment delays and enhance care delivery.