Treatment timelines, care delivery gaps, and their impact on outcomes in postoperative radiotherapy for head and neck cancer.

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Background: Delays in treatment have been associated with inferior outcomes in head and neck squamous cell carcinoma (HNSCC). The study aimed to evaluate the impact of treatment timelines on clinical outcomes in patients with HNSCC receiving post-operative radiotherapy (PORT) and to identify patient-related, treatment-related and system-level contributors to treatment delay. Methods: This retrospective study included consecutive patients with HNSCC who completed PORT at our centre from 2021 to 2024. Electronic medical records were reviewed to collect clinical data, treatment timelines, outcomes, and reasons for treatment delays. Survival outcomes were estimated using the Kaplan–Meier method, and multivariable Cox proportional hazards regression was performed to evaluate factors associated with disease-free survival. Results: 1287 patients were eligible for the analysis, with the majority being diagnosed with oral cavity cancer (92.4%). The median interval from surgery to initiation of PORT was 44 days [Interquartile range (IQR), 38-52], with 43% of patients starting PORT within 42 days. The treatment package time (defined as time from surgery to completion of PORT) was <100 days in 1087 (84.5%) patients, with a median time of 87 days (IQR 77-96). At a median follow-up of 20 months, the 2-year locoregional control and disease-free survival (DFS) were 80% and 69%, respectively. On multivariable analysis, T4 disease HR 1.04, 95% CI 1.00–1.07; p = 0.036), N2-3 disease (HR 2.11, 95% CI 1.71–2.61; p < 0.001), and TPT≥ 100 days HR 1.42, 95% CI 1.09–1.84; p = 0.009) were independently associated with worse DFS. Prolonged TPT was predominantly attributable to modifiable factors, including wound-related complications (33.5%), socioeconomic barriers (31.5%), machine-related delays (19%), and delayed referral, especially among patients operated outside the institute (15.5%). Among patients with socioeconomic-related delays, financial constraints, travel distance, and accommodation challenges were the most common contributors. Conclusions: Prolonged treatment package time was independently associated with inferior DFS and was largely attributable to modifiable care delivery barriers such as wound-related complications, socioeconomic barriers, logistical limitations and referral delays. These findings highlight that improving care coordination, strengthening patient support systems, and streamlining referral processes may help reduce delays and improve clinical outcomes.