Background: Locally advanced head and neck squamous cell carcinoma (LA-HNSCC) continues to have suboptimal outcomes, with locoregional and distant failures remaining a significant cause of morbidity and mortality despite advances in radiotherapy techniques. This study evaluated failure patterns and survival outcomes following definitive intensity-modulated radiotherapy (IMRT) in LA-HNSCC.
Materials and methods: An ambispective analysis was conducted on LA-HNSCC patients who received definitive IMRT with weekly concurrent chemotherapy. Locoregional failures (both residual disease and new loco-regional recurrences) as well as distant metastases were identified. Patterns of failure were categorised as local, regional or distant. Kaplan-Meier method was used to assess survival outcomes and univariate and multivariate Cox regression models were utilised to identify factors associated with failures and survival.
Results: A total of 332 patients were analysed, with a median age of 58 years; 94% had stage III–IVB disease and 83.1% received concurrent chemotherapy. At a median follow-up of 10 months, failure was observed in 44.9% of patients. Local control rates at 3, 6, 12 and 24 months were 97.9%, 81.6%, 69.9% and 52.5%, respectively. Local failure was the most common failure pattern (33.4%), followed by regional (15.6%) and distant failure (9.3%). Primary tumour volume greater than 30 cc and an oral cavity primary site were independent predictors of local failure. Median disease-free survival and overall survival were 8.3 and 13.8 months, respectively.
Conclusion: Despite the use of modern IMRT techniques, locoregional failure - particularly local failure - remains the predominant pattern of treatment failure in LA-HNSCC. Primary tumour volume is a critical determinant of outcome, highlighting the need for volumetric risk stratification and individualised treatment strategies to improve disease control in high-risk patients. However, the interpretation of survival outcomes should be considered in light of the wide range of follow-up duration in this cohort, which represents a limitation of the present study.
