Outcomes of early-stage oropharyngeal squamous cell carcinoma patients treated with radical radiation - a single institution experience.

Purpose: Treatment options for early-stage oropharyngeal squamous cell carcinomas (OPSCC) (Stages I and II) include definitive radiation or surgery. This retrospective study aims to evaluate the outcomes of early-stage (Stages I and II) OPSCC treated with radical radiation.

Materials and methods: The data of patients with early-stage OPSCC (T1/T2N0) treated with definitive radiation at the Regional Cancer Center, Trivandrum, Kerala, India, from 1st January 2015 to 31st December 2020 were retrieved from medical records. A structured proforma was used to gather clinical and therapeutic details of the patients. The primary objective was to assess loco-regional control and patterns of relapse. Secondary objectives were to assess overall survival (OS), disease-free survival (DFS) and prognostic factors affecting the treatment outcomes. DFS and OS were generated using Kaplan-Meier Curves. The prognostic factors affecting the outcomes were analysed using the Cox-proportional hazards regression model.

Results: One hundred and twelve patients with early-stage oropharyngeal cancers who received definitive radiation were included in the study. The majority (91.97%) were males and 90% (101) of the patients had tobacco and alcohol-related habits. Twenty-six (23.3%) among the 112 patients had stage I disease and 86 (76.7%) had stage II disease. The median age group of the study population was 62 years. The most commonly affected primary site was the tonsil (N = 38, 33.9%), followed by the soft palate (N = 34, 30.3%) and followed by the base of the tongue (N = 23, 20.5%). The majority of the patients (80.4% (N = 90)) received a radiotherapy (RT) dose of 60 Gy in 26 fractions at 2.3 Gy per fraction over 5.5 weeks. One hundred nine (97.3%) patients attained remission at 12 weeks following radiation. Three patients had residual disease and none of them underwent salvage surgery. Twenty-one percent (N = 24) of patients had relapsed and the median time to relapse was 20 months. Among the relapses, 7 (29%) underwent salvage surgery and others were given palliative treatment. The most frequent site of relapse was the primary site followed by regional nodes. At a median follow-up of 63 months, the 4-year DFS was 67.9% and OS was 75%. Stage-wise 4-year DFS and OS for stages 1 and II were 68.1% and 64.1%, 78.9% and 73.8%, respectively. The locoregional relapse-free survival at 4 years was 75.2%. Five patients developed a second malignancy and the lung was the most common site. In univariate analysis, age was the only significant prognostic factor that affected the treatment outcomes.

Conclusion: The survival outcomes of the patients treated with definitive RT are comparable with the published literature. However, the salvage rates were very poor.