Patterns of failure and prognostic factors for radically treated patients of oropharyngeal cancers planned by two-dimensional radiotherapy: An audit from a regional cancer center

Objectives: To review the patterns of failure and analyze various prognostic factors influencing the outcomes of radically treated patients of oropharyngeal squamous cell cancer treated at our institute with two-dimensional planning (2D). Materials and Methods: Case records of 100 oropharyngeal squamous cell cancers, which were treated radically with radiation or concurrent chemoradiation to an equivalent dose of 66 Gy in conventional fractionation, in our department between 2011 and 2013 were retrospectively analyzed for locoregional control (LRC), progression-free survival (PFS), patterns of failure, and various prognostic factors. Results: Median age of presentation was 53 years, 95% being males. Ninety-three percent had a history of tobacco use. Base of tongue was the most common site in 63% of patients followed by tonsil in 26%. All patients were of Stage III and IV. Among these patients, 27% received concurrent chemoradiation while others received radical radiation. At a median follow-up of 28 months, 57% of the patients were disease free and the LRC was 60%. Among the recurrences, 17% had local failures while 23% had nodal failures as the first site of recurrence. There were no marginal failures. On multivariate analysis, stage of the disease was the single most important prognostic factor determining the PFS and LRC. Conclusion: Stage appears to be the most important prognostic factor affecting LRC and PFS. Absence of marginal failures in our study implies adequacy of coverage with 2D treatment planning while in-field failures mandate attempts to use increased dose, chemosensitizers or nodal dissection postradical radiation