Prognostic factors in oropharyngeal cancer – analysis of 627 cases receiving definitive radiotherapy
AbstractIntroduction. The aim of this retrospective analysis was to analyze the results of conventional radical radiotherapy in the treatment of oropharyngeal cancer and to identify pre-treatment and treatment-related prognostic factors for outcome. Material and methods . The records of 627 patients with oropharyngeal cancer treated with radical radiotherapy with conventional techniques were analyzed. Results. The median age was 56 years. History of tobacco abuse was present in 80.5%. Eighty six percent had stage III or IV disease. Radical radiotherapy alone was the treatment modality for 71.2% and concomitant or neoadjuvant chemotherapy was used in 28.8%. The 3-year local control (LC), loco-regional control (LRC), disease-free survival (DFS) and overall survival (OS) was 49%, 40.6%, 38.9% and 36.1% respectively. The 3-year DFS rates were 80.3% for stage I, 65.8% for stage II, 46.1% for stage III and 25.2% for stage IV disease. Multivariate analysis was performed for prognostic factors. Prior history of tobacco abuse was an independent prognostic factor for both DFS and LRC. Karnofsky Performance Score (KPS) < 80, higher nodal stage, lower total radiotherapy dose (<66 Gy) in those receiving > 60 Gy, and overall treatment time > 50 days were other independent prognostic factors for inferior DFS and LRC. KPS < 80, higher T stage, higher nodal stage, RT dose < 66 Gy and longer overall treatment time (>50 days) were independent prognostic factors for poorer local control. Conclusions . Several patient-, disease- and treatment-related variables independently affect survival outcomes after radical radiotherapy for oropharyngeal cancer. Oropharyngeal cancers in those without a history of tobacco abuse may be biologically different and more amenable to cure with radiotherapy.