The value of tumor diameter in predicting prognosis of oropharynx cancer treated with chemoradiation

SummaryObjectivesThe tumor node metastasis (TNM) system is the most widely used staging system for cancers of the oropharynx, yet is known to omit key prognostic indicators. Tumor volume has been shown in other head and neck sites to add predictive power but is not as useful in the oropharynx. This study investigates the value of other methods in quantifying tumor burden.MethodsTreatment plans of oropharyngeal cancer patients treated non-operatively were retrospectively reviewed. Potential prognostic factors including TNM, demographics, smoking history, and various tumor dimensions were analyzed.ResultsRecords identified 93 patients treated with definitive concurrent chemoradiation who had at least one year of follow-up and a clear GTV contour on the original treatment plan. On univariate analysis, tumor diameter and tumor volume showed a significant relationship to overall and disease-free survival. Tumor stage, age and smoking history showed significance in regard to overall survival. On multivariate analysis tumor diameter showed independent significance but not TNM or tumor volume.ConclusionOur method of measuring tumor diameter has independent prognostic significance in the oropharynx where GTV has shown questionable value.