Wesley Russell, Presenter: Nothing to Disclose

Wade L. Thorstad MD, Abstract Co-Author: Nothing to Disclose

Bruce H. Haughey MD, MS, Abstract Co-Author: Nothing to Disclose

Joseph O. Deasy PhD, Abstract Co-Author: Nothing to Disclose

Issam El Naqa PhD, Abstract Co-Author: Nothing to Disclose

To determine the impact of tumor volume on locoregional recurrence (LR) and overall survival (OS) in patients receiving definitive and post-op IMRT for oropharyngeal cancer.

Subjects included 82 patients with squamous cell carcinoma of the oropharynx treated with IMRT (39 post-op and 43 definitive) between 1998 and 2005 with available volumetric imaging. Mean age at diagnosis was 57; 91% were male; 9% were female; 59% received chemotherapy; median gross volume of the tumor (GTV-T), lymph node (GTV-N), and tumor + node (GTV-TOT) was 13.5 ml, 17, and 33, respectively. Of the tumor volumes, only GTV-T was significantly different between post-op and definitive patients (p=0.03). The median GTV-T was 10 ml in post-op patients and 17 ml in definitive patients. Univariate and multivariate analyses were used to identify prognostic factors for LR and OS. Prognostic factors included age, sex, treatment objective, grade, site group, stage group, T-stage, N-stage, chemotherapy, CTV1 dose, fraction size, GTV-T, GTV-N, and GTV-TOT. For post-op IMRT patients, the tumor volume was measured using preoperative CT, MRI, and/or PET/CT scans.

The median follow-up time for living patients was 32.2 months. Significant factors (at p 57.5. For OS in all patients, GTV-TOT with optimal cutoff of 40 ml was most significant (p=0.0003), with 5-year overall survival of 55% for GTV-TOT 40 ml.

Based on our results, total tumor volume (GTV-T plus GTV-N) seems to have both statistical and clinical prognostic values for LR and OS in patients receiving definitive IMRT for squamous cell carcinoma of the oropharynx. Surgery appears to greatly reduce the impact of tumor volume on LR and OS.

Russell, W, Thorstad, W, Haughey, B, Deasy, J, El Naqa, I, Impact of Tumor Volume in Definitive and Postoperative Oropharyngeal Cancer Treated with IMRT.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/7000173.html