Abstract
Objectives/Hypothesis: To evaluate the responsiveness of human papillomavirus (HPV) -positive and HPV-negative oropharyngeal cancer to intensity-modulated radiotherapy (IMRT), using axial imaging obtained daily during the course of image-guided radiotherapy (IGRT). Study Design: Observational cohort study with matched-pair analysis of patients irradiated for HPV-positive and HPV-negative oropharygeal cancer. Methods and Materials: Ten patients treated by IMRT to 70 Gy for locally advanced, HPV-positive squamous cell carcinoma of the oropharynx were matched to one HPV-negative control subject by age, gender, performance status, T-category, tumor location, and the use of concurrent chemotherapy. The gross tumor volume (GTV) was delineated on daily IGRT scans obtained via kilovoltage cone-beam computed tomography (CBCT). Mathematical modeling using fitted mixed-effects repeated measure analysis was performed to quantitatively and descriptively assess the trajectory of tumor regression. Results: Patients with HPV-positive tumors experienced a more rapid rate of tumor regression between day 1 of IMRT and the beginning of week 2 (-33% Δ GTV) compared to their counterparts with HPV-negative tumors (-10% Δ GTV), which was statistically significant (p<0.001). During this initial period, the average absolute change in GTV was -22.9 cc/week for HPV-positive tumors and -5.9 cc/week for HPV-negative tumors (p<0.001). After week 2 of IMRT, the rates of GTV regression were comparable between the two groups. Conclusions: HPV-positive oropharyngeal cancers exhibited an enhanced response to radiation, characterized by a dramatically more rapid initial regression than those with HPV-negative tumors. Implications for treatment de-intensification in the context of future clinical trials and the possible mechanisms underlying this increased radiosensitivity will be discussed. Laryngoscope, 2013
Original language | English (US) |
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Pages (from-to) | 152-157 |
Number of pages | 6 |
Journal | Laryngoscope |
Volume | 123 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2013 |
Keywords
- head and neck cancer
- Human papillomavirus
- Level of Evidence: 3B
- radiation therapy
- radiosensitivity
- squamous cell carcinoma
ASJC Scopus subject areas
- Otorhinolaryngology