Intensity-Modulated Radiotherapy Outcomes for Oropharyngeal Squamous Cell Carcinoma Patients Stratified by p16 Status

Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA.
Cancer (Impact Factor: 4.9). 06/2010; 116(11):2645-54. DOI: 10.1002/cncr.25040
Source: PubMed

ABSTRACT Patients with oropharyngeal squamous cell carcinoma (OPSCC) treated with intensity-modulated radiotherapy (IMRT) were stratified by p16 status, neck dissection, and chemotherapy to correlate these factors with outcomes.
A total of 112 patients with OPSCC treated with IMRT from 2002 to 2008 were retrospectively analyzed. All patients received RT to 66-70 Gray. Forty-five of the tumors were p16 positive (p16+), 27 were p16 negative (p16-), and 41 had unknown p16 status. Sixty-two patients had postradiation neck dissections. Nine patients with p16- tumors and 28 patients with p16+ tumors received chemotherapy. The distribution of T, N, and stage grouping among the p16+ and p16- patients was not significantly different, and 87.5% patients had stage III/IV disease.
The median follow-up was 26.3 months. For patients with p16+ tumors, p16- tumors, and the overall cohort, the actuarial 3-year locoregional progression-free survival rate was 97.8%,73.5%, and 90.5% respectively (P = .006) and the disease-free survival rate was 88.2%, 61.4%, and 81.7%, respectively (P = .004). Patients with p16+ tumors had an 89.5% and 87.5% pathologic complete response (CR) on neck dissection with and without chemotherapy, respectively. In contrast, patients with p16- tumors had a 66.7% and 25.0% pathologic CR on neck dissection with and without chemotherapy, respectively.
In this series, p16 status was found to be a significant predictive biomarker and patients with p16+ tumors had much better outcomes than patients with p16- tumors. Further investigation is warranted to determine whether less intense therapy is appropriate for selected patients with p16+ OPSCC, whereas more aggressive strategies are needed to improve outcomes in patients with p16- disease.

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    ABSTRACT: Background: Human papillomavirus positive (HPV+) oropharyngeal squamous cell carcinoma (OSCC) is emerging as a different subtype of head and neck cancer. The authors conducted a systematic review and meta-analysis to examine the predictive role of HPV in OSCC patients treated with radiotherapy-based modality therapy. Methods: The authors performed a PubMed search to identify published trials that evaluated the outcome of HPV+ OSCC treated with radiotherapy. Hazard ratios (HRs) were extracted and pooled by using random or fixed effects models. The primary endpoints were overall, disease-specific and disease-free survival (OS, DSS and DFS). Results: Thirty trials were available for HPV analysis. HPV+ status is associated with better OS (HR = 0.33; p < 0.00001), DSS (HR = 0.24; p < 0.00001) and DFS (HR = 0.31; p < 0.00001). Conclusions: HPV+ OSCC has a better survival compared to HPV-negative disease when treated with radiotherapy-based modality therapy. Head Neck, 2013.
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