Intensity-modulated radiotherapy outcomes for oropharyngeal squamous cell carcinoma patients stratified by p16 status

✍ Scribed by Asal Shoushtari; Mathew Meeneghan; Ke Sheng; Christopher A. Moskaluk; Christopher Y. Thomas; James F. Reibel; Paul A. Levine; Mark J. Jameson; Kimberly Keene; Paul W. Read

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 217 KB
• Volume: 116
• Category: Article
• ISSN: 0008-543X
• DOI: 10.1002/cncr.25040

✦ Synopsis

Abstract

BACKGROUND:

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.

METHODS:

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.

RESULTS:

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.

CONCLUSIONS:

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. Cancer 2010. © 2010 American Cancer Society.