Human Papillomavirus (HPV)-Related Squamous Cell Carcinoma of the Oropharynx in African-Americans and Caucasians: A Comparative Study
RD Chernock, Q Zhang, SK El-Mofty, WL Thorstad, JS Lewis. Washington University School of Medicine, St. Louis, MO
Background: HPV-related squamous cell carcinoma (SCC) of the oropharynx is well-documented as a distinct subtype of SCC. Patients with HPV-related SCC have substantially better survival rates than those with HPV-negative tumors. Differences in the incidence of HPV-related SCC between Caucasians and African-Americans have not been well examined. The aim of this study is to explore the frequency of HPV-related SCC of the oropharynx in African-Americans and Caucasians and to evaluate patient outcome in these two groups.
Design: Cases of stage III and IV oropharyngeal SCC were identified from an IRB approved radiotherapy database from 2000 to 2007. All patients received either definitive intensity-modulated radiation therapy (IMRT) or surgery followed by postoperative IMRT. In situ hybridization (ISH) for high-risk (HR) HPV subtypes and immunohistochemistry for p16, a surrogate marker of HPV-related tumors, were performed.
Results: Of 174 patients, 148 (85%) were Caucasian and 26 (15%) were African-American. There were no differences in sex, age, adjuvant chemotherapy or length of follow-up by race. HPV –ISH and p16 positive SCCs were much more common in Caucasians (63.5% and 83.1% of tumors) than in African-Americans (11.5% and 34.6% of tumors) [p <0.0001]. Caucasians were also more likely to have received postoperative IMRT rather than definitive IMRT compared to African-Americans (p=0.0011). African-Americans also had a higher frequency of T3/T4 tumors (p=0.0322). Disease-free survival was significantly shorter for African-Americans (p=0.0254). In multivariate analysis, treatment type (p=0.0002) and HPV status (p=0.0027), but not race (p=0.9834), were significant factors contributing to disease-free survival.
Conclusions: The frequency of HPV-related SCC of the oropharynx is much higher in Caucasians than in African-Americans. African-Americans presented with higher T-stage tumors and were more likely to receive definitive IMRT. The shorter disease-free survival observed in African-Americans may be due to HPV status and factors related to choice of treatment modality.
Category: Head & Neck
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 158, Tuesday Afternoon