Effect of Heavy Smoking History on HPV-Positive Tumors and Racial Disparities Among African American Patients With Tonsillar Cancer

Abstract

To evaluate the outcomes of patients with tonsillar cancer treated at our institution between 2006 and 2015 and to identify differences among races with regards to overall survival (OS) and disease free survival (DFS) at 3 years. We retrospectively reviewed 84 patients with squamous cell carcinoma of the tonsil. 66/84 patients had stage III/IV disease (AJCC 7th edition staging). 58/84 patients had their HPV status evaluated (29 HPV-positive and 29 HPV-negative). There were 50 white patients, 33 African-American (AA) patients, and 1 Native American patient. The majority of patients were treated with concurrent chemoradiotherapy consisting of weekly Cisplatin or weekly Cetuximab for 7 weeks. Radiation therapy was given using Intensity Modulated Radiation Therapy to 70 Gy at 2 Gy per fraction over 7 weeks. Median follow-up time was 3 years (1.5-10 years). We evaluated the outcomes at 3 years including OS and DFS. Rates were estimated by Kaplan-Meier method and comparisons between groups were evaluated using Fisher's exact test and Pearson Chi Square test for categorical variables. OS for the entire group was 64% at 3 years with a DFS rate of 76%. OS for AA patients was 49% vs. 75% for white patients (p=.0001). DFS for AA patients was 51% vs 93% in white patients (p=.0001). AA patients classified as intermediate and high risk based on RTOG recursive-partitioning analysis accounting for smoking history and HPV status had worse OS and DFS compared to intermediate/high risk white patients, 44% vs 68% (p=.047) and 36% vs 94% (p=.002), respectively. Among patients with stage III/IV disease, AA patients had worse OS and DFS as compared to white patients, 41% vs 75% (p=.002), and 42% vs 91% (p=.0001), respectively. AA patients with N2/N3 disease had worse OS and DFS than white patients with N2/N3 disease, 44% vs 78% (p=.007) and 43% vs 93% (p=.001). Among patients with heavy smoking history (≥10 pack years), AA patients had worse OS and DFS than white patients, 42% vs 69% (p=.012), 37% vs 97% (p=.0001), respectively. AA patients with HPV-positive tumors had worse DFS than white patients with HPV-positive tumors, 50% vs 90% (p=.046). Significant differences in OS and DFS in patients with tonsillar cancer were identified based on race. AA patients presented with more advanced T and N staged disease. In all patients with advanced disease, AA patients had a worse OS and DMFS. AA patients with HPV-positive tumors and heavy smoking history also had worse outcomes than corresponding white patients with HPV-positive tumors. We conclude that AA patients appear to have a more aggressive behaving disease when controlling for other factors as compared to white patients. The interplay of HPV status and race among intermediate risk patients should be subject for additional investigation as our study demonstrates that AA patients classified as intermediate risk may have outcomes more similar to high risk patients and thus race may be an important part of future staging systems.