Oncology, Bismarck, ND, 2 University of Iowa Holden Comprehensive Cancer Center, Dept of Pathology, Iowa City, IA, 3 Sanford Health, Dept of Head and Neck Surgery, Sioux Falls, SD, 4 University of Iowa Hospitals & Clinics, Iowa City, IA, 5 St. Alexius CHI Medical Center, Dept of Pathology, Bismarck, ND, 6 Mid-Dakota Clinic and CHI St. Alexius Medical Center, Dept of Head and Neck Surgery, Bismarck, ND, 7 University of South Dakota Sanford School of Medicine, Sioux Falls, SD, 8 Sanford Health, Dept of Pathology, Bismarck, ND, 9 Bismarck Cancer Center, Dept of Radiation Oncology, Bismarck, ND Purpose/Objective(s): Nodal ECE is an established risk factor for HNC recurrence and mortality; however, it is unknown whether ECE impacts outcomes for HPV+ HNC. Materials/Methods: This was a retrospective multi-institutional compar- ative outcomes analysis by HPV/p16 status. Eligible patients had patho- logic confirmation of ECE for HNC involving the oropharynx (OP), oral cavity (OC), or unknown primary (UP), and underwent curative-intent therapy. Patients with metastatic disease at diagnosis, unknown HPV/p16 status, or <3 month follow-up were excluded. Results: From 2003 to 2014, 76 patients were eligible for this study. The median age at diagnosis was 60 years (range 29-82), with 46 involving the OP, 28 the OC, and 2 of UP. Forty-one patients (54%) had HPV+ tumors. All but 5 patients underwent therapeutic neck dissection, and the primary site was resected in 65 patients. For resected primary cases, 38, 23, and 4 patients underwent adjuvant chemoradiation therapy (CRT), radiation therapy (RT) alone, and no adjuvant therapy, respec- tively. For 9 patients who underwent definitive RT, 7 received concur- rent CRT. Of note, 40% of HPV+ and 35% of HPVe patients did not receive chemotherapy (PZNS). The median number of nodes excised and involved were 27 (1-92) and 2 (1-32), respectively. At a median follow-up of 26.3 months (range, 1.4-104.0; median 34.1 for survivors), 52 patients were alive (48 without recurrence, 4 with salvaged recur- rence), and 24 patients had died (21 of HNCa). Patterns of failure included local (nZ6), regional (6), locoregional + distant (6), and distant only (4). In comparing the HPV+ and HPVe groups, disease- free and overall survival was superior for the HPV+ group (P< .01; Table 1). HPV+ patients were more likely to be male (93% vs 51%), undergo definitive RT (30% v 20%), have higher stage disease (73% v 49% stage IV), have larger nodal size (median 3.6 vs 1.9 cm), and be less likely to have undergone resection of primary (78% v 94%). There were no differences in number of lymph nodes sampled or involved or in follow- up between the groups. Conclusion: HPV+ HNC with ECE has a favorable prognosis despite more advanced stage and larger nodal burden. Prognosis in the HPVe population with ECE remains poor despite multimodality therapy (sur- gery with CRT). ECE in the HPV+ population should be re-evaluated as a negative prognostic factor and indicator for therapeutic escalation. It is noteworthy that approximately half of HPV+ patients in our population did not receive chemotherarpy; further investigation of this is warranted, considering ongoing efforts at deintensification of therapy for this subpopulation. Author Disclosure: J.K. Russo: Employee; CHI St Alexius. Director of Clinical Research; Bismarck Cancer Center. A. Snow: None. A. Terrell: None. S.L. Mott: None. M. Laszweski: None. A. Hetland: Partner; MidDakota Clinic. Shareholder, Board Member, Chair ENT, Compensa- tion Committee, Surgery Center Committee; Mid Dakota Clinic. B. Liu: Student; Sanford Medical School. C. Fischer: None. C.M. Anderson: Research adviser, uncompensated; Galera Therapeutics. T.A. Dufan: None. J.M. Watkins: Employee; University of Iowa. 122 WITHDRAWN 123 Subsite Variation in Oropharyngeal Squamous Cell Carcinomas in the Era of Human Papillomavirus: Tonsillar Fossa Has Improved Survival Compared to Base of Tongue A. Platek, 1 V. Jayaprakash, 2 M. Platek, 2 V. Gupta, 1 D. Cohan, 1 W. Hicks, 1 T. Winslow, 3 A. Groman, 4 S.S. Dibaj, 1 H. Arshad, 1 M.A. Kuriakose, 1 G.W. Warren, 5 and A.K. Singh 2 ; 1 Roswell Park Cancer Institute, Buffalo, NY, 2 Roswell Park Cancer Institute, Buffalo, NY, United States, 3 Roswell Park Cancer Insitute, Buffalo, NY, 4 Roswell Park Cancer Institue, Buffalo, NY, 5 Medical University of South Carolina, Charleston, SC Purpose/Objective(s): Previous studies on treatment outcomes of patients with advanced oropharyngeal squamous cell carcinomas (OPSCC) have rarely analyzed subsite differences in detail in the era of human papillo- mavirus (HPV). The purpose of this study was to evaluate subsite-specific differences in survival between squamous cell carcinomas (SCC) of the base of tongue (BOT) and the tonsillar fossa (TF) in a cohort likely to have a high incidence of HPV-associated tumors. Materials/Methods: Retrospective cohort analysis utilizing data from the Surveillance, Epidemiology, and End Results (SEER) Program. The SEER cohort included 8073 primary BOT and TF SCC patients without distant metastases treated between 2004 and 2011. Primary outcome measures were subsite-based differences in overall survival (OS) and disease-specific survival (DSS). Cox proportional hazard ratios were estimated. Results: Among the 8073 primary BOT and TF SCC patients, 3705 (46%) were BOT and 4368 (54%) were TF. Median age for BOT and TF patients was 62 and 58 years, respectively. Other clinical characteristics were similar between groups, but more TF patients had poorly differentiated tumors. Overall survival with all stages combined favored TF (P< .01) and remained superior when stratified by stage. In multivariate analyses adjusted for age, gender, race, and treatment, the hazard ratio (HR) for OS was superior for TF tumors in comparison to BOT tumors across all dis- ease stages (stage I HR 1.28, 95% confidence interval [CI] 1.01-1.64; stage II HR 1.30, 95% CI 1.08-1.59; stage III HR 1.30, 95% CI 1.14-1.49; stage IV HR 1.14, 95% CI 1.00-1.30). Similar advantages were noted for DSS favoring improved outcomes for TF. Conclusion: In this large, modern cohort, OS and DSS favored outcomes in TF as compared with BOT. Further study is required to evaluate factors that influence subsite-based survival differences in TF and BOT patients in the era of HPV. Author Disclosure: A. Platek: None. V. Jayaprakash: None. M. Platek: None. V. Gupta: None. D. Cohan: None. W. Hicks: None. T. Winslow: None. A. Groman: None. S.S. Dibaj: None. H. Arshad: None. M.A. Kuriakose: None. G.W. Warren: None. A.K. Singh: None. 124 Comparisons of Dysphagia and Quality of Life (QOL) in Matched Patients with HPV-positive Oropharyngeal Cancer Receiving Chemoirradiation or Cetuximab and Irradiation S. Samuels, 1 Y. Tao, 1 T. Lyden, 1 M. Haxer, 1 M.E. Spector, 2 K. Malloy, 2 B. Carol, 1 F.P. Worden, 1 M. Schipper, 1 and A. Eisbruch 1 ; 1 University of Michigan, Ann Arbor, MI, 2 University of Michigan Comprehensive Cancer Center, Ann Arbor, MI Purpose/Objective(s): We compared functional outcomes of radiation therapy (RT) concurrent with cetuximab or with chemotherapy for matched, good prognosis patients with human papillomavirusepositive (HPV+) oropharyngeal cancer (OPC). Materials/Methods: Outcomes of patients with HPV+ OPC with minimal or no smoking history and non-T4/N3/N2C, treated on a prospective protocol of RT concurrent with cetuximab (cet-RT), were compared with similar patients on prospective chemo-RT protocols. Intensity modulated RT in all patients aimed to spare swallowing organs and salivary glands. In both groups, videofluoroscopy (VF), Common Terminology Criteria for Abstract 121; Table 1 HPV status 3-Year outcome (95% CI) Overall survival Positive 91% (74-97%) Negative 44% (25-61%) Disease-free survival Positive 91% (74-97%) Negative 40% (22-57%) International Journal of Radiation Oncology  Biology  Physics 880