Author(s)
Edgar Ochoa, BS
Gaelen B. Stanford-Moore, MD
Mary Han, BA
Andrew R. Larson, MD
Kathryn R. Hoppe, MD
William R. Ryan, MD
Affiliation(s)
University of California-San Francisco, Department of Otolaryngology/Head and Neck Surgery
Abstract:
Educational Objective: At the conclusion of this presentation, the participants should be able to describe neck level distributions of metastatic nodal disease and risk factors for occult nodal disease in human papilloma virus associated oropharynx squamous cell carcinoma. Objectives: For human papilloma virus associated oropharynx squamous cell carcinoma (HPV+OPSCC), we evaluated the neck level lymph node (LN) metastasis distribution based on postsurgical histopathology and the incidence of and risk factors for occult LN metastases as these patterns need specific clarification for this newer cancer subset. Study Design: Retrospective National Cancer Database (NCDB) review. Methods: We analyzed 2,364 NCDB HPV+OPSCC patients who underwent neck dissection (ND) from 2010-2015. Incidence and distribution of LN metastases were calculated for neck levels 1-5. Variables associated with occult LN metastasis were assessed by multivariate logistic regression. Results: Positive LNs in therapeutic NDs were found in level 1: 9.0% (175/1940), level 2: 81.1% (1573/1940), level 3: 29.6% (575/1940), level 4: 11.9% (230/1940), and level 5: 5.0% (97/1940). Occult LNs were identified in 35.8% (152/424) of cN0 patients. Occult LN metastases in elective NDs were found in level 1: 3.3% (14/424), level 2: 26.9% (114/424), level 3: 8.7% (37/424), level 4: 4.0% (17/424), and level 5: 0.2% (1/424). The presence of occult LNs was independently associated with lymphovascular invasion (OR, 6.94; 95% CI, 3.65-13.72; p<0.001) and positive surgical margins (OR, 1.51; 95% CI, 1.05-2.24; p=0.019). Occult LN metastases were not significantly associated with: cT stage, pT stage, primary site (tonsil vs base of tongue), nor the number of LNs resected. Conclusions: For HPV+OPSCC, occult nodal disease is common. Therapeutic NDs should encompass at least levels 2, 3, and 4, and possibly 1, whereas elective NDs should at least encompass levels 2 and 3.