Author(s)
Rahul Kamal Sharma, MD
Sallie M. Long, MD
Scott H. Troob, MD
Affiliation(s)
Vanderbilt University Medical Center; New York Presbyterian Hospital (Columbia Cornell Campus); Columbia University Irving Medical Center;
Abstract:
Introduction: Studies have demonstrated lymph node density (LND) to be a prognostic indicator in various malignancies, including oropharyngeal squamous cell carcinoma (OPSCC), however many do not include HPV status or are limited by small sample size. We aim to determine the association of LND on survival in HPV-positive and HPV-negative OPSCC using a national database.
Methods: Analysis of adults with OPSCC between 2010-2016 from the SEER registry. Demographic, tumor, and treatment variables were extracted. Patients with unknown lymph node yield were excluded. LND was defined as number of positive nodes divided by number of nodes extracted. Disease-specific survival (DSS) was assessed using Kaplan-Meier and log-rank statistics. Cox-regression controlling for demographic, tumor, and treatment factors was used to understand the independent effect of LND on survival.
Results: 3703 patients were analyzed, including 2855 (77%) with HPV-positive and 852 (23%) with HPV-negative OPSCC. Median LND for all patients was 0.06 (IQR 0.02-0.21). A cut-off of 0.06 was used for high vs. low LND. On Kaplan-Meier analysis, LND was associated with DSS in the overall (p<0.001) and HPV-positive (p<0.001) groups, but not in HPV-negative patients (p=0.150). On multivariate analysis controlling for age, race, sex, TNM stage, and adjuvant therapy, LND was associated with DSS in all patients (HR 1.62, 1.20-2.19, p=0.002) and HPV-positive patients (HR 2.03, 1.34-3.08, p<0.001), but not HPV-negative patients (HR 1.15, 0.71-1.86, p=0.600).
Conclusions: LND was independently associated with DSS in HPV-positive but not HPV-negative OPSCC. This is one of the largest reports of LND on outcomes in HPV-positive and HPV-negative OPSCC. Future work is needed to determine the utility of a LND threshold for risk-stratification in these tumors.