Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
BACKGROUND: Elective treatment of the contralateral uninvolved neck in patients with HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) has generally involved whole-neck irradiation (WNI) encompassing level II-IV nodal stations. Numerous studies evaluating reductions in radiotherapy dose or volume in HPV+ OPSCC patients have reported improved patient-reported quality of life scores, but few have examined the effects on objective swallowing outcomes. Here, we compare changes in swallowing kinematics in HPV+ OPSCC patients undergoing primary chemoradiation (CRT) who received elective upper-neck irradiation (UNI) sparing the uninvolved lower neck versus whole-neck irradiation (WNI).
METHODS: Patients with newly diagnosed HPV+ OPSCC treated with primary CRT between November 2015 and October 2023 were retrospectively reviewed. Patients with N0-N1 (AJCC 8th edition) disease were considered for elective UNI if PET imaging and/or biopsy determined the contralateral neck to be clinically uninvolved. All patients who underwent a baseline videofluoroscopic swallow study (VFSS) prior to treatment and at least two VFSSs after CRT were included. A minimum of at least 6 months of VFSS follow-up assessments was required to be included for analysis. The primary comparison of interest was dynamic swallowing kinematic measures derived from VFSS (as developed by Rebecca Leonard) between UNI and WNI. Secondary comparisons included changes in functional oral intake scale (FOIS), changes in penetration-aspiration scale (PAS), rates of feeding tube placement (either nasogastric or gastrostomy) during/after treatment, hospitalizations for aspiration pneumonia, regional neck recurrence, and post-CRT esophageal dilations. Chi-square and t-tests were used to compare categorical and continuous covariates between groups, with p-values <0.05 considered statistically significant. Adjustment for N-stage was accomplished via multivariable linear regression.
RESULTS: Thirty-four patients met criteria, 18 receiving contralateral elective UNI and 16 receiving elective WNI. At baseline, age, tumor subsite distribution, T-stage, radiation prescription dose, and pre-CRT PAS were well-balanced between UNI and WNI groups. However, UNI had overall lower N-stages (p=0.013) and higher mean baseline FOIS (6.6 vs. 5.6, p=0.049) than WNI. At the latest follow-up assessment, WNI demonstrated a significant worsening in PAS from baseline compared to UNI (+2.4 vs. +0.4, p=0.020). Between WNI and UNI, there were significant differences between mean changes in kinematic measures of the pharyngeal constriction ratio (PCR; +0.093 vs. +0.011, p=0.025) and sum of maximal hyoid displacement plus hyoid-to-larynx distance (Hmax + HL; -6.1 vs. +0.8, p=0.038). After adjusting for N-stage, the association between WNI and worse Hmax + HL remained statistically significant (p=0.037), but not PCR (p=0.059) or PAS (p=0.093). There were no significant differences in changes in FOIS or other kinematic variables analyzed. Among secondary outcomes, UNI required feeding tube placement less frequently than WNI (22% vs. 75%, p=0.002), with no difference in rates of esophageal dilation, hospitalizations for pneumonia, or regional nodal recurrence between groups. Three patients experienced distant metastatic recurrences, all in the WNI group.
DISCUSSION: Elective UNI of the contralateral uninvolved neck was associated with better objective swallowing measures (VFSS kinematics, PAS, and feeding tube utilization) compared to WNI in CRT-treated HPV+ OPSCC patients. A prospective comparison of these metrics between UNI and WNI is warranted.