Impact of Postoperative Neck Radiotherapy Volumes on Long-Term Unstimulated Saliva Flow Following Primary Surgery and Ipsilateral Neck Dissection for Oral Cavity Squamous Cell Carcinoma.

Abstract

We investigate the association of postoperative radiotherapy (PORT) volumes and salivary function in oral cavity SCC (OSCC). OSCC patients undergoing PORT 2005-2021 underwent modified Schirmer test (MST) pre-PORT, 6 and/or 12 months post-PORT. Hyposalivation rates were compared by PORT volumes. MVA identified predictors for chronic hyposalivation. Among 165 eligible patients, 88 (53%) received bilateral, 66 (40%) ipsilateral, and 11 (7%) no-neck (primary-only) PORT. Baseline characteristics were similar, except more N2b/N2c disease received bilateral PORT vs. ipsilateral or no-neck (60% vs. 36% vs. 0%, p < 0.001). Baseline hyposalivation was similar (26% vs. 30% vs. 18%, p = 0.67). Hyposalivation occurred more frequently in bilateral vs. ipsilateral vs. no-neck PORT at 6 (90% vs. 62% vs. 9%) and 12 months (90% vs. 48% vs. 0%) (both p < 0.001). On MVA, bilateral neck PORT and smoking predicted chronic hyposalivation. Increasing PORT volumes predict saliva function recovery and chronic hyposalivation, informing treatment discussions.