(0627) Contralateral Second Primary HPV-Associated Tonsillar Squamous Cell Carcinoma

Introduction: The recommendation of prophylactic contralateral tonsillectomy for unilateral tonsillar squamous cell carcinoma (TSCC) has been debated, as HPV+ emerges as the dominant subtype. We investigated the rate of contralateral second primary HPV+ TSCC and evaluated swallowing outcomes after bilateral tonsillectomy.

Methods: We reviewed surgically resected p16+ TSCC at a tertiary institution between 2000 and 2023. Second primary rates, dysphagia outcomes, as well as morbidity and survival were assessed with multivariable regression models controlling for patient demographics, substance use, tumor multifocality and staging, extranodal, perineural, and lymphovascular invasion, neck dissection, and adjuvant radio/chemotherapy.

Results: Among 164 TSCC cases, 125 TSCC cases underwent unilateral tonsillectomy and 39 bilateral tonsillectomy (6 high-risk (preoperative workup suggestive of contralateral disease), 27 low-risk (patient/provider preference), and 6 for workup of unknown primary). Two cases of metachronous second primary TSCC (2/125 = 2%) and 3 cases of synchronous contralateral second primaries (3/39 = 8% overall; 1/27 = 4% low risk; 2/6 = 33% high-risk) were identified. Adjusting for relevant covariates, bilateral tonsillectomy did not significantly alter postoperative length of stay (4.3 vs 4 days; aβ 0.31, 95% CI ±0.56 to 1.18), probability of being discharged with soft or regular diet (68% vs 63%; aOR 1.29, 0.46-3.63), or overall survival (HR 4.38, 0.56-34.09) compared to unilateral tonsillectomy. Bilateral tonsillectomy did not result in any instances of need for G-tube.

Conclusions: Bilateral tonsillectomy does not increase morbidity compared to unilateral tonsillectomy in HPV+ TSCC, and in this study resulted in no instances of need for G-tube, and did not change hospital length of stay or survival. The rate of contralateral second primary HPV+ TSCC is notable and should be considered when discussing unilateral vs bilateral tonsillectomy.