Risk‐Stratified Bilateral Tonsillectomy for Unilateral HPV ‐Associated Tonsillar SCC : Oncologic and Functional Outcomes From a Single Institution

Objective To characterize synchronous and metachronous contralateral second primary malignancy (SPM) rates across preoperatively defined risk strata in patients with HPV‐positive tonsillar squamous cell carcinoma (TSCC) undergoing unilateral versus bilateral tonsillectomy and to evaluate associated postoperative morbidity and functional outcomes. Methods All patients with HPV‐positive TSCC who underwent surgery between 2000 and 2023 were retrospectively reviewed. Fisher's exact test, Kaplan–Meier analysis, and log‐rank tests were used to compare morbidity and survival, and multivariable regression models were employed to control for confounders, including patient demographics, substance use, tumor staging, and adjuvant therapy. Results From 163 patients, 123 (75.5%) underwent unilateral tonsillectomy, 30 (18.4%) low‐risk bilateral tonsillectomy, and 10 (6.1%) high‐risk bilateral tonsillectomy. Across all patients undergoing bilateral tonsillectomy, synchronous tonsillar SPMs were identified in 10.0%, with rates of 6.7% in the low‐risk bilateral group and 20.0% in the high‐risk bilateral group. Of the 123 patients who underwent unilateral tonsillectomy, 0.8% developed a metachronous contralateral TSCC at 181.6 months. Among low‐risk bilateral patients undergoing prophylactic contralateral tonsillectomy, the NNT for identification of one occult synchronous SPM was 14 (95% CI: 5–50). Bilateral tonsillectomy did not significantly alter discharge diet, postoperative length of stay, hemorrhage rates, return to the operating room, or 30‐day emergency department visits. Disease‐free survival did not differ significantly across risk‐stratified groups. Conclusion Contralateral second primary TSCC clustered disproportionately among high‐risk patients. Bilateral tonsillectomy was not associated with significantly increased postoperative morbidity. These findings support a selective, risk‐stratified approach to bilateral tonsillectomy in HPV‐associated TSCC, balancing the potential benefit of occult contralateral disease detection against procedure‐related morbidity through shared decision‐making. Level of Evidence III.