Tumor and Flap Reconstruction Volumes and Functional Outcomes after Glossectomy.

[IMPORTANCE] Oral tongue is the most common subsite of oral cavity cancers, and incidence is increasing. Tongue resection is associated with morbidity, affecting speech, swallowing, and quality of life.

[OBJECTIVE] To assess the association of tumor volume and extent of tongue resection with functional outcomes.

[DESIGN, SETTING, AND PARTICIPANTS] Patients with squamous cell carcinoma who underwent surgical resection of the oral tongue at a tertiary-level academic institution between 2014 and 2025 were included in this retrospective cohort study. Demographic, tumor, treatment, and postoperative outcomes measured with validated instruments were identified.

[EXPOSURE] Partial or hemiglossectomy (PG) vs total or subtotal glossectomy (TG).

[MAIN OUTCOMES AND MEASURES] Functional Oral Intake Scale (FOIS) score of 3 or lower, indicating gastrostomy tube dependency. Multivariable analysis assessed risk factors for the primary outcome. Radiographic volumetric analysis of tumor, tongue, and flap volumes was performed. Linear and nonlinear regression modeling assessed the association between measured volumes and functional outcomes.

[RESULTS] Of 357 patients (median age 62.3 [range, 18-95] years; 51.0% female), 88.2% [n=315] had PG and 11.8% [n=42] had TG. Tumors were classified as T1 or T2 in 71.2% of patients (254 of 357) and as T3 or T4 in 28.8% (103 of 357). Free-flap reconstruction was performed in 150 (42.0%) patients, and 186 (52.1%) received adjuvant radiation. Median follow-up was 36.1 (IQR, 18.2-65.6) months. The TG cohort had worse median FOIS score (2 [IQR, 1-5] vs 5 [IQR, 4-6]), aspiration (3 [IQR, 2-5] vs 1 [IQR, 1-2]), tongue strength (17 [IQR, 15-20] vs 36 [IQR, 25-42]), tongue range of motion (16 [IQR, 0-25] vs 88 [IQR, 63-100]), speech understandability (50 [IQR, 50-75] vs 100 [IQR, 100-100]), and patient-reported quality of life (67 [IQR, 60-71] vs 77 [IQR, 65-86]). On multivariable analysis, older age, current or former smoking status, use of free flap, TG, and greater resection volume were associated with FOIS score of 3 or lower. Preoperative tumor fraction greater than 31% and resection volume fraction greater than 67% were associated with the outcome of FOIS score of 3 or lower, indicating gastrostomy tube dependence. Preoperative tumor fraction greater than 26% and resection volume fraction greater than 58% were associated with understandability of speech score lower than 75, indicating poorly intelligible speech. On nonlinear regression analysis, tongue volume restoration to 100% of baseline value was associated with improved oral intake.

[CONCLUSIONS AND RELEVANCE] In this study, volumetric analysis demonstrated that tumor, resection, flap, and total tongue volumes were associated with speech and swallow outcomes. These findings suggest that quantitative knowledge of incremental changes in tongue resection and restoration may contribute to improved preoperative counseling and functional outcomes.