Development and Internal Validation of a Competing‐Risk Nomogram for Predicting Cancer‐Specific Death in Oral Cavity Squamous Cell Carcinoma

OBJECTIVE: Oral cavity squamous cell carcinoma (OCSCC) patients face competing risks of cancer and non-cancer death. This study developed and internally validated a competing-risk nomogram for cancer-specific death. METHODS: A total of 84,456 SEER 17-registry adults (age ≥ 20 years) with OCSCC (2000-2023) were identified. A Fine-Gray model was fit on a 70% training split, with backward elimination of nine candidate predictors (gender retained a priori). The nomogram, predicting 3- and 5-year cancer-specific death, was evaluated on the 30% test set against a stage-only benchmark, with Cox sensitivity analyses. RESULTS: The final model retained age, race, subsite, grade, stage, surgery, radiation and gender. Distant (vs. localized) stage (sHR 3.48, 95% CI: 3.30-3.66) and surgery (sHR 0.48, 95% CI: 0.46-0.50) were the strongest predictors. Time-dependent AUC was 0.777 (3-year) and 0.765 (5-year), 5-6 points above the stage-only model (p < 0.001), with good calibration and Brier scores better than a null model (p < 0.001). Proportional-hazards assumptions were violated (p < 0.001), so estimates are time-averaged; radiation's estimated direction differed between Fine-Gray and Cox models, likely reflecting confounding by indication. CONCLUSION: This competing-risk nomogram provides individualized, reasonably well-calibrated 3- and 5-year cancer-specific death risk estimates for OCSCC. External validation is needed before clinical use.