Clinical outcome and influencing factors of differentiated thyroid cancer with biochemical incomplete response

The aim of our study was to investigate the clinical outcomes and predictive factors in patients with biochemical incomplete response (BIR) after initial radioiodine therapy (RAI).

This retrospective study enrolled 198 patients with BIR from two institutions and stratified them into a training cohort (Qingdao cohort, n = 144) and an external validation cohort (Beijing cohort, n = 54). The patients were classified as having incomplete response (IR) or non-IR disease at the final follow-up. Univariate and multivariate analyses identified IR predictors in the training cohort. A nomogram was developed using the training cohort and was validated in the validation cohort using calibration curves, decision curve analysis (DCA), and receiver operating characteristic analysis.

Age, recurrence risk, pre-stimulated thyroglobulin (ps-Tg), and BRAF^V600E mutation were independent predictors of IR in the training cohort. The nomogram identified ps-Tg as the strongest predictor of IR risk, followed by the BRAF^V600E mutation, age, and recurrence risk. The calibration curves demonstrated excellent agreement between the predicted and observed probabilities. DCA confirmed favorable clinical utility.

This validated nomogram provides a clinically useful tool for quantifying IR risk in BIR patients, supporting personalized management decisions after initial RAI.