Risk factors for central lymph node metastasis in papillary thyroid microcarcinoma: a simplified risk scoring system

Background Central lymph node metastasis (CLNM) occurs in 20–50% of papillary thyroid microcarcinoma (PTMC) patients and influences surgical decision-making. Existing predictive models require complex calculations or specialized tools, limiting clinical utility. This study aimed to develop a simplified risk scoring system for preoperative CLNM prediction using readily available clinical variables. Methods This retrospective cohort study included 486 PTMC patients who underwent thyroid surgery with prophylactic central neck dissection between January 2022 and January 2026. Multivariate logistic regression identified independent predictors of CLNM. A simplified risk scoring system was developed by multiplying regression coefficients (β) by 2 and rounding to integers. Internal validation was performed using bootstrap resampling (1000 iterations). Results Four independent predictors were identified: male gender (β=0.52, adjusted OR 1.68, 95% CI 1.12–2.53), tumor size >5 mm (β=0.76, adjusted OR 2.14, 95% CI 1.45–3.16), multifocality (β=0.64, adjusted OR 1.89, 95% CI 1.23–2.91), and extrathyroidal extension (β=1.02, adjusted OR 2.76, 95% CI 1.68–4.53). The scoring system assigned 1 point each for male gender and multifocality, and 2 points each for tumor size >5 mm and extrathyroidal extension (total score 0–6). The apparent AUC was 0.742 (95% CI 0.698–0.786), with optimism-corrected AUC of 0.738. Risk stratification demonstrated progressive CLNM rates: very low-risk (score 0, 0%), low-risk (score 1, 22.3%), intermediate-risk (scores 2–3, 34.6%), and high-risk (scores 4–6, 62.2%) (p for trend Conclusions This simplified four-variable scoring system effectively stratifies CLNM risk in PTMC using preoperatively available data. Patients with score ≤1 may be considered for less extensive surgery or active surveillance, while those with score ≥4 should be considered for prophylactic central neck dissection. This practical tool enables immediate bedside risk assessment without specialized software, though external validation is warranted.