Nomogram to predict the prognostic value of tumor deposits for patients with papillary thyroid carcinoma.

Background: Tumor deposits (TDs), nodules in the peritumoral adipose tissue with no architectural residue of lymph node, have previously been described in colorectal adenocarcinomas with poor prognosis. However, the significance of TD has not been fully investigated in patients with papillary thyroid carcinoma (PTC). Method: We retrospectively enrolled 541 patients undergoing surgery between 2015 and 2021. The patients were classified into two groups according to TD status (TD vs non-TD), and the clinicopathologic characteristics and disease-free survival (DFS) were compared. Associations of TD presence with other clinicopathologic factors were evaluated by logistic regression analysis. Univariate and multivariate Cox regression analyses were performed to determine the primary cohort's prognostic factors for DFS. A nomogram was constructed for clinicians as a quantitative tool for estimating DFS. Result: In our cohort, TD were identified in 16.1% of patients and had higher rate of aggressive features, including microscopic and gross extrathyroidal extension, invasion of the recurrent laryngeal nerve and esophagus, prevertebral fascia involvement or encasement of the carotid artery/internal jugular vein, extranodal extension, advanced clinical stage, tumor recurrence and distant metastasis (all P < 0.05). Univariate and multivariate Cox regression analyses confirmed TD as an independent prognostic factor for DFS, with a 2.501-fold increased risk of recurrence (P < 0.001). The nomogram, incorporating TD and other significant factors, demonstrated good discrimination and calibration (C-index = 0.79). Conclusion: The presence of TD was significantly associated with poor prognosis in PTC patients. TD showed promising efficacy as a potential prognostic indicator for PTC patients.