[The correlations between clinical characteristics including lesion site of papillary thyroid carcinoma and cervical...

Objective: To investigate the correlations between primary location and other clinical characteristics of papillary thyroid carcinoma (PTC) with cervical lymph node metastasis, providing evidence for optimizing surgical strategies. Methods: A total of 805 patients with unifocal PTC who underwent surgical treatment at the Sixth Medical Center of PLA General Hospital from January 1, 2015 to March 16, 2025, were included. Data on gender, age, tumor location and size, preoperative ultrasound findings, and postoperative pathological diagnosis were collected. The associations between clinical characteristics and lymph node metastasis in the central compartment (Level Ⅵ) and lateral neck (Levels Ⅱ-Ⅳ) were analyzed. Chi-square tests and multivariate logistic regression were used to identify independent risk factors for lymph node metastasis. Results: Among the 805 PTC patients, 363 (45.1%) had lymph node metastasis, including 44 (5.5%) in Level Ⅱ, 64 (8.0%) in Level Ⅲ, 79 (9.8%) in Level Ⅳ, and 345 (42.9%) in Level Ⅵ, with Level Ⅵ showing the highest metastasis rate. Multivariate logistic regression analysis revealed that male sex (OR=1.43, P=0.031), age <55 years (OR=2.02, P<0.001), tumor located in the lower pole (OR=1.88, P<0.001), and tumor size >1.0 cm (OR=3.15, P<0.001) were independent risk factors for Level Ⅵ metastasis. Male sex (OR=4.20, P=0.006) and tumor located in the upper pole (OR=6.78, P<0.001) were independent risk factors for Level Ⅱ metastasis. Tumor size >1.0 cm (OR=2.77, P=0.006) was an independent risk factor for Level Ⅳ metastasis. Age <55 years (OR=6.00, P=0.003), tumor located in the upper pole (OR=2.17, P=0.002), and tumor size >1.0 cm (OR=3.65, P<0.001) were independent risk factors for metastasis involving >5 lymph nodes. Patients with tumors in the isthmus had a significantly higher Level VI metastasis rate (85.7%, 12/14) compared to those with tumors in the thyroid lobes (42.2%, 334/791, P=0.001), and a higher rate of bilateral Level Ⅵ metastasis (35.7%, 5/14 vs. 5.1%, 40/791, P<0.001). Conclusions: Lymph node metastasis in PTC is closely associated with tumor location and size. Tumors in the lower pole primarily metastasize to Level Ⅵ, whereas those in the upper pole are more likely to metastasize to Level Ⅱ. For low-risk PTC confined to the thyroid lobe, lobectomy with isthmusectomy and central lymph node dissection is recommended. For isthmic tumors, total thyroidectomy with bilateral central lymph node dissection is advised. Male patients with upper pole tumors require careful preoperative evaluation of Level Ⅱ lymph node involvement. For patients aged <55 years with tumors >1.0 cm in the upper pole, individualized treatment strategies should be formulated based on additional high-risk factors.