Delphian lymph node metastasis predicts occult contralateral carcinoma for unilateral papillary thyroid carcinoma patients with contralateral benign nodules

For unilateral PTC patients with benign nodules in the contralateral lobe evaluated preoperatively, the necessity of total thyroidectomy remains controversial. This study aimed to investigate the predictive factors for occult contralateral carcinoma and whether DLN metastasis could predict it.A total of 148 patients with unilateral PTC and contralateral benign nodules who were treated with a near-total thyroidectomy or TT at a single institution between August 2018 and April 2020 were enrolled. Clinicopathological features such as age, sex, TgAb or TPOAb level, primary tumor location, nodule number in contralateral lobe, carcinoma number in primary lobe, tumor size, capsular invasion, central lymph node metastasis, DLN metastasis were analyzed to investigate the rate and predictive factors of occult contralateral carcinoma.44.6% patients were diagnosed with occult contralateral thyroid carcinoma. Univariate analysis showed that sex (P = 0.008), mulifocality of primary carcinoma (P < 0.001), tumor size (P = 0.033), capsular invasion (P = 0.042), CLN metastasis (P = 0.004), DLN metastasis (P = 0.001) were associated with occult contralateral carcinoma. Multivariate analysis showed that multifocality of primary carcinoma (p = 0.000, OR = 9.729), DLN metastasis (p = 0.042, OR = 4.701), capsular invasion (p = 0.022, OR = 2.909), and male patients (p = 0.006, OR = 3.926) were all independent predictive factors.For unilateral PTC patients with benign nodules in the contralateral lobe evaluated preoperatively, multifocality of primary carcinoma, DLN metastasis, capsular invasion, and male patients are independent predictors of occult contralateral carcinoma. We suggest separate excision and frozen section of DLN intraoperatively, if DLNs were confirmed metastasized, a TT was highly recommended.