Table 5.

Predictive factors reported in previous studies.

Author	Type	Age	Cytological type	Tumor size	T stage	ETE	Lymphovascular invasion	Reoperation	Central neck involvement	Lateral neck involvement	Bilateral cervical metastasis	Distant metastasis
Woo et al. [6]	PTC		X	X	X	X	X	√	√	√
Moritani [7]	PTC	√							√
Liu et al. [10]	PTC	X			X				X	X	√	√
Machens and Dralle [11]	PTC											√
Choi et al. [14]	PTC			√			√			√
Machens and Dralle [15]	PTC	√	√	X		√					√	√
Machens et al. [18]	MTC					√		√			√	√
Buhr et al. [23]	MTC				√						√
Sugenoya et al. [22]	DTC				√						√
Ducic and Oxford [16]	Thyroid					√			√
Machens et al. [20]	PTC, MTC		√	√				√

√ stands for the factor that was proved to have predictive value of the mediastinal lymph node metastasis in thyroid carcinoma; X stands for the factor that was proved to have no predictive value of the mediastinal lymph node metastasis in thyroid carcinoma. ETE: extrathyroidal extension.