Clinicians should consider it essential to evaluate survival status after surgery for patients with medullary thyroid carcinoma (MTC) using postoperative lymph node (LN) information. The N status from the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system is widely used in clinical practice.
1 However, N status includes only information on the location of LNs according to the pathologic results. The number of positive LNs (PLNN) is reported to be a prognostic factor of MTC.
2 But only analyzing PLNN to predict prognosis may cause bias if the surgical resection of LNs is inadequate. Furthermore, the lymph node ratio (LNR) of the PLNN to the number of removed LNs has been introduced and confirmed as a predictive factor of MTC survival, but its application might be limited because some MTC patients have N0 status.
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