Regional metastases in well-differentiated thyroid carcinoma: pattern of spread.

OBJECTIVES/HYPOTHESIS To determine the pattern of spread of WDTC to regional lymph nodes, in patients who presented with clinically positive nodes. STUDY DESIGN Retrospective chart review. MATERIALS AND METHODS Between October 2001 and December 2006, a total of 27 consecutive patients (12 males, 15 females) with clinical evidence of cervical metastasis of well-differentiated thyroid carcinoma (WDTC) underwent 28 neck dissections (ND) with a mean follow-up 33.7 months. Papillary carcinoma was found in 24 patients and follicular carcinoma in 3. All neck dissection specimens were separated during surgery into levels, and analysis was done with respect to the levels of the neck. Clinical and demographic parameters were correlated to the pathologic parameters, including number of pathologic nodes, size of tumor, and the patient's age, with univariate and multivariate analysis. RESULTS The mean number of pathologic nodes in ND specimen was 6.7. The predominant site of metastasis was level VI (95%), followed by level III (68%), level IV (57%), and level II (54%). Metastases above the XI nerve were found in 7% of the patients. Level V showed 20% of nodal metastasis. A correlation was found between size of primary tumor and number of positive pathologic lymph nodes (P = .02) and an inverse correlation between the age of the patient and the number of pathologic nodes (P = .043). CONCLUSIONS The high incidence of metastatic disease in levels II through VI supports the recommendation for posterolateral and anterior ND in patients with WDTC and clinically positive nodes. The correlation between tumor size, the age of the patient, and the number of positive nodes is an interesting finding that warrants further study.