IMPACT OF LYMPH-NODE METASTASIS IN DIFFERENTIATED CARCINOMA OF THE THYROID - A MATCHED-PAIR ANALYSIS

Background. Cervical lymph node metastasis in differententiated thyroi d carcinoma has mostly been found to have little relationship to progn osis. However, some studies report nodal involvement to be an adverse factor, while others have found it to be favorable. We have undertaken a matched-pair analysis of previously untreated patients, with and wi thout ipsilateral neck metastasis, to examine the significance of noda l spread in patients with otherwise equivalent prognostic factors for differentiated thyroid cancer. Method. From a database of 931 patients , treated from 1930 to 1980, we used a computer to match patients with confirmed lateral neck metastasis (N1) to those who were stage NO, an d had the following identical prognostic factors: no distant metastasi s, age (within 4 years), and tumor size, histology, and intrathyroidal extent. When possible, matches were also made for gender, multifocali ty, and extent of thyroid surgery. Survival and treatment failures wer e analyzed, with and without stratification for age. Results. We were able to select 100 N1 patients with corresponding NO patients, sharing the major prognostic risk factors as listed. Overall, there was no di fference in survival, although N1 patients more often had recurrence. Mortality increased with age. Analysis at high-risk age (45 years and older) showed significantly more recurrences in N1 patients (p = .008) . Twenty-year survival in N1 patients over the age of 45 was lower tha n that of NO patients. On the other hand, under the age of 45, N1 pati ents had better survival. These differences, however, did not reach st atistical significance. Conclusion. Nodal involvement in older patient s with thyroid cancer increases the risk of recurrence, although no si gnificant difference in survival is observed in relation to age. (C) 1 996 John Wiley & Sons, Inc.