The impact of lymph node involvement on survival in patients with papillary and follicular thyroid carcinoma

Background. The prognostic role of lymph node metastases in well-differentiated thyroid carcinoma remains controversial. We investigated impact of lymph node involvement on survival in patients with well-differentiated thyroid cancer. Methods. We queried the Surveillance, Epidemiology, and End Results registry for patients diagnosed with well-differentiated thyroid carcinoma between 1988 and 2003. Cases were stratified by age (<45 vs >= 45 years) and pathology (Papillary/follicular). Four separate Cox regression models were developed to test the effects of demographic and clinical covariates on survival. Results. We identified 33,088 patients. 30,504 patients (49% >= 45 years) had papillary carcinoma and 2,584 patients (55% >= 45 years) had follicular carcinoma. Age affected survival in all models (P < .001). In. patients with papillary carcinoma <45 years, lymph node disease did not influence survival (P = .535), whereas in patients >= 45 years, lymph node involvement was associated with 46% increased,risk of death (P <. 001). In, patients with follicular carcinoma, Lymph node involvement conferred increased risk of death in both age groups (P <= .002). Effects of other covariates varied between models. Conclusion. Cervical lymph node metastases conferred independent risk in all patients with follicular carcinoma and in those patients with papillary carcinoma aged >= 45 years, but did not affect survival in patients with papillary carcinoma <45 years. (Surgery 2008; 144: 1070-8.)