Abnormal carcinoembryonic antigen levels and medullary thyroid cancer progression - A multivariate analysis

Hypothesis: Medullary thyroid cancer cells are capable of secreting carcinoembyronic antigen (CEA). An abnormal preoperative CEA level may have important implications for the management of this condition. Design: Retrospective analysis. Setting: Tertiary referral center at a university hospital. Patients: One hundred fifty patients with a histopathologic diagnosis of medullary thyroid cancer and preoperative CEA measurements using the same assay. Main Outcome Measure: We used univariate and multivariate analyses to quantify the relationship between preoperative CEA level and tumor progression. Results: On multivariate analysis, abnormal preoperative CEA levels were significantly associated with the initial operation rather than reoperation, larger primary tumors, positive lymph nodes, and distant metastasis. When analyses were limited to the 54 patients with increased CEA levels before the initial operation, there was a respective significant association between successive CEA levels (4.7-10.0, 10.1-30.0, 30.1-100.0, and >100.0 ng/mL) and lymph node metastases (>10 positive nodes: 0%, 9%, 53%, and 69% [P<.001]), involvement of cervical lymph node compartments (central: 33%, 36%, 73%, and 93% [P=.002]; lateral [ipsilateral]: 20%, 27%, 67%, and 88% [P=.001]; and lateral [contralateral]: 22%, 10%, 36%, and 73% [P=.008]), and distant metastasis (0%, 27%, 13%, and 75% [P<.001]). When CEA levels exceeded 30.0 ng/mL, surgical cure was exceptional. Conclusions: In medullary thyroid cancer, an abnormal CEA level heralds advanced disease. Carcinoembryonic antigen levels greater than 30.0 ng/mL indicate central and lateral (ipsilateral) lymph node metastases, whereas CEA levels greater than 100.0 ng/mL signify lateral (contralateral) lymph node metastases and distant metastasis.