Preoperative determination of serum thyroglobulin may identify patients with differentiated thyroid cancer who might recur without increased thyroglobulin
B Gibelli1, N Tradati1, P Tredici1, C De Cicco2, L Bodei2, MT Sandri3 & F Chiesa1
Thyroglobulin is generally a reliable marker of recurrent disease in patients with well differentiated thyroid carcinoma. However, some patients have recurrent disease but no increase in serum thyroglobulin. In order to try to identify patients who might recur with no such sign of the disease, we preoperatively assessed thyroglobulin levels in 185 consecutive patients scheduled for primary treatment for well differentiated thyroid carcinoma from June 1997 to May 2002 at the Head and Neck Division of the European Institute of Oncology. We found 22 patients (11.9% of the total) in whom serum thyroglobulin was undetectable. Thyroglobulin antibodies were present in 11 at diagnosis and decreased slowly after surgery, but in all 22 cases thyroglobulin was never detected in the follow-up, either during thyroxin suppressive therapy or during withdrawal for radioiodine scan. One of these low-thyroglobulin patients developed recurrent disease involving the cervical lymph nodes, with positive radioiodine scan, and thyroglobulin remained undetectable.
Among patients with normal or high thyroglobulin prior to treatment, this fell to very low levels in all cured cases. In the 16 patients with high thyroglobulin that recurred, the recurrence was indicated by increase in thyroglobulin levels in all cases.
We conclude that thyroglobulin is a useful and reliable marker of disease progression or persistence in most patients with differentiated thyroid carcinoma. Preoperative assessment of serum thyroglobulin may identify patients who might recur without increased thyroglobulin, in whom follow-up by monitoring thyroglobulin serum levels is inadequate.