Jc. Sisson et al., Serum thyroglobulin levels after thyroxine withdrawal in patients with lowrisk papillary thyroid carcinoma, THYROID, 10(2), 2000, pp. 165-169
We hypothesized that elevated levels of serum thyroglobulin (Tg) are freque
ntly found as the only index of residual neoplasm in patients with low-risk
papillary thyroid carcinoma. The records of patients operated on for papil
lary thyroid carcinoma over a 2-year period were reviewed, and the patients
were allocated to risk groups by a validated staging method that does not
include Tg levels. Of the 35 patients who manifested a low-risk carcinoma,
9 (26%) exhibited elevated Tg concentrations (11-53 ng/mL) during thyroxine
withdrawal after therapies, while clinical, scintigraphic, and radiographi
c studies at least 1 year later showed no evidence of tumor. Prior scintigr
aphic imaging of therapeutic doses of I-131 in 8 of 9 patients demonstrated
no distant metastases, further confirming the low-risk status of this grou
p. The staging method predicts that only 0.9% of patients with low-risk pap
illary carcinoma will have a cause specific death in 20 years. Elevated Tg
concentrations have not been shown to forecast independently the survival o
f patients with low-risk papillary carcinoma. Thus, although frequently enc
ountered, elevated Tg concentrations are unlikely to predict shortened surv
ival in patients with papillary carcinoma for whom low risk has been determ
ined from other data.