Follow-up of low risk patients with papillary thyroid cancer: Role of neck ultrasonography in detecting lymph node metastases

Persistent or recurrent disease is rare in low risk patientswith papillary thyroid cancer, and follow-up of these patientsis a matter of debate. Neck ultrasonography (US), serum thyroglobulin(Tg), and whole body scan (WBS) after T4 withdrawalwere performed in 456 patients, followed up to 5 yr. Atthe end of the first year, 335 patients were Tg negative, and 121were Tg positive; 65 of 96 patients with Tg levels between 1 and10 ng/ml became spontaneously Tg negative after 2 yr. Duringfollow-up,WBSdiscovered node metastases in 13 subjects, andUS discovered node metastases in 38 subjects (31 Tg positiveand 7 Tg negative). WBS did not add any information, becauseall WBS-positive patients were also US and Tg positive. Fiftypercent of metastases were less than 1 cm and not palpable.Finally, the negative predictive value of both negative Tg andUS at first follow-up was 98.8%. We suggest a first follow-upbased upon US assessment and stimulated (after T4 withdrawalor recombinant human TSH) serum Tg determination;subsequently, 1) US should not be mandatory at each examinationin initially Tg- and US-negative subjects, but isstrongly suggested in all other cases; 2) Tg determinationshould be repeated 1 yr later, after exogenous or endogenousTSH stimulation only in initially Tg-positive patients withoutany other evidence of residual disease; and 3) Tg measurementduring therapy should be sufficient in all other cases.