Long-term surveillance of papillary thyroid cancer patients who do not undergo postoperative radioiodine remnant ablation: is there a role for serum thyroglobulin measurement?
BACKGROUND
Serum thyroglobulin (Tg) assays are considered fundamental in postoperative surveillance of differentiated thyroid cancer (DTC) patients. However, the postsurgical profile of Tg levels has never been specifically investigated in patients who do not undergo radioiodine remnant ablation (RRA).


OBJECTIVE
Our objective was to explore the evolution of Tg levels over time in DTC patients treated with total or near-total thyroidectomy without RRA.


METHODS
We retrospectively analyzed 290 consecutively diagnosed cases of low-risk (American Thyroid Association criteria) DTC treated with thyroidectomy alone and followed yearly with neck ultrasonography and serum Tg assays. We compared final Tg values in this group and a matched group of 495 RRA-positive patients. Temporal trends of serial Tg levels were also analyzed in 78 of the RRA-negative patients monitored with a high-sensitivity immunoradiometric assay.


RESULTS
After follow-up of 2.5-22 yr (median 5 yr), final Tg levels were undetectable (<1 ng/ml) in 274 of 290 RRA-negative patients (95%) and 492 of 495 RRA-positive controls (99%). In the subset of 78 RRA-negative patients, undetectable Tg levels (<0.2 ng/ml) were recorded in 60% at the first postoperative evaluation (3-12 months) and in 79% after 5 yr. Tg levels increased in the single patient who experienced disease recurrence during the observation period.


CONCLUSIONS
In most RRA-negative patients, postoperative serum Tg values spontaneously drop to undetectable levels within 5-7 yr after thyroidectomy. Thus, in later phases, Tg assays may be a valuable tool for follow-up even in patients who do not undergo RRA.
Dipartimento di Medicina Interna e Specialità Medica, Università di Roma Sapienza, Rome, Italy.
Cosimo
C
Durante
Teresa
T
Montesano
Marco
M
Attard
Massimo
M
Torlontano
Fabio
F
Monzani
Giuseppe
G
Costante
Domenico
D
Meringolo
Marco
M
Ferdeghini
Salvatore
S
Tumino
Livia
L
Lamartina
Alessandra
A
Paciaroni
Michela
M
Massa
Laura
L
Giacomelli
Giuseppe
G
Ronga
Sebastiano
S
Filetti
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma; D002291:Carcinoma, Papillary; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood / Q000532:radiotherapy / Q000601:surgery*; D013965:Thyroidectomy
D007457:Iodine Radioisotopes; D013954:Thyroglobulin