title: Papillary thyroid carcinomas with biochemical incomplete or indeterminate responses to initial treatment: repeat stimulated thyroglobulin assay to identify disease-free patients.
abstract: Papillary thyroid cancer (PTC) patients treated with thyroidectomy and radioiodine remnant ablation (RRA) often have detectable TSH-stimulated thyroglobulin (Tg) levels without localizable disease after primary treatment. To assess the value of repeat stimulated Tg assays in these patients' follow-up, we retrospectively analyzed 86 cases followed in 5 Italian thyroid-cancer referral centers. We enrolled 86 patients with PTCs treated with total/near-total thyroidectomy plus RRA between January 1,1990 and January 31, 2006. In all cases, the initial postoperative visit revealed stimulated serum Tg ≥1 ng/mL, negative Tg antibodies, and no structural evidence of disease. None received empiric radioiodine therapy. Follow-up (median: 9.6 years) included neck ultrasound and basal Tg assays (yearly) and at least 1 repeat stimulated Tg assay. Of the 86 patients analyzed (initial risk: low 63 %, intermediate 35 %, high 2 %), one (1 %) had ultrasound-detected lymph node disease and persistently elevated stimulated Tg levels at 3 years. In 17 (20 %), imaging findings were consistently negative, but the final stimulated Tg levels was still >1 ng/mL (median 2.07 ng/mL, range 1.02-4.7). The other 68 (80 %) appeared disease-free (persistently negative imaging findings with stimulated Tg levels ≤1 ng/mL). Mean intervals between first and final stimulated Tg assays were similar (5.2 and 4.8 years) in subgroups with versus without Tg normalization. Reclassification as disease-free was significantly more common when initial stimulated Tg levels were indeterminate (<10 ng/mL). In unselected PTC cohorts with incomplete/indeterminate biochemical responses to thyroidectomy and RRA, periodic remeasurement of stimulated Tg allows most patients to be classified as disease-free.
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Livia
authors.initials: L
authors.lastname: Lamartina
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Montesano
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Trulli
authors.affiliation: Unità Operativa di Endocrinologia, Azienda Ospedaliera Ospedali Riuniti Villa Sofia-Cervello, 90146, Palermo, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Attard
authors.affiliation: Unità Operativa di Endocrinologia, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza, 71013, San Giovanni Rotondo, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Torlontano
authors.affiliation: Unità di Endocrinologia, Ospedale di Tinchi-Pisticci, 75020, Matera, Italy.
authors.forename: Rocco
authors.initials: R
authors.lastname: Bruno
authors.affiliation: Unità Operativa Semplice Dipartimentale di Endocrinologia, Ospedale di Bentivoglio, 40010, Bologna, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Meringolo
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Università di Pisa, 56126, Pisa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Monzani
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Università di Catania, 95123, Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Tumino
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ronga
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Maranghi
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Biffoni
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy. sebastiano.filetti@uniroma1.it.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Filetti
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Dipartimento di Scienze Chirurgiche, Università di Roma Sapienza, Viale del Policlinico, 155, 00161, Rome, Italy.
authors.forename: Cosimo
authors.initials: C
authors.lastname: Durante
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood; D002291:Carcinoma, Papillary / Q000097:blood* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000175:diagnosis*; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; D013954:Thyroglobulin
keywords: Biochemical incomplete response; Follow-up; Indeterminate response; Papillary thyroid cancer; Recurrences; Thyroglobulin