Papillary Thyroid Microcarcinoma: Clinicopathological Features and Prognosis Factors

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 459-496-Thyroid Neoplasia & Case Reports
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-485
Pedro Marques*, Daniel Macedo, Joana Simões Pereira, Margarida da Silva Vieira, Rita Santos, Valeriano Leite and Maria João Bugalho
Portuguese Institute of Oncology, Lisbon, Portugal
Introduction: There is debate concerning the clinical significance and management of papillary thyroid microcarcinoma (PTMC). The purpose of this study was to analyze clinicopathological features of PTMC trying to identify significant risk/prognostic factors.

Methods: Retrospective analysis of clinical files of PTMC patients diagnosed within 2002-2006, and followed at the Endocrinology Department of Portuguese Institute of Oncology, Lisbon. Patients were identified through South Regional Cancer Registry.

Results: 111 PTMC were identified. The mean age at diagnosis was 47,1 years (±15,3); 91(82%) were female (F/M=4,6:1). 52(46,9%) had a cytological diagnosis prior to surgery. All had surgery, mostly (96,4%) total thyroidectomy; 18% (20 patients) were submitted at the same time to lymph node dissection. Radioiodine therapy was performed in 60 patients (54%); 14 had more than one 131I therapy. Mean follow-up was 70 months (±23).

Mean tumor diameter was 7,4 mm (±3). 2,7% had aggressive histological variant; 35,1% were multifocal; 24,3% were bilateral; 19,8% had extrathyroidal extension; 8,1% had angioinvasion; 20,7% and 2,7% had lymph node and lung metastases, respectively. At the last observation, the majority (88,3%) was considered in complete remission; 5(4,5%) and 8(7,2%) patients had biochemical or structural evidence of disease, respectively. Only one patient died from disease (T1N1bM1).

Comparative analysis of patients with evidence of disease (Group I) vs patients in remission (Group II), showed in the former group higher mean tumor diameter (8,7 vs 7,3mm, p=0,074) and predominance of older patients (mean age at diagnosis: 48,1±14,6 vs 40,3±19,1, p=0,08) and male gender (38,5 vs 15,3%, p=0,041). Patients in Group I have shown more often: multifocality (53,9 vs 32,7%, p=0,133); bilateral disease (46,2 vs 21,4%, p=0,051); extrathyroidal extension (61,5 vs 14,3%, p=0,000); angioinvasion (38,5 vs 4,1%, p=0,000); positive surgical margins (23,1 vs 6,1%, p=0,035); lymph node disease (69,2 vs 14,3%, p=0,000) and lung metastization (23,1% vs none, p=0,000).

Conclusion: In general, PTMC patients have good prognosis. In the present series, patients with worse prognosis present more often extrathyroidal extension, angioinvasion, incomplete resection, multifocality, lymph node disease, lung metastases, and involve more frequently older-aged patients and male gender. Therefore, these markers might be clinical relevant for staging, treatment decisions and follow-up.

Nothing to Disclose: PM, DM, JSP, MDSV, RS, VL, MJB

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