OBJECTIVETo investigate the clinical features and treatment of multifocal papillary thyroid carcinoma (PTC).

METHODSA retrospective survey was carried out in 648 patients with PTC who underwent surgery from January 1997 to December 2006. One hundred and sixty-eight cases of the patients presented with multiple tumor masses (> or = 2). The risk factors, including sex of the patients, age at diagnosis, family history of thyroid tumor, multiplicity and bilaterality of tumor, extra-thyroidal extension, lymph node involvement and other were analyzed between solitary PTC and multifocal PTC group.

RESULTSThe mean age of the patients was 42 years (range, 14 - 78 years), included 49 male and 119 female. Tumor foci were found in both thyroid lobes in 117 cases (69.6%). Patients with multifocal PTC were characterized by a higher ratio of male (P = 0.004), family history of thyroid tumor (P = 0.031), neck lymph node metastasis (P = 0.008) and extra-thyroidal extension (P = 0.001). However, solitary PTC tended to be with a higher rate of benign goiters in pathologic examination. In multifocal PTC group, male, neck lymphadenectasis, > or = 3 tumor masses or bilaterality of tumor tended to presented with larger tumor, more neck lymph node metastasis and extra-thyroidal extension; And a less malignant tumor in the cases detected with benign goiters in histological examination. By the end of 2007, 164 cases (97.6%) completed follow-up with a mean period of 46.1 months (range, 2 - 127 months), 5 died in the meantime. One patient has been followed-up for 16 months for suspect of lung metastases by chest X-ray. Recurrence occurred in 8 patients and were re-resected, 2 in remnant thyroid and 6 in neck lymph nodes. The overall 1-, 2-, 5-, and 10-year survival rate was 98.2%, 97.4%, 96.5% and 96.5%, respectively. American Joint Committee on Cancer (AJCC) stage was associated with prognosis significantly (chi(2) = 168.832, P = 0.000).

CONCLUSIONSMultifocus is one of the clinical features of PTC and is more malignant than solitary PTC. Total thyroidectomy with central compartment neck dissection could be standard treatment. Lateral nodal dissection is not necessary except for the cases with lymph node metastasis. AJCC stage is still the best prognostic factor.