Differentiated thyroid carcinoma: comparison between papillary and follicular carcinoma in a single institute

To compare and contrast the clinical presentation and treatment outcome of patients with papillary and follicular thyroid carcinoma and to study the pattern of practice of treatment of differentiated thyroid carcinoma in Hong Kong.

The clinical presentation and treatment outcomes were reviewed for 1057 patients with differentiated thyroid cancers who were treated at the Queen Elizabeth Hospital, Hong Kong, from 1960 to 1997. Eight hundred forty-two patients had papillary thyroid carcinomas (PTC), and 215 had follicular thyroid carcinomas (FTC). The mean follow-up was 9.2 years.

The differences in the clinical factors of PTC to FTC were as follows: PTC had a higher incidence (3.9:1); these patients were younger at presentation (median age, 44 vs 49), showed a higher female-male ratio (4.5 vs 2.9) and smaller primary tumor size (median 2 cm vs 3.5 cm), and a higher incidence of multifocal disease (28.3% vs 18.1%), extrathyroidal extension (39.4% vs 14%), and more lymph node metastases (33.3% vs 12.1%). The incidence of distant metastases was higher for patients with FTC (28.8% vs 8.9%), and cause-specific survival rates were lower (p =.001). The locoregional control rates were not significantly different (p =.2). The 10-year cause-specific survival, freedom from distant metastasis, and locoregional failure figures for PTC compared with FTC were 92.1% vs 81%, 90.8% vs 72.3%, and 78.5% vs 83%.

Although patients with PTC tend to have more advanced locoregional disease compared with those with FTC, the likelihood of locoregional control is similar, and the probability of cure is better.