Clinical characteristics of poorly differentiated thyroid carcinomas compared with those of classical papillary thyroid carcinomas.

OBJECTIVE

The aim of this study was to compare the clinical presentation and prognosis of poorly differentiated thyroid carcinoma (PDTC) with those of classical papillary thyroid carcinoma (PTC) to identify the appropriate surgical modalities for use in conjunction with radioactive iodide ((131)I) therapy and external radiotherapy for treating PDTC.

DESIGN

Sixty-seven PDTC patients (mean age 50.3 +/- 18.1 years, range 14-82 years) underwent surgery at the Chang Gung Medical Centre (CGMC), Linkou. To compare clinical presentations and treatment outcomes, 134 age- and gender-matched patients with classical PTC were selected randomly from the patient database at CGMC.

RESULTS

Of the 67 PDTC patients, 53 underwent near-total thyroidectomy. Following surgery, 45 were administered (131)I for remnant ablation and treatment of distant metastatic disease. Forty-one of the 67 (61.2%) patients with PDTC and 26/134 (19.4%) with classical PTC failed to achieve disease-free status. Twenty-four of the 67 (34.3%) PDTC patients eventually died of thyroid cancer after a mean follow-up of 5.9 +/- 0.6 years. Age and TNM staging at surgery were significant indicators of PDTC patient survival and mortality.

CONCLUSIONS

As the prognosis for PDTC patients is poorer than that for classical PTC patients, (131)I treatment following surgery is useful. To improve the survival rate, early diagnosis is crucial for PDTC.