Comparison of clinical characteristics at diagnosis and during follow-up in 118 patients with Hurthle cell or follicular thyroid cancer

Background Hurthle cell cancer (HCC) is considered by some to be a variant of follicular cancer (FC), but many think it is a distinct histologic tumor with a more aggressive behavior. Methods The influence of age at diagnosis, tumor stage, gender, and extent of operation on disease-free interval and cause-specific mortality at 5 and 10 years after initial thyroidectomy was analyzed. Results The 10-year disease-free interval was 75% for FC and 40.5% for HCC (P = .08). The 10-year cause-specific mortality was 20% for FC patients and 51% for HCC (P = .2). The risk factors for HCC progression and survival were extrathyroidal invasion, presence of metastases at diagnosis, male gender, and extent of thyroidectomy, whereas for FC, the only significant risk factors were extrathyroidal invasion and presence of metastases at diagnosis. Conclusion Patients with HCC have more aggressive tumors than patients with FC. Our data suggest that FC and HCC should be classified as distinct tumors.