title: [Malignant transformation of thyroid cancer; poorly differentiated cancer and anaplastic cancer transformation].
abstract: The prognosis of thyroid cancer depends largely on histological differentiation and clinical stage. The prognosis in anaplastic cancer is worst, in well differentiated cancer it is best; poorly differentiated cancer takes a middle position. The prognosis of patients with differentiated cancer is generally good, however, there are cases with malignant transformation such as poorly differentiated, anaplastic and squamous-cell cancer transformation. We studied the frequency and the inducement factors of malignant transformation in patients with thyroid cancer. The frequency of poorly differentiated, anaplastic and squamous-cell cancer transformation was 13.6%, 6.4% and 0.7%, respectively. In anaplastic cancer transformation, irradiation is an important factor.
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002277:Carcinoma / Q000453:epidemiology / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000473:pathology; D002471:Cell Transformation, Neoplastic / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012737:Sex Factors; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000473:pathology*