Classification of papillary cancer of the thyroid based on prognosis

Between 1965 and 1988 there were 2953 patients with papillary carcinoma treated at Noguchi Thyroid Clinic. Among them 761 patients were excluded because the primary tumor was < 10 mm in maximum diameter, the patient's age was > 80, or the patient underwent noncurative surgery. The remaining 2192 patients, 192 men and 2000 women, were analyzed. The mean follow-up period was 12.5 years. Total thyroidectomy, subtotal thyroidectomy, lobectomy with or without isthmectomy, and less than lobectomy were performed in 2.3%, 40.3%, 44.2%, and 13.2%, respectively. Modified radical neck dissection, partial node excision, and no node excision were performed in 77.8%, 6.4%, and 15.8%, respectively. Men and women were separately analyzed because their risk factors and prognosis were significantly different. Multivariate analysis was carried out according to Cox's regression hazard model. Independently significant factors affecting prognosis in men were aged and gross nodal metastasis; and age, gross nodal metastasis, tumor size, and number of adhered tissues or organs were the factors in women. Based on those risk factors patients were classified into three groups. For men, 65.6% were classified in the excellent group and their 10-year survival was 98.4%; 17.2% were classified as intermediate and 17.2% as poor with survival rates of 90.1% and 74.4%, respectively. For female patients 69.6% were classified in the excellent group, 18.6% in the intermediate group, and 11.9% in the poor group with 10-year survivals of 99.3%, 96.4%, and 88.8%, respectively.