A STUDY OF 875 CASES OF THYROID-CANCER OBSERVED OVER A 15-YEAR PERIOD(1975-1989) AT THE KING-FAISAL-SPECIALIST-HOSPITAL AND RESEARCH-CENTER

Thyroid cancer (TC) is a common malignancy encountered at King Faisal Specialist Hospital and Research Centre (KFSH&RC). Of 19,585 different malignant tumors seen during the period from 1975 to 1989, there were 875 cases (4.4%) of TC. Of 1374 tumors of endocrine glands seen durin g the same period, 67% were thyroid neoplasms. TC represented 7.5% (61 8 cases) of all neoplasms in the females, second only to breast cancer . All types of TC were seen, with papillary thyroid carcinoma (PC) bei ng the most common (79%). Anaplastic, medullary, follicular (FC), mali gnant lymphoma and Hurthle cell cancer accounted for 5.4%, 5.3%, 4.3%, 3.6% and 0.9% respectively. The frequency of PC was very similar (16% ) in each of the third, fourth and fifth decades. The relative frequen cy (RF) of different types of TC was highest for PC with a ratio of 18 :1 between PC and FC, which could be the highest ever reported. There was a clearly progressive increase in the number of thyroid tumors ref erred between 1975 and 1989. Although this increase was evident for bo th sexes, it was more apparent for females. There was also a distinct increase (P < 0.01) in the RF of PC from 76% (1975 to 1980) to 85% (19 86 to 1989) with a decrease in FC from 9% to 2.5% over the same time p eriods.