Thyroid cancers in Singapore 1968-'77.

Thyroid cancers from the Cancer Registry of Singapore over a ten . year period were analysed in two separate periods 1968-'72 and 1973-'77. Biopsy materials were reviewed and classified according to the WHO Classification of thyroid cancers. The crude incidence rates per 100.000 population per year was 1 in males and 3 in females. No definite ethnic group differences were observed. Papillary carcinoma was by far the commonest cancer followed by follicular carcinoma. Comparison between the two periods of study revealed a slight tendency to decline in incidence among the females. The papillary-follicular carcinoma ratio showed a progressive increase with time. The incidence of undifferentiated carcinoma had also declined over the same period. This may reflect changes in the environment which have an influence on the incidence and histological types of thyroid cancers in Singapore.