Descriptive epidemiology of thyroid cancer in greater Bombay.

In this paper an attempt has been made to present a descriptive epidemiology of thyroid cancer in Bombay, and it is discussed in relation to age, demographic and socio economic composition of the population, using the most recent five year date. Time trend analysis of this cancer by sex has also been discussed using the last 30 years data. When international incidence of thyroid cancer was ranked in descending order for various countries, the incidence recorded for Bombay was found to be at the lowest level in both the sexes. Thyroid cancer is about three times more frequent among women than men, but this relative excess varies with the histologic type and age. As in the case of the majority of cancers, the incidence curve for thyroid cancer rises with age. However in men, the increase continues consistently with advancing age, while in women it begins to level off after the age 30, leading to an almost equal sex ratio in old age. In Bombay the incidence of thyroid cancer in men was found to be the highest in Muslims and in Christian women. No association was observed between thyroid cancer and education level attained by these patients. The four main histologic types of thyroid cancers i.e. papillary, follicular, anaplastic and medullary are also observed in Bombay. It has been noted that there is an increasing trend in the age-adjusted incidence rate for thyroid cancer in both the sexes in Bombay in the period under review 1964 to 1993. But the increase in incidence was found to be statistically significant only in males.