Is the Incidence of Thyroid Cancer Increasing in Saudi Arabia?

Abstract

The inception of KFSH&RC was in 1975. Since then, the hospital has grown in its bed capacity and reputation, and there have been marked improvements in health care and public medical awareness as well as population growth in Saudi Arabia. As expected, this resulted in an increase in the referral rate to KFSH&RC of cases that need tertiary care, including cancer. According to the annual report of the tumor registry at KFSH&RC, 3 there were 4077, 7052 and 7435 cancer patients in the period of 1975-1980, 1981-1985, and 1986-1989, respectively (the periods studied by Ahmed et al.). The marked increase in the number of cancer patients seen at KFSH&RC was true for all 35 types of cancer examined. It would be very unlikely that all types of cancer are increasing in Saudi Arabia at this rate.It is interesting that the rate of referral of thyroid cancer to KFSH&RC has increased in these three periods, even when expressed as a percentage of total cases of cancer referred (2.99%, 4.33% and 5.77%, respectively). However, this was also true for other cancers such as those of the cervix, ovary and central nervous system. In the case of thyroid cancer, the increase can be explained by the fact that thyroid remnant ablation with radioiodine has been increasingly used in the routine management of papillary thyroid cancer. KFSH&RC is one of the few centers that has the facility for high dose radioiodine therapy and it is the national referral center for thyroid cancer in Saudi Arabia.Increased referral rate, due to the reasons mentioned above, rather than an increased incidence of thyroid cancer may also explain: 1) the observation that the estimated incidence of thyroid cancer in Saudi Arabia is still lower than that in the United States; 1 2) the observed increase in the female to male ratio over the three periods of the study by Ahmed et al.;2 health care delivery would be expected to improve later in females than in males; and 3) the observed increase in the relative frequency of papillary thyroid cancer; incidental papillary (but not follicular) thyroid cancer is not uncommonly discovered in specimens of thyroidectomy done for other indications, such as multinodular goiter, and is increasingly managed more aggressively.We think that there is no convincing evidence that the incidence of thyroid cancer is increasing in Saudi Arabia.