Increasing Incidence of Thyroid Cancer in Puerto Rico, 1985-2004

Abstract

Objective: Thyroid cancer has become one of the fastest growing malignancies in several countries worldwide. Few studies have examined thyroid cancer trends in Puerto Rico, and those studies have been conducted over relatively short time frames. This study aimed to describe both overall thyroid cancer incidence trends by age, sex, and histology, and the mortality rate by age and sex in Puerto Rico for the period of 1985 to 2004. Methods: Using the Central Cancer Registry of Puerto Rico database, we conducted a retrospective study of patients with thyroid cancer diagnosed from January 1, 1985, to December 31, 2004. Results: The overall incidence rate of thyroid cancer increased from 3.0 to 7.0 per 100,000 population (a 2.3-fold increase), with an annual percent change (APC) of 5.3% (p<0.05) during the period of 1985 to 2004. Incidence rates were higher for females (rising from 4.7 in 1985 to 10.5 per 100,000 women in 2004) compared to those for males (rising from 1.1 in 1985 to 3.0 per 100,000 men in 2004). The rising trend was mostly due to an increase in the incidence of papillary thyroid cancer, which rose from 2.4 to 6.0 per 100,000 population (a 2.5-fold increase), with an APC of 5.7% (p<0.05). The overall mortality rate of thyroid cancer was very low (0.4 in 1985 and 0.3 per 100,000 population in 2004), with a non-significant APC of -1.1% (p>0.05). Conclusion: The incidence of thyroid cancer in Puerto Rico increased significantly from 1985 to 2004, mostly due to an increase of papillary cancer. However, the mortality remained low.