Trends in Thyroid Cancer Incidence in the Gulf Cooperation Council States: a 15-Year Analysis.

INTRODUCTION

Thyroid cancer is a predominant malignancy in the Gulf Cooperation Council (GCC) states. Explicit regional assessments of incidence are crucial among countries that share similar demographic, cultural, and economic characteristics. This study provides an assessment of trends in thyroid cancer in the GCC over fifteen years.

METHODS

Data included cases in the GCC, reported to the Gulf Center for Cancer Registration during 1998-2012 (N=10,417). Age-specific rates, age-standardized rates (ASR), and stage at diagnosis are compared between the GCC states during 1998-2002, 2003-2007, and 2008-2012. Standardization of rates was performed using the World Standard Population.

RESULTS

Between 1998-2002 and 2008-2012, the frequency of thyroid cancer in the GCC was approximately fourfold higher in females than males. The average ASR increased from 1.8 to 2.4/100,000 for males and 5.7 to 8.4/100,000 for females. Age-specific incidence showed a shift towards a younger age for women and an older age for males. During 1998-2012, the proportion of localized stage at diagnosis ranged from 18% in Oman to 57% in the UAE. The proportion of unknown stage varied considerably among states, ranging from 13% to 64%. Over the study period, the proportion of unknown stage increased in all but two states (Bahrain and Saudi Arabia).

CONCLUSION

The incidence of thyroid cancer in the GCC has generally increased. This could reflect improved testing, leading to enhanced detection and diagnosis of thyroid cancers, as well as a possible increase in exposure to risk factors. Improved ascertainment of stage data is essential to reflect changes in early diagnosis activities.