Introduction: Thyroid cancer is the most common among all endocrine malignancies. The worldwide prevalence of goitre in the general population is estimated at 4-7 percent and the incidence of malignancy in goitrous thyroid is about ten percent. It is postulated that goitrous thyroid is a precursor lesion to the development of malignant thyroid diseases. As Sarawak is a state well known for endemic goitre, this study focused on establishing the incidence of thyroid malignancy among goitrous thyroid swellings.
Methods: This study was a hospital-based retrospective study on the archived collection of the surgically-removed thyroid specimens from the Sarawak General Hospital, Malaysia. Cases were grouped into cancer and non-cancer groups. The cancer group included papillary thyroid carcinoma (PTC), PTC follicular variant, follicular carcinoma and anaplastic carcinoma (ANA).
Results: A total of 820 thyroid cases which underwent surgical removal in years 2000 to 2004 were collected. Of these, 143 (17.4 percent) were male and 677 (82.6 percent) female. It was observed that the highest prevalence of thyroid swelling cases occurred in the age group 41-60 years while the lowest prevalence occurred in the age group under 21 years, 371 (45.2 percent) vs. 31 (3.8 percent). By ethnicity, the Ibans and Malays were found to have a higher prevalence at 275 (33.5 percent) and 196 (23.9 percent), respectively, while the lowest prevalence was observed in Indians, 11 (1.3 percent). 55 cases (6.7 percent) were found to be cancerous and the rest (93.3 percent) were non-cancerous thyroid swellings. Histologically, the highest incidence of carcinoma was PTC (4.0 percent) and the lowest was ANA (0.2 percent).
Conclusion: Based on our observations, although goitrous thyroid swelling is quite a common problem in Sarawak, thyroid malignancy is not a major issue. Among thyroid malignancies, PTC is the most common histological type of malignancy.