Increased Incidence of Thyroid Cancer in Singapore Is Not Solely Due to Papillary Microcarcinoma

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Clinical/Translational
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 288
Jesse SL Hu*1, Aizhen Jin2, Wee Boon Tan3, Khuan Kew Chow2, Kee Yuan Ngiam3 and Rajeev Parameswaran3
1Jurong Health Services, Singapore, Singapore, 2Health Promotion Board, Singapore, 3National University Hospital, Singapore
Background / Aims

The annual incidence of thyroid cancer is known to vary with geographic area, age and gender. In recent years, there have been reports of increasing incidence of thyroid cancer worldwide, which has been attributed to increase in detection of micropapillary subtype. We sort to investigate if this holds true in Singapore.

Methods

This is a retrospective analysis of thyroid cancers treated in Singapore between the years 1974 and 2013. The data was obtained from the National Cancer Registry and included patients treated in all public hospitals in Singapore. Demographic data on gender, age, ethnicity, tumour subtype and mortality is available for the said period while additional data on tumour size and treatment is only available from 2007 onwards. For all included cases, the overall incidence and mortality of thyroid cancer for each year from 1974-2013 were calculated. All rates were age-adjusted to the world standard population.

Results

 

The age-standardized incidence rate of thyroid cancer increased by 224% (2.5 per 100,000 in 1974 to 5.6 per 100,000 in 2013, p<0.05). The median age at diagnosis was 64.5 for males & 46 for females in 1974 compared to 52 and 51 respectively, in 2013. Thyroid cancer affected women more than men by a ratio of 3 to 1. The increased incidence was predominantly seen in the Malays by 290% (2.1 per 100,000 in 1974 to 6.0 per 100,000 in 2013, p<0.05) as compared to the Chinese and Indians.

The distribution of histological categories was as follows: 81.1% papillary, 12.1% follicular and 6.8% others (medullary & anaplastic). The increase in incidence of papillary subtype is mainly due to the increase in diagnosis of smaller cancers (less than 5cm). However, the percentage of patients diagnosed with micropapillary carcinoma remained the same (36.3% in 2007 vs 38.6% in 2013, p = 0.21). Although incidence of thyroid cancer has increased since 1974, the mortality rate has remained stable.

Conclusions

The trend of increasing incidence of thyroid cancer seen in Singapore is similar to other parts of the world, but it is not attributed to increase in diagnosis of micropapillary subtype.

Nothing to Disclose: JSH, AJ, WBT, KKC, KYN, RP

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