Changes of Clinicopathological Characteristics and Prognosis of Papillary Thyroid Cancer in Korea

Thyroid cancer is the most frequent endocrine tumor and increased across the world, especially in micropapillary thyroid cancer under 1 centimeter. Increased incidence of thyroid cancer was attributed to early diagnosis by health screening with neck ultrasonography and fine needle aspiration cytology. However, several studies suggested the possibility of true increment in thyroid cancer, based on the fact that large size tumor also increased, as well small size tumor. The Annual Report of the Korea Central Cancer Registry reported that the incidence of thyroid cancer was increased rapidly with higher rate than other countries and similar rate as incidence in the area exposed to radiation, although studies about high incidence rate and clinicpathological characteristics of Korea were not yet performed. Present study was conducted using medical records of thyroid cancer patients who visited Seoul National University Hospital Thyroid Clinic from 1962 to 2009, to analyze changes of cliniopathologic characteristics and prognosis and risk factors. The mean age of subjects was 46.5±12.6 years of age and female was 84%, with median follow up duration of 5.1 years (1~48). During follow up duration, recurrence and mortality rate were 13.3% and 1.4%, respectively. The number of patients in our study increased rapidly from 278 before 1990 to 2030 after 2000, with rates of papillary thyroid cancer from 88% before 1990 to 92% after 2000. The age of diagnosis was increased from 38.9±12.8 before 1990 to 44.3±13.2 during 90~99 to 48.4±11.8 after 2000. The proportion of male gender was increased from 13.3% before 1990 to 13.7% during 90~99 to 16.9% after 2000. The increment of proportions of micropapillary thyroid cancer was prominent from 11.3% before 1990 to 18.0% during 90~99 to 49.6% after 2000, suggesting that the increment of thyroid cancer was attributed to early diagnosis by health screening. In changes of pathological characteristics, rates of patients with lymph node involvement was reduced from 78.7% before 1990 to 59.3% during 90-99 to 46.1% after 2000, and those with extrathyroidal extension was also reduced from 65.7% before 1990 to 68.5% during 90-99 to 57.4% after 2000. Although these reductions resulted from increasing diagnosis by health screening, the degrees of reduction were less than the degree of increment of small size tumor. Furthermore, our results of rates in lymph node involvement and extrathyroidal extension were still higher those of other countries, and the rates of distant metastasis were not decreased, suggesting that the increment of thyroid cancer resulted from not only early diagnosis but also true increasing development of thyroid cancer. Regarding changes of prognosis according to three time periods (before 1990, during 90-99, after 2000), 5-year recurrence and mortality rate were reduced from 11.0% to 7.0% to 5.9% and from 1.5% to 1.1% to 0.2%, respectively.10-year recurrence and mortality rate were also reduced from 20.1% to 15.2% and from 4.8% to 2.5%, respectively. Risk factors for recurrence were male gender (Odds ratio [OR], 1.579; 95% confidence interval [CI], 1.001-2.489; p=0.050), large size tumor (OR, 1.804; 95% CI, 1.564-2.081; p<0.001), regional lymph node involvement (OR, 3.660; 95% CI, 2.177-6.153; p<0.001), and extrathyroidal extension (OR, 2.142; 95% CI, 1.161-3.953; p=0.002). Risk factors for mortality were old age over 55 years (OR, 12.399; 95% CI, 3.191-45.339; p<0.001), male gender (OR, 4.372; 95% CI, 1.511-12.650; p=0.007), regional lymph node involvement (OR, 10.769; 95% CI, 1.349-85.975; p=0.025). In summary, thyroid cancer is rapidly increasing in Korea, especially in micropapillary thyroid cancer. The rates of pathological features relating poor prognosis were also decreased and the prognosis was improved. However, thyroid cancer in Korea showed more aggressive features in pathological characteristics and higher rates of recurrence and mortality, suggesting that thyroid cancer in Korea has different characteristics from other countries, warranting further studies.

Author dc:creator

• 최, 훈성

Contributors dc:contributor

• 조, 남한
• 보건대학원
• 201027229

• 갑상선암

Language dc:language

en

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000012459
000000012459

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/7508