Institute of Radiation Protection and Dosimetry, Brazilian Nuclear Energy Commission, Rio de Janeiro, Brazil.
Thyroid. 2013 Jun;23(6):748-57. doi: 10.1089/thy.2012.0532. Epub 2013 May 28.
Thyroid cancer incidence has risen steadily over the last few decades in most of the developed world, but information on incidence trends in developing countries is limited. Sao Paulo, Brazil, has one of the highest rates of thyroid cancer worldwide, higher than in the United States. We examined thyroid cancer incidence patterns using data from the Sao Paulo Cancer Registry (SPCR) in Brazil and the National Cancer Institute's Surveillance Epidemiology End Results (SEER) program in the United States.
Data on thyroid cancer cases diagnosed during 1997-2008 were obtained from SPCR (n=15,892) and SEER (n=42,717). Age-adjusted and age-specific rates were calculated by sex and histology and temporal patterns were compared between the two populations.
Overall incidence rates increased over time in both populations and were higher in Sao Paulo than in the United States among females (SPCR/SEER incidence rate ratio [IRR]=1.65) and males (IRR=1.23). Papillary was the most common histology in both populations, followed by follicular and medullary carcinomas. Incidence rates by histology were consistently higher in Sao Paulo than in the United States, with the greatest differences for follicular (IRR=2.44) and medullary (IRR=3.29) carcinomas among females. The overall female/male IRR was higher in Sao Paulo (IRR=4.17) than in SEER (IRR=3.10) and did not change over time. Papillary rates rose over time more rapidly in Sao Paulo (annual percentage change=10.3% among females and 9.6% among males) than in the United States (6.9% and 5.7%, respectively). Regardless of sex, rates rose faster among younger people (<50 years) in Sao Paulo, but among older people (≥50 years) in the United States. The papillary to follicular carcinoma ratio rose from <3 to >8 among both Sao Paulo males and females, in contrast to increases from 9 to 12 and from 6 to 7 among U.S.males and females, respectively.
Increased diagnostic activity may be contributing to the notable rise in incidence, mainly for papillary type, in both populations, but it is not likely to be the only reason. Differences in iodine nutrition status between Sao Paulo and the U.S. SEER population might have affected the observed incidence patterns.
在过去几十年中，大多数发达国家的甲状腺癌发病率稳步上升，但发展中国家发病率趋势的信息有限。巴西圣保罗拥有全球最高的甲状腺癌发病率之一，高于美国。我们使用巴西圣保罗癌症登记处（SPCR）和美国国家癌症研究所的监测、流行病学和最终结果（SEER）计划的数据，研究了甲状腺癌的发病模式。
我们从 SPCR（n=15892）和 SEER（n=42717）获得了 1997-2008 年期间诊断出的甲状腺癌病例的数据。按性别和组织学计算了年龄调整和特定年龄的发病率，并比较了这两个人群之间的时间模式。
两个人群的总体发病率随时间推移而增加，女性（SPCR/SEER 发病率比[IRR]=1.65）和男性（IRR=1.23）的发病率均高于美国。在两个人群中，乳头状癌都是最常见的组织学类型，其次是滤泡状和髓样癌。组织学的发病率在圣保罗一直高于美国，滤泡状癌（IRR=2.44）和髓样癌（IRR=3.29）的差异最大。女性的整体女性/男性 IRR 高于 SEER（IRR=4.17）（IRR=3.10），且随时间变化而不变。乳头状癌的发病率在圣保罗随时间的变化更快（女性每年增长 10.3%，男性每年增长 9.6%），而在美国则分别为每年增长 6.9%和 5.7%。无论性别如何，在圣保罗，发病率在较年轻人（<50 岁）中上升较快，但在美国，在较老年人（≥50 岁）中上升较快。在圣保罗的男性和女性中，乳头状癌与滤泡状癌的比例从<3 上升到>8，而在美国的男性和女性中，该比例分别从 9 上升到 12，从 6 上升到 7。
诊断活动的增加可能是两个人群中发病率显著上升的主要原因，特别是对于乳头状癌，但这可能不是唯一原因。圣保罗和美国 SEER 人群之间的碘营养状况差异可能影响了观察到的发病模式。
