Thyroid cancer incidence in Asian migrants to the United States and their descendants

The environmental burden on endocrine neoplasia: a review on the documented impact of endocrine disrupting chemicals

INTRODUCTION

Endocrine-disrupting chemicals (EDCs) have gained more importance in the past decade, mostly due to their role in the pathogenesis of disease, especially in carcinogenesis. However, there is limited literature on the environmental burden on some of the less common endocrine neoplasia.

AREAS COVERED

This review focuses on both observational and experimental studies linking exposure to EDCs and endocrine neoplasia specifically pituitary, thyroid, adrenal and neuroendocrine tumors. Following PRISMA guidelines, a search of English peer-reviewed literature was performed using Medline and Google Scholar, giving preference to recent publications.

EXPERT OPINION

Exposure to EDC occurs not only in the household but also at work, whether it is in the office, factory, or farm and during transport from one location to another. Many studies have evaluated the effect of single environmental agents; however, humans are rarely exposed to only one EDC. Different EDCs and different levels of exposure may interact together to provide either a synergistic and/or an antagonistic disruption on human health, and hence a complex mechanism to elucidate. The ultimate adverse effect is difficult to predict, as it is not only influenced by the degree of exposure, but also by genetics, lifestyle, comorbidities, and other stressors.

Behaviour and epidemiology of differentiated thyroid cancer among filipinos in and outside the Philippines: Comparison between Qatar, Canada and Philippines

Background

No study assessed the behaviour/epidemiology of differentiated thyroid cancer (DTC) among Filipinos in the Middle East/north Africa; or compared such behaviour with Filipino DTC patients in and outside the Philippines.

Materials and methods

Retrospective review of all adult Filipinos with DTC diagnosed between 2015 and 2020 at our institution [papillary TC (PTC, n = 110); follicular TC (FTC, n = 4)]. Chi-square or t-test compared the frequency, demography, history, ultrasound, laboratory and histopathology of PTC vs FTC; and compared the epidemiology of DTC among Filipinos in Qatar vs Canada (1 study) vs the Philippines (3 studies).

Results

DTC frequency was ≈43.84 cases/100,000 Filipinos in Qatar. Males had more aggressive disease in terms of lymphovascular invasion, number of nodules, stage IV disease and metastases. PTC and FTC were similar, but more PTC patients presented with solid tumors and higher number of involved lymph nodes. DTC behaviour among Filipinos in Qatar vs Canada was fairly homogenous. Conversely, DTC among Filipinos in Qatar vs Philippines exhibited many dissimilarities: Qatar had significantly younger patients, less hyperthyroid/thyrotoxicity symptoms and neck swelling at presentation, fewer solid nodules, micro-calcifications, and multi-nodular disease; smaller tumors; more stage I and less stage IV disease; and no distant metastasis (P 0.01 to < 0.0001).

Conclusions

DTC epidemiology among Filipinos in Qatar and Canada was fairly homogenous. Conversely, DTC in Qatar vs the Philippines was dissimilar. DTC among Filipinos in Qatar has presentations that could be misinterpreted as non-suspicious. This warrants additional practices for earlier detection among Filipinos.

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Epidemiology of differentiated thyroid cancer among Filipinos living Qatar vs Canada has considerable similarities.

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Epidemiology of differentiated thyroid cancer among Filipinos living Qatar vs the Philippines appears to be heterogenous.

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Differentiated thyroid cancer among Filipinos living in Qatar has presentations that could erroneously be misinterpreted as non-malignant by unsuspecting health worker, and seemingly lower tumor load compared to those living in the Philippines.

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Thyroid lesions among Filipinos in Qatar should be taken seriously, warranting additional practices for earlier detection among Filipinos.

Thyroid Cancer Incidence Trends Among Filipinos in the United States

OBJECTIVE

To analyze thyroid cancer incidence trends among Filipinos relative to non-Filipino Asians and non-Hispanic Whites in the US.

STUDY DESIGN

Population-based analysis of cancer incidence data.

METHODS

Population-based analysis of cancer incidence data from Surveillance, Epidemiology, and End Results 9 detailed Asian/Pacific Islander subgroup incidence and population datasets. Adult patients aged 20 and older with thyroid cancer diagnosed in 2004 to 2014 were included. Annual percent change (APC) of the incidence rates were calculated using joinpoint regression analysis.

RESULTS

The incidence rates were 19.57 (95% CI 19.03-20.12) per 100,000 for Filipinos, 10.45 (95% CI 10.22-10.68) per 100,000 for non-Filipino Asians, and 13.94 (95% CI 13.85-14.02) per 100,000 for non-Hispanic Whites. The highest increase was seen among non-Hispanic Whites (average APC 5.04, 95% CI 4.61-5.46). Incidence rates of tumors ≤ 2 cm remained stable among Filipinos but increased in non-Filipino Asians (average APC 5.38, 95% CI 2.51-8.34) and non-Hispanic Whites (average APC 5.81 95% CI 4.52-7.11).

CONCLUSION

Filipinos have high incidence of thyroid cancer compared with other racial/ethnic groups. However, non-Hispanic Whites have the highest increase in incidence rates, resulting in a significant narrowing of the gap in incidence rates between Filipinos and non-Hispanic Whites. This is most likely due to enhanced detection of small tumors in non-Hispanic Whites. Laryngoscope, 2021.

Thyroid cancer incidence disparities among ethnic Asian American populations, 1990-2014

PURPOSE

Asian/Pacific Islanders (APIs) are at high risk of thyroid cancer, hence we examined thyroid cancer's incidence among disaggregated API subgroups in the United States (U.S.) to identify potential ethnic-specific disparities.

METHODS

Data from 1990 to 2014 in the Surveillance, Epidemiology, and End Results Program (SEER) were used to compare age-adjusted incidence rates (AAIRs) of thyroid cancer for seven API ethnic subgroups to non-Hispanic whites (NHWs) using incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Sex, age, tumor histotype, and year of diagnosis were considered. Trends were evaluated using average annual percent change (AAPC) statistics.

RESULTS

The highest AAIRs (per 100,000 person-years) were among Filipinos (female AAIR=20.49, male AAIR=7.06) and the lowest among Japanese (female AAIR=8.36, male AAIR=3.20). However, Filipinos showed significantly lower incidence of medullary tumors when compared to NHWs (female IRR=0.60, 95% CI 0.40-0.87, male IRR=0.26, 95% CI 0.26-0.51). The largest increasing trends were among Asian Indian/Pakistanis for females (AAPC=5.19, 95% CI 3.81 to 6.58) and Koreans for males (AAPC=4.57, 95% CI 3.14 to 6.03).

CONCLUSIONS

There are clear differences in thyroid cancer incidence and trends when U.S. API ethnic subgroups are examined separately. Disaggregating APIs in research can provide critical information for understanding thyroid cancer risk.

Differential Expression of Non-Coding RNA Signatures in Thyroid Cancer between Two Ethnic Groups

Filipino Americans show higher thyroid cancer recurrence rates compared to European Americans. Although they are likely to die of this malignancy, the molecular mechanism has not yet been determined. Recent studies demonstrated that small non-coding RNAs could be utilized to assess thyroid cancer prognosis in tumor models. The goal of this study is to determine whether microRNA (miRNA) signatures are differentially expressed in thyroid cancer in two different ethnic groups. We also determined whether these miRNA signatures are related to cancer staging. This is a retrospective study of archival samples from patients with thyroid cancer (both sexes) in the pathology division from the last ten years at Loma Linda University School of Medicine, California. Deidentified patient demographics were extracted from the patient chart. Discarded formalin-fixed paraffin-embedded tissues were collected post-surgeries. We determined the differential expressions of microRNA in archival samples from Filipino Americans compared to European Americans using the state-of-the-art technique, HiSeq4000. By ingenuity pathway analysis, we determined miRNA targets and the pathways that those targets are involved in. We validated their expressions by real-time quantitative PCR and correlated them with the clinicopathological status in a larger cohort of miRNA samples from both ethnicities. We identified the differentially upregulated/downregulated miRNA clusters in Filipino Americans compared to European Americans. Some of these miRNA clusters are known to target genes that are linked to cancer invasion and metastasis. In univariate analysis, ethnicity and tumor staging were significant factors predicting miR-4633-5p upregulation. When including these factors in a multivariate logistic regression model, ethnicity and tumor staging remained significant independent predictors of miRNA upregulation, whereas the interaction of ethnicity and tumor staging was not significant. In contrast, ethnicity remained an independent predictor of significantly downregulated miR-491-5p and let-7 family. We provide evidence that Filipino Americans showed differentially expressed tumor-tissue-derived microRNA clusters. The functional implications of these miRNAs are under investigation.

BRAFV600E, hypothyroidism, and human relaxin in thyroid carcinogenesis

PURPOSE

BRAF^V600E, a major driver of thyroid cancer, evaluated in the context of thyroid hormones and human relaxin.

METHODS

Immunohistochemical expressions of BRAF^V600E, TSH, TSH receptor (TSHR), T4, T3 receptor (T3R), RLNH2, and its receptor, RXFP1, were evaluated in thyroid tumors from a retrospective U.S. population of 481 cancer cases diagnosed in 1983-2004.

RESULTS

BRAF^V600E was expressed in 52% of all thyroid tumors; expression of other markers ranged from 25% for T4 to 98% for RLNH2. Tumors predominantly exhibited hypothyroid-like conditions characterized by elevated TSH and TSHR and reduced T4. BRAF^V600E prevalence was significantly higher in tumors expressing TSH, TSHR, T3R, and RXFP1 and lower in tumors expressing T4. The proportion of BRAF^V600E mutation in classic papillary tumors significantly increased from 56 to 72% over the 21-year period of diagnoses, while expression of RXFP1, TSH, TSHR, and T3R decreased in non-tumor. Racial/ethnic differences were observed in thyroid hormone marker expression. Non-tumor expression of TSH, TSHR, and T3R were each associated with shorter overall survival, but did not remain significant after adjustment for demographic and clinical factors.

CONCLUSIONS

Our study provides the first evidence of the potential interaction of BRAF^V600E mutation, relaxin, and thyroid hormones in thyroid carcinogenesis. Moreover, our results suggest that hypothyroidism, influenced by RLNH2 activity, may underlie the development of the majority of thyroid cancers and mediate the role of BRAF^V600E in thyroid carcinogenesis. BRAF^V600E mutation is increasing in papillary thyroid cancers and may be contributing to the rising incidence of this malignancy.

Clinical Characterization of Post-parathyroidectomy Patients with Primary Hyperparathyroidism and the Concordance of Preoperative Localization Imaging with Histopathology at a Tertiary Hospital in Manila, Philippines

Background

Philippine studies on primary hyperparathyroidism (PHPT) and preoperative localization are scarce, making improvements on detection and recognition particularly difficult.

Objective

Describe the clinical profile of post-parathyroidectomy PHPT patients at The Medical City (TMC) and assess localization rates and concordance of neck ultrasound (UTZ) and 99mTc-sestamibi scan (MIBI) with surgical histopathologic findings.

Methodology

Retrospective chart review of PHPT Filipino patients who underwent parathyroidectomy at The Medical City from January 2004 to August 2018. Clinical profile and presentations were described and compared with international data. Imaging results were compared with surgical histopathology findings and the level of agreement was determined.

Results

Thirty-five patients were analyzed with female predominance (63%) and an average age of 53 years. Our population had more overt manifestations including skeletal abnormalities (51%), renal calculi (49%) and musculoskeletal symptoms (43%) prior to surgery compared to western countries, where symptoms were noted in less than 20%. MIBI had higher rates of detection than UTZ (80% versus 58%) but had similar localization rates (96.4% versus 94%). When performed together, given a positive result from either test, a much higher yield (93.8%) was observed. The level of agreement between MIBI and surgery was 72.5% (κ=0.54) while UTZ and surgery was 54.1% (κ=0.38).

Conclusion

Our Filipino subjects had predominantly overt symptomatic hyperparathyroidism upon diagnosis prior to surgery as opposed to more asymptomatic surgical patients in western countries. Combining UTZ and MIBI is a more successful preoperative localization approach in our setting than performing either imaging alone, especially in patients with nodular goiter.

Thyroid cancer mortality is higher in Filipinos in the United States: An analysis using national mortality records from 2003 through 2012

BACKGROUND

Well-differentiated thyroid carcinoma has a favorable prognosis, but patients with multiple recurrences have drastically lower survival. Filipinos in the United States are known to have high rates of thyroid cancer incidence and disease recurrence. To the authors' knowledge, it is unknown whether Filipinos also have higher thyroid cancer mortality rates.

METHODS

The authors studied thyroid cancer mortality in Filipino, non-Filipino Asian (NFA), and non-Hispanic white (NHW) adults using US death records (2003-2012) and US Census data. Age-adjusted mortality rates and proportional mortality ratios (PMRs) were calculated. Sex, nativity status, age at death, and educational attainment also were examined.

RESULTS

The authors examined 19,940,952 deaths. The age-adjusted mortality rates due to thyroid cancer were highest in Filipinos (1.72 deaths per 100,000 population; 95% confidence interval [95% CI], 1.51-1.95) compared with NFAs (1.03 per 100,000 population; 95% CI, 0.95-1.12) and NHWs (1.17 per 100,000 population; 95% CI, 1.16-1.18). Compared with NHWs, higher proportionate mortality was observed in Filipino women (3-5 times higher) across all age groups, and among Filipino men, the PMR was 2 to 3 times higher in the subgroup aged >55 years. Filipinos who completed a higher educational level had a notably higher PMR (5.0) compared with their counterparts who had not (3.5).

CONCLUSIONS

Negative prognostic factors for thyroid cancer traditionally include age >45 years and male sex. The results of the current study demonstrate that Filipinos die of thyroid cancer at higher rates than NFA and NHW individuals of similar ages. Highly educated Filipinos and Filipino women may be especially at risk of poor thyroid cancer outcomes. Filipino ethnicity should be factored into clinical decision making in the management of patients with thyroid cancer. Cancer 2017;123:4860-7. © 2017 American Cancer Society.

Thyroid cancer incidence among Asian immigrants to Ontario, Canada: A population-based cohort study

BACKGROUND

The highest rates of thyroid cancer are observed in Pacific Island nations as well as Australia and Asian countries bordering the Pacific. The objective of this study was to determine the risk for thyroid cancer among immigrants to Canada from Southeast and East Asia compared with immigrants from other regions and nonimmigrants.

METHODS

This was a population-based, longitudinal cohort study using health care administrative data to examine all residents of Ontario without pre-existing thyroid cancer. Individuals were followed from January 1997 or 5 years after they became eligible for health care coverage in Ontario, whichever came later. Patients were followed until March 2015 for incident-differentiated thyroid cancer, and then for recurrence.

RESULTS

The study followed 14,659,733 individuals for a median of 17 years. Thyroid cancer incidence was 43.8 cases per 100,000 person-years among Southeast Asian immigrants, 28.6 cases per 100,000 person-years among East Asian immigrants, 21.5 cases per 100,000 person-years among other immigrants, and 14.5 cases per 100,000 person-years among nonimmigrants. Incidence was highest among immigrants from the Philippines (52.7 cases per 100,000 person-years), South Korea (33.5 cases per 100,000 person-years), and China (30.0 cases per 100,000 person-years). Adjusted hazard ratios for thyroid cancer compared with nonimmigrants were 2.66 (95% confidence interval, 2.48-2.84) for Southeast Asian immigrants, 1.87 (95% confidence interval, 1.75-2.00) for East Asian immigrants, and 1.51 (95% confidence interval, 1.45-1.57) for other immigrants. Immigrants were more likely to have papillary histology and stage I cancer. East Asian immigrants, but not Southeast Asian immigrants, had a lower risk of recurrence (hazard ratio, 0.73 [95% confidence interval, 0.57-0.94] and 1.01 [95% confidence interval, 0.81-1.26], respectively).

CONCLUSIONS

Immigrants from Southeast and East Asia had markedly higher thyroid cancer incidence than nonimmigrants. At particularly elevated risk were immigrants from the Philippines, South Korea, and China. Cancer 2017;123:3320-5. © 2017 American Cancer Society.

Contrast-enhanced sonography for the identification of benign and malignant thyroid nodules: Systematic review and meta-analysis

PURPOSE

The use of contrast-enhanced sonography (CEUS) has yielded promising results in the differentiation of thyroid nodules. We conducted this meta-analysis to assess its performance in identifying and distinguishing between benign and malignant thyroid nodules.

METHODS

PubMed, Medline, Embase, and the Cochrane Library were searched for studies published through the end of December 2013. Sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and area under the curve were calculated.

RESULTS

A total of 13 studies were included in this meta-analysis. For the diagnosis of malignant thyroid nodules worldwide, the overall mean rates of sensitivity and specificity of CEUS were 90% (95% confidence interval [CI], 88-93%) and 86% (95% CI, 83-89%), respectively. The summary diagnostic odds ratio was 52.83 (95% CI, 21.71-128.55), and the area under the curve for the summary receiver operating characteristic curve was 0.94 (95% CI, 0.90-0.98).

CONCLUSIONS

This meta-analysis indicates that CEUS may be a valuable supplemental method, with high rates of sensitivity and specificity, to use for identifying and distinguishing between benign and malignant thyroid nodules.

Incidence of differentiated thyroid cancer in Canada by City of residence

Background

Thyroid cancer incidence in Canada is increased in high socioeconomic groups, and in urban compared with rural areas. The objective of this study was to analyze patterns in thyroid cancer incidence across Canada, particularly with respect to the major urban areas across the country, to identify whether there are any discrepancies in thyroid cancer incidence between Canadian cities.

Methods

Cases were drawn from the Canadian Cancer Registry. Demographic and socioeconomic information were extracted from the Canadian Census of Population data. We linked cases to income quintiles (InQs) by patients’ postal codes, and categorized residence by census metropolitan area ((CMA), population >100,000). Within the Toronto CMA we further classified by census subdivision (CSD).

Results

There were a total of 33 CMAs across the country. After controlling for demographic and socio-economic factors, we found that the Toronto CMA had an IRR of thyroid cancer that was significantly higher than all other CMAs across the country. For 70 % of CMAs and CAs across Canada, the IRR for thyroid cancer was less than half of the IRR for thyroid cancer in the Toronto CMA.

As Toronto is one of the largest CMAs, we then subdivided the Toronto area into CSDs to examine how incidence of thyroid cancer varies within this large area. The Toronto City core was used as the reference category and all other areas were compared directly to it. In doing so, we found that a contiguous area of three CSDs North of Toronto had higher IRRs compared with the Toronto city core: Markham, Vaughan and Richmond Hill.

Conclusions

After controlling for demographic and socioeconomic factors, we found that the Toronto CMA has the highest incidence of thyroid cancer nationwide. Several explanations could account for this discrepancy including increased detection due to increased access to imaging, differences in ethnicity or environmental exposures.

Both HCV and HBV are major causes of liver cancer in Southeast Asians

The incidence of hepatocellular carcinoma (HCC) is higher in Asian Americans than in other ethnicities. While hepatitis B virus (HBV) is common, hepatitis C virus (HCV) is more prevalent in some subgroups. Our goal was to determine the etiology of liver disease associated with HCC in subgroups of Asian Americans. This was an analysis of 510 Asian HCC patients at a US medical center. Patients were identified using ICD9 diagnosis. Multivariate logistic regression was used to study predictors of HCV as the cause of HCC. Patients were Southeast Asian, Chinese, and Korean, with similar gender, age, and foreign-born status. Southeast Asians had a similar proportion of HBV- and HCV-related HCC, while Chinese and Korean patients had a higher proportion of HBV-related HCC. HCC was usually associated with HBV in Chinese and Korean patients, but both HCV and HBV were important associations in Southeast Asians.

Uncovering nativity disparities in cancer patterns: Multiple imputation strategy to handle missing nativity data in the Surveillance, Epidemiology, and End Results data file

BACKGROUND

Although birthplace data are routinely collected in the participating Surveillance, Epidemiology, and End Results (SEER) registries, such data are missing in a nonrandom manner for a large percentage of cases. This hinders analysis of nativity-related cancer disparities. In the current study, the authors evaluated multiple imputation of nativity status among Hispanic patients diagnosed with cervical, prostate, and colorectal cancer and demonstrated the effect of multiple imputation on apparent nativity disparities in survival.

METHODS

Multiple imputation by logistic regression was used to generate nativity values (US-born vs foreign-born) using a priori-defined variables. The accuracy of the method was evaluated among a subset of cases. Kaplan-Meier curves were used to illustrate the effect of imputation by comparing survival among US-born and foreign-born Hispanics, with and without imputation of nativity.

RESULTS

Birthplace was missing for 31%, 49%, and 39%, respectively, of cases of cervical, prostate, and colorectal cancer. The sensitivity of the imputation strategy for detecting foreign-born status was ≥90% and the specificity was ≥86%. The agreement between the true and imputed values was ≥0.80 and the misclassification error was ≤10%. Kaplan-Meier survival curves indicated different associations between nativity and survival when nativity was imputed versus when cases with missing birthplace were omitted from the analysis.

CONCLUSIONS

Multiple imputation using variables available in the SEER data file can be used to accurately detect foreign-born status. This simple strategy may help researchers to disaggregate analyses by nativity and uncover important nativity disparities in regard to cancer diagnosis, treatment, and survival.

Disparities in the initial presentation of differentiated thyroid cancer in a large public hospital and adjoining university teaching hospital

BACKGROUND

Healthcare disparities associated with insurance and socioeconomic status have been well characterized for several malignancies, such as lung cancer. To assess whether there are healthcare disparities in thyroid cancer, this study evaluated the stage on initial presentation of patients with differentiated thyroid cancer (DTC) in a public versus university teaching hospital.

METHODS

A retrospective chart review was performed to identify patients with a new diagnosis of DTC from January 1, 2007, to January 1, 2010, in a large public and adjoining university teaching hospital at a single academic medical center. Medical records were reviewed for demographics, pathology, and American Joint Committee on Cancer tumor-node-metastasis stage at initial presentation.

RESULTS

There were 49 cases of well-DTC (96% papillary and 4% Hürthle) in the public hospital and 370 cases (95% papillary, 2% Hürthle, and 3% follicular) in the university teaching hospital. Median age (years) at presentation was 50 in the public versus 48 in the university teaching hospital (p=0.39). Ninety-six percent of public hospital patients were from ethnic minorities compared with 16% of university teaching hospital patients (p<0.0001). Only 1 (2%) public hospital patient had private insurance compared with 85% of university teaching hospital patients. Tumor status (p=0.002) and stage (p=0.03) were more advanced and extrathyroidal extension (p=0.02) was more prevalent among public hospital patients compared with university teaching hospital patients. In a multivariable analysis, public hospital, male gender, increasing age, advanced tumor status, and the presence of lymphovascular invasion were the best predictors of more advanced disease stage. Public hospital patients were 3.4 times more likely to present with advanced DTC than university teaching hospital patients of the same age, gender, tumor status, and lymphovascular invasion status (95% confidence interval 1.29-8.95).

CONCLUSIONS

In a public hospital, where the patient population is defined primarily by insurance status, patients were more likely to present with advanced-stage DTC than patients presenting to an adjacent university teaching hospital. These results suggest a disparity in the stage on initial presentation of DTC, possibly resulting in a delayed diagnosis of cancer.

Thyroid cancer: is ethnicity relevant?

Objective:

This study aimed to determine the age at which various ethnic groups present with thyroid cancer.

Method:

Retrospective, observational study based at three district general hospitals in the West Midlands, serving a widely diverse ethnic population. We assessed all patients undergoing an operative or core biopsy procedure for a thyroid nodule from 1 January 1998 to 31 December 2009. Only patients diagnosed with thyroid cancer were included. Variables examined included the patient's ethnic origin, sex and age at presentation.

Result:

We identified 263 patients diagnosed with thyroid cancer. Papillary carcinoma predominated. Ethnicity was categorised as Caucasian, Asian, black or other. Thyroid cancer was predominantly seen in women, in all ethnic groups. The mean age of thyroid cancer presentation was 50 years in Asians and 56 years in Caucasians, for both sexes combined. The mean presentation age of Asian women was significantly younger (46 years) than that of Caucasian women (56 years) (p = 0.01).

Conclusion:

In this population, Asian women presented with thyroid cancer at a significantly younger mean age than Caucasian women.

Papillary thyroid cancer incidence rates vary significantly by birthplace in Asian American women

OBJECTIVE

To investigate how birthplace influences the incidence of papillary thyroid cancer among Asian American women.

METHODS

Birthplace- and ethnic-specific age-adjusted and age-specific incidence rates were calculated using data from the California Cancer Registry for the period 1988-2004. Birthplace was statistically imputed for 30% of cases using a validated imputation method based on age at Social Security number issuance. Population estimates were obtained from the US Census. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated for foreign-born vs. US-born women.

RESULTS

Age-adjusted incidence rates of papillary thyroid cancer among Filipina (13.7 per 100,000) and Vietnamese (12.7) women were more than double those of Japanese women (6.2). US-born Chinese (IRR = 0.48, 95% CI: 0.40-0.59) and Filipina women (IRR = 0.74, 95% CI: 0.58-0.96) had significantly higher rates than those who were foreign-born; the opposite was observed for Japanese women (IRR = 1.55, 95% CI: 1.17-2.08). The age-specific patterns among all foreign-born Asian women and US-born Japanese women showed a slow steady increase in incidence until age 70. However, among US-born Asian women (except Japanese), substantially elevated incidence rates during the reproductive and menopausal years were evident.

CONCLUSIONS

Ethnic- and birthplace-variation in papillary thyroid cancer incidence can provide insight into the etiology of this increasingly common and understudied cancer.

Risk factors and a predictive model for thyroid cancer in Korean women

BACKGROUND

Thyroid cancer incidence in Korean women has increased radically and is the highest in all cancer types. However, the rate of cancer screening among women is very low.

OBJECTIVE

The aim of the study was to determine the risk factors for thyroid cancer and to develop a predictive model based on these risk factors.

METHODS

The study design comprised a literature review and a case-control study. To construct a predictive model, the participants selected were 260 female outpatients diagnosed with malignant neoplasm of thyroid gland who had undergone thyroid removal surgery. A total of 259 people for the control group were selected by adopting a 5-year age-matching method.

RESULTS

From the literature review, 6 categories of risk factors were identified. Nine variables, including occupation, live(d) in coastal region, family history of thyroid cancer, history of benign thyroid tumor, menopause status and weight gain, number of full-term deliveries, abortion, exercise intensity, and stress, remained as statistically significant risk factors in the stepwise regression model. Regarding the predictive power of the model, the area under the receiver operating characteristic curve was .79, accuracy was .77, sensitivity was .89, specificity was .65, positive predictive value was .72, and negative predictive value was .85.

CONCLUSION

The predictive power of the model was relatively good, so it can be used to identify individuals at high risk for thyroid cancer.

IMPLICATIONS FOR PRACTICE

The predictive model can be used in promoting to participate in early cancer-screening tests. Thus, it will be possible to detect thyroid cancer in its earliest stage, diminish mortality, and improve quality of life.

Thyroid cancer in the Middle Eastern population of California

OBJECTIVE

To describe and compare the epidemiology of thyroid cancer in the rapidly growing Middle Eastern (ME) population and the non-Hispanic, non-Middle Eastern White (NHNMW) residents of California. Population with ME heritage that is officially not recognized as a distinct ethnicity has rarely been studied in the past.

METHODS

ME cases in the California cancer registry files for 1988-2004 were identified by surname recognition. ME population was estimated by ancestry from census data.

RESULTS

Thyroid cancer in ME group, 869 cases and 56 deaths were compared with 19,182 cases and 1,327 deaths in the NHNMW population. Age-adjusted rate ratio (RR) for incidence was 1.5 (95% CI 1.3-1.7) in men and 1.5 (95% CI 1.4-1.7) in women. RR for mortality was 1.4 (95% CI 0.9-2.4) in men and 2.3 (95% CI 1.4-3.9) in women. Papillary tumors comprised over 80% of all cases and their pattern correlated with the rapid increase in thyroid cancer in recent years. Five-year observed survival in ME men was significantly higher than in NHNMW men, but similar in women.

CONCLUSIONS

Eighty-five percent of ME cases identified in this study were born in the Middle East. The higher incidence of thyroid cancer in this immigrant population may largely reflect a combination of sequels of radiation treatment for fungal diseases of the scalp that was common in the area in early 1950s, benign proliferative thyroid disease that is common in the area due to dietary iodine imbalance, and possibly genetic predisposition.

Health of foreign-born people in the United States: a review

This paper identifies the overarching patterns of immigrant health in the US. Most studies indicate that foreign-born individuals are in better health than native-born Americans, including individuals of the same race/ethnicity. They tend to have lower mortality rates and are less likely to suffer from circulatory diseases, overweight/obesity, and some cancers. However, many foreign-born groups have higher rates of diabetes, some infections, and occupational injuries. There is heterogeneity in health among immigrants, whose health increasingly resembles that of natives with duration of US residence. Prospective studies are needed to better understand migrant health and inform interventions for migrant health maintenance.

The thyroid dose burden in medical imaging A re-examination

Radiation is the best defined causative factor in thyroid cancer. The thyroid is especially susceptible to injury from radiation to which it may be exposed in a variety of circumstances in addition to natural background: radiotherapy, including, historically, therapy of such benign conditions as ring worm and haemangiomata, radiation exposure in nuclear accidents and fallout from nuclear bomb tests, and diagnostic exposures, particularly in the relatively high dose CT examination of head and neck. Both use of CT and the incidence of thyroid cancer appear to be increasing worldwide and it has been suggested that there may be a causative relationship between the two. It has been further posited that the iodine content of the thyroid might play a role in increasing the radiation dose absorption. Indeed, on the same basis, iodine administered in the form of an X-ray contrast-enhancing agent might also be expected to play some role in increasing thyroid radiation absorption resulting in a yet higher dose burden in any give circumstances than is generally assumed. In view of the importance of these ideas we have performed some calculations to estimate the magnitude of the iodine effects. We conclude that they are not great enough to cause concern.

Cancer incidence among Korean-American immigrants in the United States and native Koreans in South Korea

BACKGROUND

While previous studies demonstrated contrasting patterns of cancer risk among migrant populations from different ethnic groups in the United States, few studies have focused on the Korean-American population. This study compares cancer incidence rates between Korean-Americans, whites, and blacks in the United States and native Koreans.

METHODS

Data from the Surveillance, Epidemiology, and End Results (SEER) program and International Association for Research on Cancer were used to calculate age-standardized incidence rates among whites, blacks, and Korean Americans in the United States and native Koreans.

RESULTS

The risk of stomach, liver, gallbladder, larynx, and esophageal cancer has sharply declined in Korean-American men compared with their native counterparts while prostate, colon, and rectum cancer risk has increased. In women, stomach, liver, gallbladder, and cervical cancers have declined, and breast, lung, colon, rectum, and endometrial cancers have increased. Cancer rates for stomach, liver, gallbladder, and esophagus are higher in native Koreans compared to US whites. Recently, cancer rates for Korean-American immigrants have increased for prostate, breast, colon, and rectal cancers.

CONCLUSIONS

The study provides evidence that the risk of cancers common in Western countries is higher for Korean Americans than for their native counterparts. Recent trends among Korean Americans also revealed a stronger Western profile.

The thyroid cancer epidemic: is it the dark side of the CT revolution?

The rapid increase in CT use since 1990 and especially in the past 10 years has been accompanied by a coterminous worldwide increase in incidence of thyroid cancer especially in women. Are the two trends independent or related? Specific information from many countries and seven American states suggest that the relationship is real as no other cause can account fully for the temporal change in the frequency of this malignancy. Moreover, newer techniques of CT performance with or without the administration of iodinated contrast material favor the likelihood of a contingent association of image test utilization and thyroid cancer induction.

Quality of cancer registry birthplace data for Hispanics living in the United States

Patient birthplace from the SEER population-based cancer registries is potentially useful for identifying disparities in cancer occurrence and for studying cancer etiology. However, for Hispanics, completeness and accuracy of registry birthplace is unknown. By comparing registry birthplace to self-reported birthplace from 13 interview studies, we determined the completeness and accuracy of this variable and the associations of these measures with patient and hospital characteristics in the Greater Bay Area. Registry birthplace was unrecorded for 46% of 1277 Hispanic cancer cases, and unrecorded birthplace (i.e., incompleteness) was associated with younger age, higher education, English language preference, US birthplace, and admission at certain hospitals. For 691 Hispanics with available registry birthplace, sensitivity and positive predictive value compared to self-report (i.e., accuracy) were 96.3 and 97.3 among foreign-born, and 96.8 and 95.6 among US-born. US-born Hispanics misclassified in the registry as foreign-born were more likely to have unavailable education information, be deceased, prefer a language besides English, and be diagnosed at a smaller hospital or before 1996. Among self-reported foreign-born Hispanics, those misclassified as US-born were less likely to have been diagnosed at an HMO. Although the completeness and accuracy of birthplace information may vary across registries, this variable appears to be limited for analyses involving Hispanics.

Annual report to the nation on the status of cancer (1973 through 1998), featuring cancers with recent increasing trends

BACKGROUND

The American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries, and the Centers for Disease Control and Prevention, including the National Center for Health Statistics (NCHS), collaborate to provide an annual update on cancer occurrence and trends in the United States. This year's report contains a special feature that focuses on cancers with recent increasing trends.

METHODS

From 1992 through 1998, age-adjusted rates and annual percent changes are calculated for cancer incidence and underlying cause of death with the use of NCI incidence and NCHS mortality data. Joinpoint analysis, a model of joined line segments, is used to examine long-term trends for the four most common cancers and for those cancers with recent increasing trends in incidence or mortality. Statistically significant findings are based on a P value of.05 by use of a two-sided test. State-specific incidence and death rates for 1994 through 1998 are reported for major cancers.

RESULTS

From 1992 through 1998, total cancer death rates declined in males and females, while cancer incidence rates declined only in males. Incidence rates in females increased slightly, largely because of breast cancer increases that occurred in some older age groups, possibly as a result of increased early detection. Female lung cancer mortality, a major cause of death in women, continued to increase but more slowly than in earlier years. In addition, the incidence or mortality rate increased in 10 other sites, accounting for about 13% of total cancer incidence and mortality in the United States.

CONCLUSIONS

Overall cancer incidence and death rates continued to decline in the United States. Future progress will require sustained improvements in cancer prevention, screening, and treatment.

Risk of cancer in migrants and their descendants in Israel: II. Carcinomas and germ-cell tumours

Cancer registrations among young individuals (under age 30 years) for a 30-year period (1960-1989) were used to investigate the risk of cancer in migrants to Israel, and in their offspring, relative to Israel-born individuals with Israel-born parents. Relative risks of testis and ovarian cancer (germ cell tumours and carcinomas), melanoma, and carcinomas of nasopharynx, colorectum, breast, cervix and thyroid were calculated according to father's birthplace, and odds ratios for birthplace of mother, or of both parents. The estimates were adjusted for the effects of age, sex and time period. For 3 cancers, i.e., testis cancer, nasopharyngeal carcinoma and melanoma, there were quite large differences in incidence, which persisted to some degree into the second generation, suggesting that inherited susceptibility may underlie some of the variation. For ovarian, colorectal, cervical and thyroid cancers, differences in risk between the migrant groups had largely disappeared in their offspring, suggesting that environmental exposures, which were modified by migration, are the major causative factors.

Time trend and age-period-cohort effect on incidence of thyroid cancer in Connecticut, 1935-1992

Recent studies from Europe suggest a continuing increase in thyroid cancer, but it is unclear whether this trend also applies to the United States. The current study examined the long-term trend of thyroid cancer in Connecticut. Our results show that the overall age-adjusted incidence rate of thyroid cancer has been increasing in Connecticut, from 1.30/100,000 in 1935-1939 to 5.78/100,000 in 1990-1992 in females, and from 0.30/100,000 in 1935-1939 to 2.77/100,000 in 1990-1992 in males. The increase mainly comes from papillary carcinoma of the thyroid. The birth cohort analyses indicate that the increase in thyroid cancer occurred among cohorts born between 1915 and 1945, which experienced an increase of 31.4% every 5 years in males and 17.3% in females over the period 1960-1979. For those born since the 1945 cohort, the incidence has been decreasing, at rates of 9.3% and 8.3% every 5 years over the period 1975-1992 in males and females, respectively. Age-period-cohort modeling results also suggest a strong birth cohort effect on the observed time trend in both sexes, which closely follows the introduction of radiation treatment of benign childhood conditions in the head and neck between 1920 and the 1950s in the United States. Our results are consistent with the suggested radiation hypothesis, indicating that radiation treatment of benign childhood conditions in the head and neck is largely responsible for the observed increase of thyroid cancer in Connecticut.