Recent trends in breast cancer incidence among 6 Asian groups in the Greater Bay Area of Northern California

Changes in Breast Cancer Risk and Risk Factor Profiles among U.S.-Born and Immigrant Asian American Women Residing in the San Francisco Bay Area

BACKGROUND

Breast cancer incidence rates in women of Asian descent have been increasing in the United States and Asia.

METHODS

In a case-control study of Asian American women from the San Francisco Bay Area, we assessed associations with birthplace and migration-related characteristics and compared risk factors between Asian American and non-Hispanic White women by birthplace and birth cohort.

RESULTS

Birthplace and migration-related characteristics were associated with breast cancer risk only among women in the younger birth cohort (1951-1984) that comprised 355 cases diagnosed at age ≤55 years and 276 sister and population controls. Breast cancer risk was marginally increased among foreign-born women [OR = 1.40; 95% confidence interval (CI), 0.97-2.03] and two-fold among foreign-born Chinese women (OR = 2.16; 95% CI, 1.21-3.88). Two-fold increased risks were associated with migration at age ≥40 years and longer U.S. residence (≥30 years or ≥75% of life). The education level was high among both cases and controls. Differences in the prevalence of risk factors by birthplace and birth cohort suggest temporal changes in reproductive and lifestyle-related factors. The prevalence in risk factors was similar between foreign-born and U.S.-born women in the younger birth cohort, and did not fully explain the observed associations with birthplace and other migration characteristics.

CONCLUSIONS

In contrast to studies from earlier decades, younger foreign-born Asian American women had a higher risk of breast cancer than U.S.-born Asian American women.

IMPACT

It is important and urgent to understand what factors drive the increasing burden of breast cancer in women of Asian descent and implement effective prevention programs.

Elevated breast cancer mortality among highly educated Asian American women

Background

Postmenopausal breast cancer (PMBC) is the most commonly diagnosed and the second leading cause of cancer death among women in the US. Research examining the association between PMBC and education level has been inconsistent; no study in the US has examined how educational level impacts PMBC mortality in Asian American women, a largely immigrant population with above-average educational attainment.

Methods

California Vital Statistics data from 2012–2017 were analyzed to derive age-adjusted mortality rate ratios (MRRs) by education level (associates degree or above referred to as “higher education”, high school, less than high school) and race [Non-Hispanic White (NHW), Asian/Pacific Islander (Asian), and its two largest subpopulations: Chinese and Filipino] from negative binomial regression models.

Results

PMBC mortality for both NHWs and Asians was greater among women with higher education compared to those who did not complete high school: NHWs had 22% higher PMBC mortality (MRR 1.22; 95% CI: 1.14–1.31) and Asians had 2.6 times greater PMBC mortality (MRR 2.64; 95% CI: 2.32–3.00) than their counterparts who did not complete high school. Asians in the lowest education level had 70% lower mortality than NHWs (MRR 0.30; 95% CI: 0.27–0.34). This mortality advantage among Asians was greatly reduced to only 27% lower among the highest educated (MRR 0.73; 95% CI: 0.68–0.78). For higher educated Filipina women, no mortality advantage was evident compared to NHWs (MRR 0.96; 95% CI: 0.88–1.05).

Conclusion

PMBC mortality for higher educated Asian women is elevated in comparison to their counterparts with less education. Given that PMBC survival is greater among those with higher education, our findings strongly suggest an excess in the incidence of PMBC (more than double) among higher educated Asian women; this warrants more research into potentially modifiable causes of PMBC in this burgeoning population.

Breast cancer incidence trends in Asian women aged 20 or older as compared to other ethnic women in the United States from 2000 to 2018 by time period, age and tumor stage

BACKGROUND

After new cancer data are released in April 2021, it is important to update the incidence trend in breast cancer from 2000 to 2018 and focus on ethnic disparities in the risk of developing breast cancer.

METHODS

We identified 1129,564 women who were diagnosed with incident breast cancer at age ≥ 20 in 2000-2018 from 18 SEER (Surveillance, Epidemiology, and End Results) registries. We utilized the SEER*Stat software to calculate age-adjusted incidence rates.

RESULTS

Overall age-adjusted incidence rate of breast cancer was the highest in non-Hispanic white (NHW) women (190.4 cases per 100,000 women), followed by NH-black (NHB) (178.4), Asian/Pacific-Islanders (API) (141.3), Hispanic (133.3) and American-Indians/Alaska-Native (AIAN) women (128.8). Annual percentage change (APC) from 2000 to 2018 showed that annual increase was statistically significant for API (APC: 1.0, 95% CI: 0.8-1.3), NHB (APC: 0.5, 0.2-0.7), AIAN (1.6, 1.1-2.2), and Hispanic women (0.4, 0.2-0.7), but annual percentage of incidence did not significantly decrease for NHW (-0.1, -0.4 to -0.1). Incidence rates of hormone-receptor positive breast cancer increased from 2000 to 2018 in all ethnic women, while incidence rates of hormone-receptor negative breast cancer decreased. NHW and NHB women had a significantly higher risk of having breast cancer than API women. In 2012-2018, the risks of having local stage and distant stage breast cancer for NHW (1.31, 1.29-1.33 and 1.19, 1.16-1.21) and NHB (1.09, 1.07-1.11 and 1.31, 1.28-1.35) women were significantly higher than that of API women.

CONCLUSIONS

The incidence of hormone-receptor positive breast cancer increased in all ethnic women from 2000 to 2018 while the incidence of hormone-receptor negative breast cancer decreased. There were still substantial racial disparities in breast cancer incidences.

Association of Cancer History and Health Care Utilization Among Female Immigrants Using NHANES 2007-2016 Data

BACKGROUND

Despite health disparities in preventive care among adult female immigrants, the extent to which their health service utilization is influenced by a cancer history remains largely unknown.

METHODS

Using Andersen's behavioral model, 2007-2016 National Health and Nutrition Examination Survey data were analyzed to examine the influence of a cancer history on health service utilization among adult immigrant women. Multivariate logistic regression models assessed factors related to past year health care utilization, operationalized as an outpatient doctor's visit and an inpatient overnight hospital stay.

RESULTS

Once other factors were considered, a past cancer history increased the likelihood of a past year inpatient overnight hospital stay, but was not associated with a past year outpatient doctor's visit.

DISCUSSION

An outpatient doctor's visit for adult female immigrant cancer survivors would provide an opportunity for essential preventive health services. They must be educated about the importance of ongoing outpatient care for cancer surveillance and health maintenance.

Higher Breast Cancer Risk Among Immigrant Asian American Women Than Among US-Born Asian American Women

INTRODUCTION

Given rising rates of breast cancer in parts of Asia, immigrant Asian American women in the United States may have higher rates of breast cancer than previously anticipated. This study examined breast cancer risk among Asian American women by nativity and percentage of life lived in the United States, accounting for established breast cancer risk factors.

METHODS

We analyzed a breast cancer case-control data set of Asian American women living in the San Francisco Bay Area; this data set included 132 cases of women with breast cancer selected from a Surveillance, Epidemiology, and End Results cancer registry and 438 Asian American women without diagnosed breast cancer matched to cases by age and country of origin. We used logistic regression to compare 3 Asian American groups: US-born, immigrants who lived 50% or more of their life in the United States, and immigrants who lived less than 50% of their life in the United States.

RESULTS

In the minimally adjusted and fully adjusted models, both groups of immigrant Asian American women had higher risk of breast cancer than US-born Asian American women. In the fully adjusted model, compared with US-born Asian American women, immigrant Asian American women who lived more than 50% of their life in United States were on average 3 times as likely (odds ratio = 3.00; 95% confidence interval, 1.56-5.75) and immigrants who lived less than 50% of their life in United States were on average 2.46 times as likely (odds ratio = 2.46; 95% confidence interval, 1.21-4.99) to have breast cancer. We found no difference in fully adjusted odds ratios of having breast cancer between the 2 immigrant groups.

CONCLUSION

This study provides preliminary evidence that breast cancer risk among immigrant Asian American women may be higher than among their US-born counterparts.

Integrative Comparison of mRNA Expression Patterns in Breast Cancers from Caucasian and Asian Americans with Implications for Precision Medicine

Asian Americans (AS) have significantly lower incidence and mortality rates of breast cancer than Caucasian Americans (CA). Although this racial disparity has been documented, the underlying pathogenetic factors explaining it are obscure. We addressed this issue by an integrative genomics approach to compare mRNA expression between AS and CA cases of breast cancer. RNA-seq data from the Cancer Genome Atlas showed that mRNA expression revealed significant differences at gene and pathway levels. Increased susceptibility and severity in CA patients were likely the result of synergistic environmental and genetic risk factors, with arachidonic acid metabolism and PPAR signaling pathways implicated in linking environmental and genetic factors. An analysis that also added eQTL data from the Genotype-Tissue Expression Project and SNP data from the 1,000 Genomes Project identified several SNPs associated with differentially expressed genes. Overall, the associations we identified may enable a more focused study of genotypic differences that may help explain the disparity in breast cancer incidence and mortality rates in CA and AS populations and inform precision medicine. Cancer Res; 77(2); 423-33. ©2016 AACR.

Cancer statistics for Asian Americans, Native Hawaiians, and Pacific Islanders, 2016: Converging incidence in males and females

Cancer is the leading cause of death among Asian Americans, Native Hawaiians, and Pacific Islanders (AANHPIs). In this report, the American Cancer Society presents AANHPI cancer incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. Among AANHPIs in 2016, there will be an estimated 57,740 new cancer cases and 16,910 cancer deaths. While AANHPIs have 30% to 40% lower incidence and mortality rates than non-Hispanic whites for all cancers combined, risk of stomach and liver cancers is double. The male-to-female incidence rate ratio among AANHPIs declined from 1.43 (95% confidence interval, 1.36-1.49) in 1992 to 1.04 (95% confidence interval, 1.01-1.07) in 2012 because of declining prostate and lung cancer rates in males and increasing breast cancer rates in females. The diversity within the AANHPI population is reflected in the disparate cancer risk by subgroup. For example, the overall incidence rate in Samoan men (526.5 per 100,000) is more than twice that in Asian Indian/Pakistani men (216.8). Variations in cancer rates in AANHPIs are related to differences in behavioral risk factors, use of screening and preventive services, and exposure to cancer-causing infections. Cancer-control strategies include improved use of vaccination and screening; interventions to increase physical activity and reduce excess body weight, tobacco use, and alcohol consumption; and subgroup-level research on burden and risk factors. CA Cancer J Clin 2016;66:182-202. © 2016 American Cancer Society.

Birthplace and esophageal cancer incidence patterns among Asian-Americans

The incidence of esophageal adenocarcinoma in the United States has risen rapidly over the last 30 years, whereas the incidence of esophageal squamous cell carcinoma has fallen dramatically. In contrast, parts of Asia have extremely high rates of squamous cell carcinoma, but virtually no adenocarcinoma. Within the United States, Asian-Americans as a whole, have low rates of esophageal adenocarcinoma and higher rates of squamous cell carcinoma. It is unclear what the patterns are for those Asians born in the United States. The relative influence of ethnicity and environment on the incidence of esophageal cancer in this population is unknown. We identified all cases of esophageal adenocarcinoma and squamous cell carcinoma from the California Cancer Registry 1988-2004, including 955 cases among 6 different Asian ethnicities. Time trends were examined using Joinpoint software to calculate the annual percentage changes in regression models. Rates of esophageal squamous cell carcinoma varied substantially among different Asian ethnic groups, but squamous cell carcinoma was much more common than adenocarcinoma in both foreign-born and US-born Asian-Americans. Rates of squamous cell carcinoma were slightly higher among US-born Asian men (4.0 per 100,000) compared with foreign-born Asian men (3.2 per 100,000) and White men (2.2 per 100,000), P = 0.03. Rates of adenocarcinoma were also slighter higher among US-born Asian men (1.2 per 100,000) compared with foreign-born Asian men (0.7 per 100,000), P = 0.01. Rates of squamous cell carcinoma decreased for both US-born and foreign-born Asians during this period, whereas adenocarcinoma remained low and stable. These results provide better insight into the genetic and environmental factors affecting the changing incidence of esophageal cancer histologies in the United States and Asia.

Disaggregating data on Asian American and Pacific Islander women to provide new insights on potential exposures to hazardous air pollutants in California

BACKGROUND

The Asian American and Pacific Islander (AAPI) population is heterogeneous and rapidly growing in the United States, with a high proportion concentrated in California. Although traditionally assumed to have lower rates of breast cancer than non-Hispanic white women, recent studies have suggested considerable variation in incidence by AAPI ethnic group, with rates in some exceeding those in non-Hispanic whites. The potential role of environmental toxicants has not been well explored and may provide insights into these patterns.

METHODS

We created an exposure potential index (EPI) score for 24 hazardous air pollutants modeled by the U.S. Environmental Protection Agency National-Scale Air Toxics Assessment considered to be mammary gland carcinogens, and compared values at the census tract level for "geographically concentrated" AAPI groups throughout the State. "Geographically concentrated" populations were defined as census tracts with at least 100 individuals from a specified racial/ethnic population as enumerated by the 2000 Census.

RESULTS

Although EPI scores differed little between census tracts with aggregated AAPI (mean EPI = 0.53) and non-Hispanic white women (mean EPI = 0.63), there was substantial variation between tracts for disaggregated AAPI groups, with notably higher EPI scores for tracts enumerated for Korean or Japanese women (mean EPI of 0.78 and 0.77, respectively) compared with other AAPI groups.

CONCLUSIONS

Our findings underscore the importance of disaggregating data for the heterogeneous AAPI population to identify differences in potential environmental exposures across groups.

IMPACT

Future cancer etiology studies should examine environmental exposure differences within and across groups for the diverse AAPI population.

Colorectal cancer among Koreans living in South Korea versus California: incidence, mortality, and screening rates

OBJECTIVES

This study compared trends in colorectal cancer (CRC) incidence and mortality rates among Koreans in South Korea and Korean Americans and non-Hispanic whites in California between 1999 and 2009, and examined CRC screening rates and socio-demographic correlates of CRC screening in the two Korean populations.

DESIGN

Age-standardized CRC incidence and mortality rates of Koreans in South Korea and Korean Americans and non-Hispanic whites in California for the years 1999-2009 were obtained from annual reports of cancer statistics and modeled using joinpoint regression. Using 2009 data from the Korean National Health and Nutrition Examination Survey and the California Health Interview Survey, we estimated and compared CRC screening rates and test modalities. We used multiple logistic regression to examine socio-demographic correlates of completion of CRC screening according to the guidelines among the two Korean populations.

RESULTS

CRC incidence and mortality rates among South Koreans increased during 1999-2009 but more slowly during the late 2000s. In California, CRC incidence increased among Korean American females but decreased among non-Hispanic whites. About 37% of South Koreans and 60% of Korean Americans reported completion of CRC screening according to guidelines in 2009. Among South Koreans, married status, higher income, and private health insurance were associated with CRC screening, adjusting for other factors. Among Korean Americans, having health insurance was associated with CRC screening.

CONCLUSION

Despite almost identical CRC screening guidelines in South Korea and the USA and substantially higher screening rates among Korean Americans as compared to South Koreans, disparities remain in both populations with respect to CRC statistics. Thus, efforts to promote primary and secondary prevention of CRC in both Korean populations are critically important in both countries.

Impact of socioeconomic status and ethnic enclave on cervical cancer incidence among Hispanics and Asians in California

OBJECTIVE

This study aimed to evaluate the incidence of cervical cancer by nativity [United States (US) versus non-US], neighborhood socioeconomic status and ethnic enclave among Hispanics and Asians in California.

METHODS

Using data from the California Cancer Registry, information on all primary invasive cervical cancer (Cca) patients diagnosed in California from January 1, 1990 through December 31, 2004 was obtained. We analyzed the influence of enclave, socioeconomic status and nativity on Cca incidence.

RESULTS

Among the 22,189 Cca cases diagnosed between 1990 and 2004, 50% were non-Hispanic white, 39% Hispanic and 11% Asian women, and 63% US-born. Seventy percent of the Cca cases were squamous cell carcinoma, 19% adenocarcinoma and 11% other histologies. Higher incidence of Cca was observed in high enclave (76%) and low socioeconomic status (70%) neighborhoods. By ethnic group, US-born women showed lower rates of squamous cell carcinoma compared to foreign-born women. Hispanics living in low socioeconomic and high enclave had 12.7 times higher rate of Cca than those living in high socioeconomic, low enclave neighborhoods. For Asian women incidence rates were 6 times higher in the low socioeconomic, high enclave neighborhoods compared to those living in high socioeconomic, low enclave neighborhoods.

CONCLUSION

More targeted outreach to increase Pap smear screening and human papilloma virus vaccination for women living in high enclave neighborhoods can help decrease the incidence of Cca in these groups of women.

Association of race/ethnicity, socioeconomic status, and breast cancer subtypes in the National Cancer Data Base (2010-2011)

To estimate the odds of breast cancer subtypes in minority populations versus non-Hispanic (NH) whites stratified by socioeconomic status (SES) [a composite of individual-level SES (insurance status) and area-level SES (median household income quartile from 2000 U.S. Census data)] using a large nationwide cancer database. We used the National Cancer Data Base to identify breast cancer cases diagnosed in 2010 and 2011, the only 2 years since U.S. cancer registries uniformly began collecting HER2 results. Breast cancer cases were classified into five subtypes based on hormone receptor (HR) and HER2 status: HR+/HER2-, HR+/HER2+, HR-/HER2+ (HER2-overexpressing), HR-/HER2- (TN), and unknown. A polytomous logistic regression was used to estimate odds ratios (ORs) comparing the odds of non-HR+/HER2-subtypes to HR+/HER2- for racial/ethnic groups controlling for and stratifying by SES, using a composite of insurance status and area-level income. Compared with NH whites, NH blacks and Hispanics were 84 % (OR = 1.84; 95 % CI 1.77-1.92) and 17 % (OR = 1.17; 95 % CI 1.11-1.24) more likely to have TN subtype versus HR+/HER2-, respectively. Asian/Pacific Islanders (API) had 1.45 times greater odds of being diagnosed with HER2-overexpressing subtype versus HR+/HER2- compared with NH whites (OR = 1.45; 95 % CI 1.31-1.61). We found similar ORs for race in high and low strata of SES. In a large nationwide hospital-based dataset, we found higher odds of having TN breast cancer in black women and of HER2-overexpressing in API compared with white women in every level of SES.

Colorectal cancer incidence in Asian populations in California: effect of nativity and neighborhood-level factors

OBJECTIVES

Heritable and environmental factors may contribute to differences in colorectal cancer (CRC) incidence across populations. We capitalized on the resources of the California Cancer Registry (CCR) and California's diverse Asian population to perform a cohort study exploring the relationships between CRC incidence, nativity, and neighborhood-level factors across Asian subgroups.

METHODS

We identified CRC cases in the CCR from 1990 to 2004 and calculated age-adjusted CRC incidence rates for non-Hispanic Whites and US-born vs. foreign-born Asian ethnic subgroups, stratified by neighborhood socioeconomic status (SES) and "ethnic enclave." Trends were studied with joinpoint analysis.

RESULTS

CRC incidence was lowest among foreign-born South Asians (22.0/100,000; 95% confidence interval (CI): 19.7-24.5/100,000) and highest among foreign-born Japanese (74.6/100,000; 95% CI: 70.1-79.2/100,000). Women in all Asian subgroups except Japanese, and men in all Asian subgroups except Japanese and US-born Chinese, had lower CRC incidence than non-Hispanic Whites. Among Chinese men and Filipino women and men, CRC incidence was lower among foreign-born than US-born persons; the opposite was observed for Japanese women and men. Among non-Hispanic Whites, but not most Asian subgroups, CRC incidence decreased over time. CRC incidence was inversely associated with neighborhood SES among non-Hispanic Whites, and level of ethnic enclave among Asians.

CONCLUSIONS

CRC incidence rates differ substantially across Asian subgroups in California. The significant associations between CRC incidence and nativity and residence in an ethnic enclave suggest a substantial effect of acquired environmental factors. The absence of declines in CRC incidence rates among most Asians during our study period may point to disparities in screening compared with Whites.

What factors explain disparities in mammography rates among Asian-American immigrant women? A population-based study in California

BACKGROUND

The purpose of this study was to compare rates of screening mammography among immigrant women in five Asian-American ethnic groups in California, and ascertain the extent to which differences in mammography rates among these groups are attributable to differences in known correlates of cancer screening.

METHODS

Using 2009 data from the California Health Interview Survey, we compared the rates of mammography among Chinese, Filipino, Japanese, Korean, and Vietnamese immigrants 40 years and older. To assess the impact of Asian ethnicity on participation in screening, we performed multiple logistic regression analysis with models that progressively adjusted for acculturation, sociodemographic characteristics, access to health care, and breast cancer risk factors, and examined the predicted probabilities of screening after adjusting for these factors.

FINDINGS

Participation in screening mammography differed according to ethnicity, with Filipina and Vietnamese Americans having the highest rates and Korean Americans having the lowest rates of lifetime and recent (past 2 years) screening. These differences decreased substantially after adjusting for acculturation, sociodemographic factors, and risk factors of breast cancer, but differences remained, most notably for Korean Americans, who continued to have the lowest predicted probability of screening even after adjustment for these factors.

CONCLUSIONS

This analysis draws attention to low mammography screening rates among Asian-American immigrants, especially recent immigrants who lack health insurance. Given that their breast cancer incidence is rising with length of stay in the United States, it is important to increase regular mammography screening in these groups.

Cancer incidence trends among Asian American populations in the United States, 1990-2008

BACKGROUND

National cancer incidence trends are presented for eight Asian American groups: Asian Indians/Pakistanis, Chinese, Filipinos, Japanese, Kampucheans, Koreans, Laotians, and Vietnamese.

METHODS

Cancer incidence data from 1990 through 2008 were obtained from 13 Surveillance, Epidemiology, End Results (SEER) registries. Incidence rates from 1990 through 2008 and average percentage change were computed using SEER*Stat and Joinpoint software. The annual percentage change (APC) in incidence rates was estimated with 95% confidence intervals (95% CIs) calculated for both the rate and APC estimates. Rates for non-Hispanic whites are presented for comparison.

RESULTS

Prostate cancer was the most common malignancy among most groups, followed by lung, colorectal, liver, and stomach cancers. Breast cancer was generally the most common cancer in women, followed by colorectal and lung cancers; liver, cervix, thyroid, and stomach cancers also ranked highly. Among men, increasing trends were observed for prostate (Asian Indians and Pakistanis: APC 1990-2003 = 2.2, 95% CI = 0.3 to 4.1; Filipinos: APC 1990-1994 = 19.0, 95% CI = 4.5 to 35.4; Koreans: APC 1990-2008 = 2.9, 95% CI = 1.8 to 4.0), colorectal (Koreans: APC 1990-2008 = 2.2, 95% CI = 0.9 to 3.5), and liver cancers (Filipinos: APC 1990-2008 = 1.6, 95% CI = 0.4 to 2.7; Koreans: APC 1990-2006 = 2.1, 95% CI = 0.4 to 3.7; Vietnamese: APC 1990-2008 = 1.6, 95% CI = 0.3 to 2.8), whereas lung and stomach cancers generally remained stable or decreased. Among women, increases were observed for uterine cancer (Asian Indians: APC 1990-2008 = 3.0, 95% CI = 0.3 to 5.8; Chinese: APC 2004-2008 = 7.0, 95% CI = 1.4 to 12.9; Filipina: APC 1990-2008 = 3.0, 95% CI = 2.4 to 3.7; Japanese: APC 1990-2008 = 1.1, 95% CI = 0.1 to 2.0), colorectal cancer (Koreans: APC 1990-2008 = 2.8, 95% CI = 1.7 to 3.9; Laotians: APC: 1990-2008 = 5.9, 95% CI = 4.0 to 7.7), lung cancer (Filipinas: APC 1990-2008 = 2.1, 95% CI = 1.4 to 2.8; Koreans: APC 1990-2008 = 2.1, 95% CI = 0.6 to 3.6), thyroid cancer (Filipinas: APC 1990-2008 = 2.5, 95% CI = 1.7 to 3.3), and breast cancer in most groups (APC 1990-2008 from 1.2 among Vietnamese and Chinese to 4.7 among Koreans). Decreases were observed for stomach (Chinese and Japanese), colorectal (Chinese), and cervical cancers (Laotians and Vietnamese).

CONCLUSIONS

These data fill a critical knowledge gap concerning the cancer experience of Asian American groups and highlight where increased preventive, screening, and surveillance efforts are needed-in particular, lung cancer among Filipina and Korean women and Asian Indian/Pakistani men, breast cancer among all women, and liver cancer among Vietnamese, Laotian, and Kampuchean women and Filipino, Kampuchean, and Vietnamese men.

Cancer incidence trends among native Hawaiians and other Pacific Islanders in the United States, 1990-2008

BACKGROUND

Lack of annual population estimates for disaggregated Native Hawaiian and Other Pacific Islander (NHOPI) populations limits the ability to examine cancer incidence rates and trends to understand the cancer burdens among NHOPIs.

METHODS

Utilizing 1990 and 2000 population census data, we estimated the annual populations by age and sex for Native Hawaiians, Samoans, and Guamanians/Chamorros for 1990-2008 in regions covered by 13 of the National Cancer Institute's SEER registries. Cancer diagnoses during 1990-2008 from these registries were used to calculate the age-adjusted (2000 US Standard) incidence rates by sex, calendar year/period, and cancer type for each population. The annual percentage change (APC) in incidence rates was estimated with the 95% confidence intervals (95% CIs) calculated for both the rate and APC estimates.

RESULTS

Statistically significant declining trends were found in Native Hawaiians, in men for lung and stomach cancers (APC = -2.3%; 95% CI = -3.3 to -1.3; and APC = -3.8%; 95% CI = -6.0 to -1.6, respectively), and in women for breast cancer (APC = -4.1%; 95% CI = -5.7 to -2.5) since 1998 and lung cancer (APC = -6.4%; 95% CI = -10.7 to -1.8) since 2001. Rising incidence trends were experienced by Samoans, especially by Samoan women for breast (APC = 2.7%; 95% CI = 0.9 to 4.5) and uterus (APC = 7.3%; 95% CI = 6.2 to 8.4) cancers. With limited data, Guamanians/Chamorros demonstrated lower, but increasing, incidence rates than other NHOPIs.

CONCLUSIONS

Population-based cancer incidence rates for disaggregated NHOPI populations help identify disparities in cancer burden and provide valuable information to improve cancer control efforts among NHOPIs.

Primary care physicians' cancer screening recommendation practices and perceptions of cancer risk of Asian Americans

Asian Americans experience disproportionate incidence and mortality rates of certain cancers, compared to other racial/ethnic groups. Primary care physicians are a critical source for cancer screening recommendations and play a significant role in increasing cancer screening of their patients. This study assessed primary care physicians' perceptions of cancer risk in Asians and screening recommendation practices. Primary care physicians practicing in New Jersey and New York City (n=100) completed a 30-question survey on medical practice characteristics, Asian patient communication, cancer screening guidelines, and Asian cancer risk. Liver cancer and stomach cancer were perceived as higher cancer risks among Asian Americans than among the general population, and breast and prostate cancer were perceived as lower risks. Physicians are integral public health liaisons who can be both influential and resourceful toward educating Asian Americans about specific cancer awareness and screening information.

Comparison of breast cancer screening rates between Korean women in America versus Korea

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among Korean American women and among Korean women in Korea. However, many Asian women are not aware of the importance of screening mammography. This study compares breast cancer screening in Korean women in California and in Korea.

METHODS

The 2005 California Health Interview Survey (CHIS) and 2005 Korean National Cancer Screening Survey (KNCSS) were used to examine breast cancer screening and related factors. The sample included 252 Korean American women in California and 889 Korean women aged > or = 40 years. Logistic regression was used to predict the odds of having had a screening mammography in the past 2 years. For CHIS data, SUDAAN software (Research Triangle Institute, Research Triangle Park, NC) was used to take into account the design of the complex and multistage samples.

RESULTS

Korean women reported a lower rate than Korean American women of ever having had a screening mammography (50.8% vs. 77.8%). Korean women also had lower rates of having had a screening mammography in the past 2 years than Korean American women (39.5% vs. 57.2%). Korean Americans were less likely to undergo screening mammography if they were older. Korean women were less likely to undergo screening mammography if they were older, unemployed, lacked private cancer insurance, lacked health checkups, did not exercise, had poor health status, or currently smoked.

CONCLUSIONS

We found significant differences in cancer screening behavior in Korean women depending on where they lived. These differences may indicate an important influence of social factors on preventive health behavior.

Comparative analysis of clinicopathologic features, treatment, and survival of Asian women with a breast cancer diagnosis residing in the United States

BACKGROUND

It has been established that disparities by ethnicity in the rates of breast cancer diagnoses and disease-specific survival (DSS) exist in the United States. However, few studies have assessed differences specifically between Asians and other ethnic groups or among Asian subgroups.

METHODS

The authors used the Surveillance, Epidemiology, and End Results database to identify patients who were diagnosed with invasive breast cancer between 1988 and 2008. Clinicopathologic features, treatment, and DSS rates were compared among broad ethnic groups and among Asian subgroups.

RESULTS

In total, there were 658,691 patients in the study, including 511,701 non-Hispanic white (NHW) women (77.7%), 57,890 black women (8.8%), 45,461 Hispanic white (HW) women (6.9%), and 43,639 Asian women (6.6%). The Asian cohort was divided into the following subgroups: Filipino, Chinese, Japanese, Indian/Pakistani, Korean, Vietnamese, Hawaiian/Pacific Islander, and other. Patients in all the Asian subgroups, except Japanese, were younger at diagnosis than NHW patients. After adjustment for disease stage, Japanese patients diagnosed with stage I through III disease had better DSS rates than patients in the NHW group or in the other Asian subgroups. Hawaiian/Pacific Islander patients with stage III or IV disease had worse DSS rates than NHW patients and patients in the other Asian subgroups. All other Asian subgroups had DSS rates similar to the DSS rate in the NHW group. [Formula: see text]

CONCLUSIONS

The current results indicated that disparities exist for Asian women with breast cancer who reside in the United States compared with NHW groups and among Asian subgroups. Differences in presenting clinicopathologic features may affect DSS rates, suggesting that further investigation of these disparities is warranted to increase early detection and treatment for specific subgroups.

Age-specific incidence of breast cancer subtypes: understanding the black-white crossover

BACKGROUND

Breast cancer incidence is higher among black women than white women before age 40 years, but higher among white women than black women after age 40 years (black-white crossover). We used newly available population-based data to examine whether the age-specific incidences of breast cancer subtypes vary by race and ethnicity.

METHODS

We classified 91908 invasive breast cancers diagnosed in California between January 1, 2006, and December 31, 2009, by subtype based on tumor expression of estrogen receptor (ER) and progesterone receptor (PR)-together referred to as hormone receptor (HR)-and human epidermal growth factor receptor 2 (HER2). Breast cancer subtypes were classified as ER or PR positive and HER2 negative (HR(+)/HER2(-)), ER or PR positive and HER2 positive (HR(+)/HER2(+)), ER and PR negative and HER2 positive (HR(-)/HER2(+)), and ER, PR, and HER2 negative (triple-negative). We calculated and compared age-specific incidence rates, incidence rate ratios, and 95% confidence intervals by subtype and race (black, white, Hispanic, and Asian). All P values are two-sided.

RESULTS

We did not observe an age-related black-white crossover in incidence for any molecular subtype of breast cancer. Compared with white women, black women had statistically significantly higher rates of triple-negative breast cancer at all ages but statistically significantly lower rates of HR(+)/HER2(-) breast cancers after age 35 years (all P < .05). The age-specific incidence of HR(+)/HER2(+) and HR(-)/HER2(+) subtypes did not vary markedly between white and black women.

CONCLUSIONS

The black-white crossover in breast cancer incidence occurs only when all breast cancer subtypes are combined and relates largely to higher rates of triple-negative breast cancers and lower rates of HR(+)/HER2(-) breast cancers in black vs white women.

Low rates of hepatitis B virus screening at the onset of chemotherapy

PURPOSE

Patients with hepatitis B virus (HBV) infection are at risk for reactivation after chemotherapy. Effective prophylaxis is available but depends on detection of prior infection. Previous studies have shown low screening rates, but no large-scale US studies have been conducted. We sought to determine predictors of screening and positive HBV test results in patients receiving chemotherapy.

METHODS

We conducted a retrospective cohort study of patients with newly diagnosed cancer who received chemotherapy between January 2004 and September 2007 at a comprehensive cancer center. We determined rates and predictors of screening for HBV infection with HB surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc) tests as well as the prevalence and predictors of positive results. We explored rates of acutely elevated liver function tests and liver decompensation after chemotherapy.

RESULTS

Of 10,729 new patients who received chemotherapy, 1,787 (16.7%) underwent HBsAg or anti-HBc screening. Less than 20% of patients with HBV risk factors were screened, even though their odds of HBV infection were increased four-fold compared with those without risk factors. The prevalence of chronic HBV infection was 1.5%. whereas 7.4% had positive anti-HBc only. The strongest predictors of HBV screening were having a history of HBV infection, hematologic malignancy, and rituximab treatment (P < .001). Asian ethnicity was not a significant predictor of screening, despite being a strong and highly significant predictor of positive test results (P < .001).

CONCLUSION

HBV screening among patients with cancer is low, especially among those known to be at high risk for HBV infection. Future research directed toward identifying best screening methods and HBV risk tools will be necessary to reduce the risk of reactivation of HBV infection after chemotherapy.

Findings from focus groups indicating what Chinese American immigrant women think about breast cancer and breast cancer screening

OBJECTIVES

To explore beliefs of Chinese American, immigrant women related to breast cancer and mammography.

DESIGN

Qualitative description with semistructured focus groups.

SETTING

Metropolitan Portland, Oregon.

PARTICIPANTS

Thirty eight foreign-born Chinese women, age 40 and older, in five focus groups.

METHODS

Focus group discussions in Chinese were audiotaped, transcribed, and translated into English. Using a process of directed content analysis, group transcripts were coded for themes based on the discussion guide.

RESULTS

Three main themes emerged from the analysis: knowledge and beliefs; support, communication, and educational needs; and access to care. Subthemes included beliefs such as barriers and facilitators to screening and perceptions about personal breast cancer risk. Several women were profoundly affected by the negative breast cancer-related experiences of relatives and friends. Some common myths remain about causes and treatment of breast cancer.

CONCLUSIONS

Although Chinese American immigrant women share beliefs with other minority women in the United States, some culturally related barriers such as alienation due to cultural reasons for not sharing diagnosis with anyone and beliefs about the efficacy of Eastern versus Western medicine may affect adherence to screening and treatment. Facilitators included being told to get the test and getting screened for the sake of the family, whereas erroneous information about the cause of breast cancer such as diet and stress remained. Primary care providers such as advanced practice nurses should take into account culturally driven motivations and barriers to mammography adherence among Chinese American immigrant women. Provider/client interactions should involve more discussion about women's breast cancer risks and screening harms and benefits. Such awareness could open a dialogue around breast cancer that is culturally sensitive and nonthreatening to the patient. Information may need to be tailored to women individually or targeted to subethnic groups rather than using generic messages for all Asian immigrant women.

Going against the tide: increasing incidence of colorectal cancer among Koreans, Filipinos, and South Asians in California, 1988-2007

OBJECTIVE

Colorectal cancer has declined markedly in California for all major racial/ethnic groups, including Asian/Pacific Islanders as a whole. Analyzing cancer data for Asian/Pacific Islanders collectively masks important differences that exist between individual Asian subgroups. This study examines secular, sex-, age-, and socioeconomic-specific trends in colorectal cancer incidence among six Asian subgroups-Chinese, Japanese, Filipino, Korean, Vietnamese, and South Asian-to determine whether these groups experienced a decline in colorectal cancer incidence and to assess possible differences in colorectal cancer incidence trends among these groups.

METHODS

Cases of invasive colorectal cancer diagnosed among Japanese, Chinese, Filipinos, Koreans, Vietnamese, and South Asians between 1988 and 2007 were identified using the California Cancer Registry database. Secular, sex-, age-, and socioeconomic-specific trends in the age-adjusted colorectal cancer incidence rates for each Asian subgroup were examined using joinpoint analysis to estimate the annual percent change (APC).

RESULTS

Among males, Koreans (APC, 3.6 %) were the only group that experienced a significant increase in colorectal cancer incidence. Among females, Koreans (APC, 2.7 %), South Asians (APC, 2.8 %), and Filipinos (APC, 1.6 %) experienced significant increases. Stratification by age at diagnosis revealed that Korean males (APC, 3.4 %) and females (APC, 2.9 %) as well as Filipino females (APC, 1.8 %) aged 50 years and older experienced a significant increase in colorectal cancer incidence. Korean males aged less than 50 years (APC, 3.4 %) also experienced a significant increase. Japanese (APC, -1.2 %) and Chinese (APC, -1.6 %) males aged 50 years and older experienced a significant decrease in colorectal cancer incidence. Stratification by socioeconomic status (SES) revealed that Korean males (APC, 2.5 %) and females (APC, 2.9 %) as well as Filipino females (APC, 2.1 %) in the lowest SES category experienced a significant increase in colorectal cancer incidence. Korean males (APC, 5.2 %) and females (APC, 3.1 %) as well as Filipino males (APC, 1.5 %) in the highest SES category also experienced a significant increase. Japanese males (APC, -2.5 %) and females (APC, -2.0 %) as well as Chinese males (APC, -2.8 %) and females (APC, -2.9 %) in the lowest SES category experienced a significant decrease. Chinese males in the middle (APC, -3.4 %) and highest (APC, -3.5 %) SES categories also experienced significant decreases in colorectal cancer incidence.

CONCLUSIONS

In contrast to the decreasing trends in colorectal cancer incidence reported among all major racial/ethnic groups including Asian/Pacific Islanders, colorectal cancer is actually increasing among some Asian subgroups in California including Korean males and females, as well as South Asian and Filipino females. Furthermore, the colorectal cancer incidence trends for these Asian subgroups differ with respect to age at diagnosis and socioeconomic status. These findings suggest that more efforts need to be made to target these populations with culturally sensitive cancer prevention and screening programs. More research is needed to examine the differences in the colorectal cancer burden among these populations.

Passing through: meanings of survivorship and support among Filipinas with breast cancer

Breast cancer among Filipinas in the United States is a major but largely neglected cancer disparity. In 2004, a community- university partnership resulted in the first Filipina breast cancer support group in the San Francisco Bay Area. Building on this partnership, we explored the social and cultural contexts of Filipinas' experiences with breast cancer to inform development of culturally appropriate and sustainable support services and outreach. We utilized multiple qualitative methods (participant observation, individual and small group in-depth qualitative interviews) to identify meanings of survivorship and support. Interviews and observations revealed the influences of social context and immigration experiences on women's understandings of cancer, what "surviving" cancer means, and what it means to take care of someone with breast cancer (or be taken care of). Our findings highlight the importance of a transnational perspective for the study of immigrant women's experiences of cancer and survivorship.

Invasive breast cancer incidence trends by detailed race/ethnicity and age

Racial/ethnic disparities in breast cancer incidence may contain important evidence for understanding and control of the disease. Monitoring the incidence trends of breast cancer by race/ethnicity allows identification of high risk groups and development of targeted prevention programs. Using population-based cancer registry data from the Los Angeles Cancer Surveillance Program, we examined the invasive female breast cancer incidence trends among the diverse racial/ethnic populations in Los Angeles County, California, from 1972 to 2007. Age-adjusted incidence rates (AAIRs) and age-specific incidence rates (ASIRs) were calculated and examined respectively for non-Hispanic (NH) white, black, Hispanic, Chinese, Filipina, Japanese and Korean women by calendar year and time period. Rising trends of AAIRs were found in all racial/ethnic groups during the 1980s and 1990s. The breast cancer risk increased more substantially in Japanese and Filipinas than in Chinese and Koreans. During 2000-2007, the trends of AAIRs declined significantly among NH white women and slightly in blacks, remained unchanged for Hispanics and continued to rise significantly among all Asian subgroups. The patterns of ASIRs by race/ethnicity changed dramatically over time. By 2000-2007, younger Hispanic women had the lowest breast cancer risk, replacing the Chinese and Koreans who formerly had the lowest risk. Rapidly increasing breast cancer incidence trends among Asian-Americans underline the importance of behavioral and lifestyle changes as a result of acculturation on the development of the disease. The unique trends of breast cancer incidence by race/ethnicity suggest the need for targeted breast cancer control programs for different racial/ethnic populations.

Nativity and papillary thyroid cancer incidence rates among Hispanic women in California

BACKGROUND

Overall, the incidence of papillary thyroid cancer in Hispanic women residing in the United States (US) is similar to that of non-Hispanic white women. However, little is known as to whether rates in Hispanic women vary by nativity, which may influence exposure to important risk factors.

METHODS

Nativity-specific incidence rates among Hispanic women were calculated for papillary thyroid cancer using data from the California Cancer Registry (CCR) for the period 1988-2004. For the 35% of cases for whom birthplace information was not available from the CCR, nativity was statistically imputed based on age at Social Security number issuance. Population estimates were extracted based on US Census data. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were also estimated.

RESULTS

In young (age <55 years) Hispanic women, the incidence of papillary thyroid cancer among US-born women (10.65 per 100,000) was significantly greater than that for foreign-born women (6.67 per 100,000; IRR, 1.60 [95% CI, 1.44-1.77]). The opposite pattern was observed in older women. The age-specific patterns showed marked differences by nativity: among foreign-born women, rates increased slowly until age 70 years, whereas among US-born women, incidence rates peaked during the reproductive years. Incidence rates increased over the study period in all subgroups.

CONCLUSION

Incidence rates of papillary thyroid cancer vary by nativity and age among Hispanic women residing in California. These patterns can provide insight for future etiologic investigations of modifiable risk factors for this increasingly common and understudied cancer.

Lymphoid malignancies in U.S. Asians: incidence rate differences by birthplace and acculturation

BACKGROUND

Malignancies of the lymphoid cells, including non-Hodgkin lymphomas (NHL), HL, and multiple myeloma, occur at much lower rates in Asians than other racial/ethnic groups in the United States. It remains unclear whether these deficits are explained by genetic or environmental factors. To better understand environmental contributions, we examined incidence patterns of lymphoid malignancies among populations characterized by ethnicity, birthplace, and residential neighborhood socioeconomic status (SES) and ethnic enclave status.

METHODS

We obtained data about all Asian patients diagnosed with lymphoid malignancies between 1988 and 2004 from the California Cancer Registry and neighborhood characteristics from U.S. Census data.

RESULTS

Although incidence rates of most lymphoid malignancies were lower among Asian than white populations, only follicular lymphoma (FL), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), and nodular sclerosis (NS) HL rates were statistically significantly lower among foreign-born than U.S.-born Asians with incidence rate ratios ranging from 0.34 to 0.87. Rates of CLL/SLL and NS HL were also lower among Asian women living in ethnic enclaves or lower SES neighborhoods than those living elsewhere.

CONCLUSIONS

These observations support strong roles of environmental factors in the causation of FL, CLL/SLL, and NS HL.

IMPACT

Studying specific lymphoid malignancies in U.S. Asians may provide valuable insight toward understanding their environmental causes.

Breast cancers in U.S. residing Indian-Pakistani versus non-Hispanic White women: comparative analysis of clinical-pathologic features, treatment, and survival

South Asians from India and Pakistan represent one of the fastest growing immigrant populations in the US, yet there are limited data assessing breast cancers for this distinct ethnic sub-group. The aim of this study was to analyze clinical-pathologic, treatment and outcome characteristics of U.S.-residing Indian-Pakistani (IP) versus non-Hispanic white (NHW) female breast cancer patients to assess if any differences/disparities exist. The study cohort consisted of 2,393 IP and 555,832 NHW women (diagnosed 1988-2006) in the SEER database. Differences between the two populations were analyzed using chi-squared and multivariate regression analysis. Age-adjusted incidence, mortality, and relative survival rates were calculated for the two groups. Significant differences in the characteristics of the IP cohort's invasive disease included: younger median age at presentation; larger tumor size; higher stage, higher grade, more involved lymph-nodes, and more hormone receptor negative disease (all P < 0.01). The age-adjusted incidence and breast cancer mortality were lower in IP women. The relative survival at 5 years was statistically significant at 84% for IP versus 89% for NHW women, but was not significantly different on multivariate analysis (P > 0.05). Within each stage (Tis, I, II), there were no disparities in the rate of breast conservation surgery (BCS) or in the percentage of patients receiving adjuvant radiation after BCS for the 2 cohorts. Post-mastectomy radiation was delivered significantly more often in stage I/II IP patients undergoing mastectomy. In conclusion, this analysis suggests that while there appear to be significant differences in the features of breast cancers of US-residing IP women, no disparities were noted in the rates of breast conserving surgery or adjuvant radiation, as seen in some other ethnicities. The more aggressive clinical-pathologic features stage-for-stage in IP women may partially explain the more frequent use of post-mastectomy RT in this patient population. These findings warrant further investigation.

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.

Asian ethnicity and breast cancer subtypes: a study from the California Cancer Registry

The distribution of breast cancer molecular subtypes has been shown to vary by race/ethnicity, highlighting the importance of host factors in breast tumor biology. We undertook the current analysis to determine population-based distributions of breast cancer subtypes among six ethnic Asian groups in California. We defined immunohistochemical (IHC) surrogates for each breast cancer subtype among Chinese, Japanese, Filipina, Korean, Vietnamese, and South Asian patients diagnosed with incident, primary, invasive breast cancer between 2002 and 2007 in the California Cancer Registry as: hormone receptor-positive (HR+)/HER2- [estrogen receptor-positive (ER+) and/or progesterone receptor-positive (PR+), human epidermal growth factor receptor 2-negative (HER2-)], triple-negative (ER-, PR-, and HER2-), and HER2-positive (ER±, PR±, and HER2+). We calculated frequencies of breast cancer subtypes among Asian ethnic groups and evaluated their associations with clinical and demographic factors. Complete IHC data were available for 8,140 Asian women. Compared to non-Hispanic White women, Korean [odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.5-2.2], Filipina (OR = 1.3, 95% CI = 1.2-1.5), Vietnamese (OR = 1.3, 95% CI = 1.1-1.6), and Chinese (OR = 1.1, 95% CI = 1.0-1.3) women had a significantly increased risk of being diagnosed with HER2-positive breast cancer subtypes after adjusting for age, stage, grade, socioeconomic status, histology, diagnosis year, nativity, and hospital ownership status. We report a significant ethnic disparity in HER2-positive breast cancer in a large population-based cohort enriched for Asian-Americans. Given the poor prognosis and high treatment costs of HER2-positive breast cancer, our results have implications for healthcare resource utilization, cancer biology, and clinical care.

Hidden breast cancer disparities in Asian women: disaggregating incidence rates by ethnicity and migrant status

OBJECTIVES

We estimated trends in breast cancer incidence rates for specific Asian populations in California to determine if disparities exist by immigrant status and age.

METHODS

To calculate rates by ethnicity and immigrant status, we obtained data for 1998 through 2004 cancer diagnoses from the California Cancer Registry and imputed immigrant status from Social Security Numbers for the 26% of cases with missing birthplace information. Population estimates were obtained from the 1990 and 2000 US Censuses.

RESULTS

Breast cancer rates were higher among US- than among foreign-born Chinese (incidence rate ratio [IRR] = 1.84; 95% confidence interval [CI] = 1.72, 1.96) and Filipina women (IRR = 1.32; 95% CI = 1.20, 1.44), but similar between US- and foreign-born Japanese women. US-born Chinese and Filipina women who were younger than 55 years had higher rates than did White women of the same age. Rates increased over time in most groups, as high as 4% per year among foreign-born Korean and US-born Filipina women. From 2000-2004, the rate among US-born Filipina women exceeded that of White women.

CONCLUSIONS

These findings challenge the notion that breast cancer rates are uniformly low across Asians and therefore suggest a need for increased awareness, targeted cancer control, and research to better understand underlying factors.

Comparison of disability rates among older adults in aggregated and separate Asian American/Pacific Islander subpopulations

OBJECTIVES

We assessed the prevalence and adjusted odds of 4 types of disability among 7 groups of older Asian American/Pacific Islander (AAPI) subpopulations, both separately and aggregated, compared with non-Hispanic Whites.

METHODS

Data were from the nationally representative 2006 American Community Survey, which included institutionalized and community-dwelling Hawaiian/Pacific Islander (n = 524), Vietnamese (n = 2357), Korean (n = 2082), Japanese (n = 3230), Filipino (n = 5109), Asian Indian (n = 2942), Chinese (n = 6034), and non-Hispanic White (n = 641 177) individuals aged 55 years and older. The weighted prevalence, population estimates, and odds ratios of 4 types of disability (functional limitations, limitations in activities of daily living, cognitive problems, and blindness or deafness) were reported for each group.

RESULTS

Disability rates in older adults varied more among AAPI subpopulations than between non-Hispanic Whites and the aggregated Asian group. Asian older adults had, on average, better disability outcomes than did non-Hispanic Whites.

CONCLUSIONS

This study provides the strongest evidence to date that exclusion of institutionalized older adults minimizes disparities in disabilities between Asians and Whites. The aggregation of Asians into one group obscures substantial subgroup variability and fails to identify the most vulnerable groups (e.g., Hawaiian/Pacific Islanders and Vietnamese).

Disparities in breast cancer survival among Asian women by ethnicity and immigrant status: a population-based study

OBJECTIVES

We investigated heterogeneity in ethnic composition and immigrant status among US Asians as an explanation for disparities in breast cancer survival.

METHODS

We enhanced data from the California Cancer Registry and the Surveillance, Epidemiology, and End Results program through linkage and imputation to examine the effect of immigrant status, neighborhood socioeconomic status, and ethnic enclave on mortality among Chinese, Japanese, Filipino, Korean, South Asian, and Vietnamese women diagnosed with breast cancer from 1988 to 2005 and followed through 2007.

RESULTS

US-born women had similar mortality rates in all Asian ethnic groups except the Vietnamese, who had lower mortality risk (hazard ratio [HR] = 0.3; 95% confidence interval [CI] = 0.1, 0.9). Except for Japanese women, all foreign-born women had higher mortality than did US-born Japanese, the reference group. HRs ranged from 1.4 (95% CI = 1.2, 1.7) among Koreans to 1.8 (95% CI = 1.5, 2.2) among South Asians and Vietnamese. Little of this variation was explained by differences in disease characteristics.

CONCLUSIONS

Survival after breast cancer is poorer among foreign- than US-born Asians. Research on underlying factors is needed, along with increased awareness and targeted cancer control.

Breast cancer screening among Vietnamese Americans: a randomized controlled trial of lay health worker outreach

BACKGROUND

Vietnamese-American women underutilize breast cancer screening.

DESIGN

An RCT was conducted comparing the effect of lay health workers (LHWs) and media education (ME) to ME alone on breast cancer screening among these women.

SETTING/PARTICIPANTS

Conducted in California from 2004 to 2007, the study included 1100 Vietnamese-American women aged > or = 40 years who were recruited through LHW social networks. Data were analyzed from 2007 to 2009.

INTERVENTION

Both groups received targeted ME. The intervention group received two LHW educational sessions and two telephone calls.

MAIN OUTCOME MEASURES

Change in self-reported receipt of mammography ever, mammography within 2 years, clinical breast examination (CBE) ever, or CBE within 2 years.

RESULTS

The LHW+ME group increased receipt of mammography ever and mammography in the past 2 years (84.1% to 91.6% and 64.7% to 82.1%, p<0.001) while the ME group did not. Both ME (73.1% to 79.0%, p<0.001) and LHW+ME (68.1% to 85.5%, p<0.001) groups increased receipt of CBE ever, but the LHW+ME group had a significantly greater increase. The results were similar for CBE within 2 years. In multivariate analyses, LHW+ME was significantly more effective than ME for all four outcomes, with ORs of 3.62 (95% CI=1.35, 9.76) for mammography ever; 3.14 (95% CI=1.98, 5.01) for mammography within 2 years; 2.94 (95% CI=1.63, 5.30) for CBE ever; and 3.04 (95% CI=2.11, 4.37) for CBE within 2 years.

CONCLUSIONS

Lay health workers increased breast cancer screening among Vietnamese-American women.Future research should focus on how LHWs work and whether LHW outreach can be disseminated to other ethnic groups [corrected].

Cervical cancer incidence, mortality, and survival among Asian subgroups in California, 1990-2004

BACKGROUND

Aggregated cancer statistics for Asians mask important differences in cancer burden among Asian subgroups. The purpose of this study was to describe the relative patterns of cervical cancer incidence, mortality, and survival among Chinese, Filipino, Japanese, Korean, South Asian, and Vietnamese women in California, using data from the California Cancer Registry.

METHODS

All cervical cancer cases diagnosed among the 6 subgroups and non-Hispanic whites (NHW) from 1990 to 2004 were identified and used to calculate incidence and mortality rates and trends. The Kaplan-Meier method was used to calculate 5- and 10-year survival probabilities by subgroup, and Cox proportional hazards methodology was used to calculate survival differences adjusted for race and ethnicity, age, stage at diagnosis, socioeconomic status, and treatment factors.

RESULTS

Vietnamese and Korean women experienced greater cervical cancer incidence and mortality than NHW women, whereas rates among Chinese, Japanese, and South Asians were comparable or lower. Five-year unadjusted survival probabilities were greatest for South Asians (86%) and Koreans (86%), followed by Vietnamese (82%), Chinese (79%), and Filipinos (79%), as compared with NHW (78%) and Japanese (72%). The adjusted risk of cervical cancer death was significantly lower for South Asians, Koreans, Vietnamese, and Filipinos than for NHW women, but not for Chinese and Japanese.

CONCLUSIONS

Cervical cancer incidence rates vary substantially across the major Asian subgroups. Despite higher incidence and mortality rates compared with NHW women, Vietnamese, Koreans, and Filipinos have better survival outcomes. Further studies are needed to examine the factors behind these survival differences.

Incidence of lymphoid neoplasms by subtype among six Asian ethnic groups in the United States, 1996-2004

OBJECTIVES

To establish baseline data for lymphoid neoplasm incidence by subtype for six Asian-American ethnic groups.

METHODS

Incident rates were estimated by age and sex for six Asian ethnic groups--Asian Indian/Pakistani, Chinese, Filipino, Japanese, Korean, Vietnamese--in five United States cancer registry areas during 1996-2004. For comparison, rates for non-Hispanic Whites were also estimated.

RESULTS

During 1996-2004, Filipinos had the highest (24.0) and Koreans had the lowest incidence (12.7) of total lymphoid neoplasms. By subtype, Vietnamese and Filipinos had the highest incidence for diffuse large B-cell lymphoma (DLBCL) (8.0 and 7.2); Japanese had the highest incidence of follicular lymphoma (2.3). Although a general male predominance of lymphoid neoplasms was observed, this pattern varied by lymphoid neoplasm subtype. Whites generally had higher rates than all Asian ethnic groups for all lymphoid neoplasms and most lymphoma subtypes, although the magnitude of the difference varied by both ethnicity and lymphoma subtype.

CONCLUSIONS

The observed variations in incidence patterns among Asian ethnic groups in the United States suggest that it may be fruitful to pursue studies that compare Asian populations for postulated environmental and genetic risk factors.

Recent breast cancer trends among Asian/Pacific Islander, Hispanic, and African-American women in the US: changes by tumor subtype

BACKGROUND

Recently, unprecedented drops in breast cancer incidence have been reported for populations of mostly White European descent. Incidence patterns in non-White racial/ethnic groups are less described. Therefore, we examined population-based breast cancer incidence trends separately for US Asian/Pacific Islander, Hispanic, African-American, and non-Hispanic White women by etiologically relevant tumor subtype characteristics, including hormone receptor status, histology, size, and in situ behavior.

METHODS

We obtained breast cancer data from 13 Surveillance, Epidemiology, and End Results (SEER) cancer registries to calculate age-adjusted incidence rates and trends, stratified by race/ethnicity and tumor subtype for the period 1992-2004. Detailed analyses were limited to women 50 years old or older. Joinpoint regression was used to assess incidence trends by annual quarter of diagnosis.

RESULTS

Between 2001 and 2004, incidence rates of invasive breast cancer in women 50 years old or older declined appreciably among Asians/Pacific Islanders (-8.5%) and Hispanics (-2.9%) and were stable in African-Americans (+0.5%), reductions substantially lower than those observed among non-Hispanic Whites (-14.3%). In Asian/Pacific Islander women, perceptible but statistically nonsignificant decreases were observed for hormone receptor-positive, lobular, and small tumors only. Rates of hormone receptor-negative tumors increased among African-Americans (26.1%) and Hispanics (26.9%) during 2001-2004. Incidence trends in most groups, except African-American women, peaked between 1999 and mid-2002. Rates of in situ cancer remained stable in all groups.

CONCLUSION

Recently reported reductions in breast cancer incidence varied considerably by race/ethnicity. These patterns are consistent with documented racial/ethnic differences in the prevalence and discontinuation of hormone therapy (HT) after July 2002 but do not correspond as well to patterns of mammography use in these groups. The data presented in this analysis provide further evidence that population-level HT use is a major influence on population-level rates of particular breast cancer subtypes, especially receptor-positive tumors.

Exploring the underlying hormonal mechanisms of prenatal risk factors for breast cancer: a review and commentary

Prenatal factors have been hypothesized to influence subsequent breast cancer development. Directly evaluating the associations of in utero exposures with risk, however, presents several methodologic and theoretical challenges, including the long induction period between exposure and disease and the lack of certainty regarding the critical timing of exposure. Indirect evaluation of these associations has been achieved by use of proxies such as gestational and neonatal characteristics. Evidence suggests that preeclampsia is associated with a reduced breast cancer risk, whereas high birth weight and dizygotic twinning seem associated with an increased risk. Asians born in Asia have substantially lower breast cancer risks than women born in the West. Although data thus far are few, what exists is not consistent with a unifying hypothesis for a particular biological exposure (such as estrogens or androgens) during pregnancy as mediating the observed associations between pregnancy factors and breast cancer risk. This suggests that additional studies of prenatal factors should seek to broaden the range of hormones, growth, and other endocrine factors that are evaluated in utero. Once candidate biomarkers are identified, assessing them with respect to breast cancer and with intermediate end points in carcinogenesis should be a priority. In addition, investigations should explore the possibility that in utero exposures may not act directly on the breast, but may alter other physiologic pathways such as hormone metabolism that have their effect on risk later in life.

Cancer incidence rates among South Asians in four geographic regions: India, Singapore, UK and US

BACKGROUND

Data are limited regarding cancer incidence among Indians residing in different geographic regions around the world. Examining such rates may provide us with insights into future aetiological research possibilities as well as screening and prevention.

METHODS

Incidence rates for all cancers combined and 19 specific cancers were obtained for India from Globocan 2002, for Indians in Singapore from Cancer Incidence in Five Continents (VIII), and from national data sources for South Asians (SA) in the United Kingdom (UK) and for Asian Indians/Pakistanis (AIP) and whites in the United States (US).

RESULTS

We observed the lowest total cancer incidence rates in India (111 and 116 per 100,000 among males and females, respectively, age-standardized to the 1960 world population) and the highest among US whites (362 and 296). Cancer incidence rates among Indians residing outside of India were: intermediate Singapore (102 and 132), UK (173 and 179) and US ranges 152-176 and 142-164. A similar pattern was observed for cancers of the colorectum, prostate, thyroid, pancreas, lung, breast and non-Hodgkin lymphoma. In contrast, rates for cancers of the oral cavity, oesophagus, larynx and cervix uteri were highest in India. Although little geographic variability was apparent for stomach cancer incidence, Indians in Singapore had the highest rates compared with any other region. The UK SA and the US AIP appear with adopt the cancer patterns of their host country.

CONCLUSION

Variations in environmental exposures such as tobacco use, diet and infection, as well as better health care access and knowledge may explain some of the observed incidence differences.