How relevant is breast cancer screening in the Asia/Pacific region?

Breast Cancer in Asia: Incidence, Mortality, Early Detection, Mammography Programs, and Risk-Based Screening Initiatives

Simple Summary

Nearly all breast cancer patients survive for more than five years when the tumor is found early and in the localized stage. Regular clinical breast examinations, mammograms, and monthly self-exams of the breasts all contribute to early detection. However, late-stage breast cancers are common in many Asian countries. Low-income countries suffer from a lack of resources for breast cancer screening. High-income countries, on the other hand, are not benefiting fully from national breast screening programs due to an underutilization of the preventive healthcare services available. Existing reviews on Asian breast cancers are heavily focused on risk factors. The question of whether we should adopt or adapt the knowledge generated from non-Asian breast cancers would benefit from an extension into screening guidelines. In addition, several Asian countries are piloting studies that move away from the age-based screening paradigm.

Abstract

Close to half (45.4%) of the 2.3 million breast cancers (BC) diagnosed in 2020 were from Asia. While the burden of breast cancer has been examined at the level of broad geographic regions, literature on more in-depth coverage of the individual countries and subregions of the Asian continent is lacking. This narrative review examines the breast cancer burden in 47 Asian countries. Breast cancer screening guidelines and risk-based screening initiatives are discussed.

Establishment of a deep-learning system to diagnose BI-RADS4a or higher using breast ultrasound for clinical application

Although the categorization of ultrasound using the Breast Imaging Reporting and Data System (BI‐RADS) has become widespread worldwide, the problem of inter‐observer variability remains. To maintain uniformity in diagnostic accuracy, we have developed a system in which artificial intelligence (AI) can distinguish whether a static image obtained using a breast ultrasound represents BI‐RADS3 or lower or BI‐RADS4a or higher to determine the medical management that should be performed on a patient whose breast ultrasound shows abnormalities. To establish and validate the AI system, a training dataset consisting of 4028 images containing 5014 lesions and a test dataset consisting of 3166 images containing 3656 lesions were collected and annotated. We selected a setting that maximized the area under the curve (AUC) and minimized the difference in sensitivity and specificity by adjusting the internal parameters of the AI system, achieving an AUC, sensitivity, and specificity of 0.95, 91.2%, and 90.7%, respectively. Furthermore, based on 30 images extracted from the test data, the diagnostic accuracy of 20 clinicians and the AI system was compared, and the AI system was found to be significantly superior to the clinicians (McNemar test, p < 0.001). Although deep‐learning methods to categorize benign and malignant tumors using breast ultrasound have been extensively reported, our work represents the first attempt to establish an AI system to classify BI‐RADS3 or lower and BI‐RADS4a or higher successfully, providing important implications for clinical actions. These results suggest that the AI diagnostic system is sufficient to proceed to the next stage of clinical application.

Pregnancy-associated plasma protein-A (PAPPA) promotes breast cancer progression

Breast cancer is the most common malignancy in females and poses a significant health threat to women. Pregnancy-associated plasma protein-A (PAPPA) is highly expressed in pregnancy-associated breast cancer (PABC) tissues. In this study, we investigated the functional role of PAPPA in regulating the malignant phenotype of breast cancer. We first examined the expression level of PAPPA in PABC tissue and breast cancer cell lines using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot. Next, the functional role of PAPPA in breast cancer cells was validated by overexpression and knockdown experiments. Cell counting kit-8 (CCK-8) proliferation assay, 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, wound healing and transwell invasion assay were used to examine cell proliferation, migration, and invasion ability. We further identified the microRNA target regulating PAPPA and studied its functional role. Finally, we examined the impact of PAPPA on the tumorigenesis and metastasis of breast cancer in mice model. Our study revealed that PAPPA was upregulated in PABC tissues and breast cancer cells. Overexpression of PAPPA promoted cell proliferation, motility, invasion, and epithelial-mesenchymal transition (EMT). We further identified miR-497-5p as a negative regulator of PAPPA, which suppressed cell proliferation, migration, invasion, and EMT in breast cancer cells. We also validated the oncogenic role of PAPPA in the mouse xenograft model. Collectively, our study suggests that PAPPA is an oncogenic protein highly expressed in PABC tissues and promotes breast cancer progression, which could serve as a novel therapeutic target for breast cancer.

Atypical Ductal Hyperplasia of the Breast on Core Needle Biopsy: Risk of Malignant Upgrade On Surgical Excision

Purpose

This study identified factors predicting malignant upgrade for atypical ductal hyperplasia (ADH) diagnosed on core-needle biopsy (CNB) and developed a nomogram to facilitate evidence-based decision making.

Methods

This retrospective analysis included women diagnosed with ADH at the National Cancer Centre Singapore (NCCS) in 2010–2015. Cox proportional hazards regression was used to identify clinical, radiological, and histological factors associated with malignant upgrade. A nomogram was constructed using variables with the strongest associations in multivariate analysis. Multivariable logistic regression coefficients were used to estimate the predicted probability of upgrade for each factor combination.

Results

Between 2010 and 2015, 238,122 women underwent mammographic screening under the National Breast Cancer Screening Program. Among 29,564 women recalled, 5,971 CNBs were performed. Of these, 2,876 underwent CNBs at NCCS, with 88 patients (90 lesions) diagnosed with ADH and 26 lesions upgraded to breast malignancy on excision biopsy. In univariate analysis, factors associated with malignant upgrade were the presence of a mass on ultrasound (p = 0.018) or mammography (p = 0.026), microcalcifications (p = 0.047), diffuse microcalcification distribution (p = 0.034), mammographic parenchymal density (p = 0.008). and ≥ 3 separate ADH foci found on biopsy (p = 0.024). Mammographic parenchymal density (hazard ratio [HR], 0.04; 95% confidence interval [CI], 0.005–0.35; p = 0.014), presence of a mass on ultrasound (HR, 10.50; 95% CI, 9.21–25.2; p = 0.010), and number of ADH foci (HR, 1.877; 95% CI, 1.831–1.920; p = 0.002) remained significant in multivariate analysis and were included in the nomogram.

Conclusion

Our model provided good discrimination of breast cancer risk prediction (C-statistic of 0.81; 95% CI, 0.74–0.88) and selected for a subset of women at low risk (2.1%) of malignant upgrade, who may avoid surgical excision following a CNB diagnosis of ADH.

Breast cancer in Mongolia: an increasingly important health policy issue

Breast cancer is a leading cause of cancer-related death for women in both developed and developing countries. The incidence and mortality of breast cancer in Mongolia, while low compared with other counties, has been increasing on an annual basis. In addition, in Mongolia, approximately 90% of the patients are diagnosed at a late stage, resulting in high mortality, with the majority of individuals diagnosed with breast cancer dying within 5 years of diagnosis. Breast cancer screening plays an important role in reducing mortality in Western countries and has been adopted by a number of Asian countries; however, no such approach exists in Mongolia. In a country of limited resources, implementation of expensive health strategies such as screening requires effective allocations of resources and the identification of the most effective imaging methods. This requirement relies on recent accurate data; however, at this time, there is a paucity of information around breast cancer in Mongolia. Until data around features of the disease are available, effective strategies to diagnose breast cancer that recognize the economic climate in Mongolia cannot be implemented and the impact of breast cancer is likely to increase.

Breast Density and Risk of Breast Cancer in Asian Women: A Meta-analysis of Observational Studies

OBJECTIVES

The established theory that breast density is an independent predictor of breast cancer risk is based on studies targeting white women in the West. More Asian women than Western women have dense breasts, but the incidence of breast cancer is lower among Asian women. This meta-analysis investigated the association between breast density in mammography and breast cancer risk in Asian women.

METHODS

PubMed and Scopus were searched, and the final date of publication was set as December 31, 2015. The effect size in each article was calculated using the interval-collapse method. Summary effect sizes (sESs) and 95% confidence intervals (CIs) were calculated by conducting a meta-analysis applying a random effect model. To investigate the dose-response relationship, random effect dose-response meta-regression (RE-DRMR) was conducted.

RESULTS

Six analytical epidemiology studies in total were selected, including one cohort study and five case-control studies. A total of 17 datasets were constructed by type of breast density index and menopausal status. In analyzing the subgroups of premenopausal vs. postmenopausal women, the percent density (PD) index was confirmed to be associated with a significantly elevated risk for breast cancer (sES, 2.21; 95% CI, 1.52 to 3.21; I²=50.0%). The RE-DRMR results showed that the risk of breast cancer increased 1.73 times for each 25% increase in PD in postmenopausal women (95% CI, 1.20 to 2.47).

CONCLUSIONS

In Asian women, breast cancer risk increased with breast density measured using the PD index, regardless of menopausal status. We propose the further development of a breast cancer risk prediction model based on the application of PD in Asian women.

The need for supplemental breast cancer screening modalities: a perspective of population-based breast cancer screening programs in Japan

PURPOSE

This article discusses possible supplemental breast cancer screening modalities for younger women with dense breasts from a perspective of population-based breast cancer screening program in Japan.

CONCLUSION

Supplemental breast cancer screening modalities have been proposed to increase the sensitivity and detection rates of early stage breast cancer in women with dense breasts; however, there are no global guidelines that recommend the use of supplemental breast cancer screening modalities in such women. Also, no criterion standard exists for breast density assessment. Based on the current situation of breast imaging in Japan, the possible supplemental breast cancer screening modalities are ultrasonography, digital breast tomosynthesis, and breast magnetic resonance imaging. An appropriate population-based breast cancer screening program based on the balance between cost and benefit should be a high priority. Further research based on evidence-based medicine is encouraged. It is very important that the ethnicity, workforce, workflow, and resources for breast cancer screening in each country should be considered when considering supplemental breast cancer screening modalities for women with dense breasts.

Female breast cancer incidence among Asian and Western populations: more similar than expected

BACKGROUND

Previous reports suggested that female breast cancer is associated with earlier ages at onset among Asian than Western populations. However, most studies utilized cross-sectional analyses that may be confounded by calendar-period and/or birth cohort effects. We, therefore, considered a longitudinal (forward-looking) approach adjusted for calendar-period changes and conditioned upon birth cohort.

METHODS

Invasive female breast cancer data (1988-2009) were obtained from cancer registries in China, Hong Kong, South Korea, Taiwan, Singapore, and the United States. Age-period-cohort models were used to extrapolate longitudinal age-specific incidence rates for the 1920, 1944, and 1970 birth cohorts.

RESULTS

Cross-sectional age-specific incidence rates rose continuously until age 80 years among US white women, but plateaued or decreased after age 50 years among Asian women. In contrast, longitudinal age-specific rates were proportional (similar) among all Asian countries and the United States with incidence rates rising continuously until age 80 years. The extrapolated estimates for the most recent cohorts in some Asian countries actually showed later ages at onset than in the United States. Additionally, over successive birth cohorts, the incidence rate ratios (IRRs) for the longitudinal curves converged (narrowed) between Asian and US white women.

CONCLUSIONS

Similar longitudinal age-specific incidence rates along with converging IRRs indicate that the age effects for invasive breast cancer are more similar among Asian and Western populations than might be expected from a solely cross-sectional analysis. Indeed, the Asian breast cancer rates in recent generations are even surpassing the historically high rates in the United States, highlighting an urgent need for efficient prevention and treatment strategies among Asian populations.

Rates of change to a positive result in subsequent screening mammography in Korean women: a retrospective observational study

OBJECTIVES

This retrospective cohort study aimed at calculating some parameters of changes in the findings of the subsequent screening mammography (SSM) in female Korean volunteers.

METHODS

The study included screenees aged 30 to 79 years who underwent SSM voluntarily after testing negative in the baseline screenings performed between January 2007 and December 2011. A change to a positive result was defined as category 4 or 5 by using the American College of Radiology Breast Imaging Reporting and Data System. The proportion of results that had changed to positive (CP, %) was calculated by dividing the number of cases with results that were positive in the SSM by the total number of study participants. The rate of results that had changed to positive (CR, cases per 100 000 screenee-months) was calculated by dividing the number of cases with results that were positive in the SSM by the total number of months of the follow-up period.

RESULTS

The overall CP and CR in all age groups (n=77 908) were 2.26% and 93.94 cases per 100 000 screenee-months, respectively. The median CP interval in the subjects who had positive SSM results was 30 to 36 months, while that in the age group of 30 to 39 years was shorter.

CONCLUSIONS

Different screening intervals should be considered among women aged between 30 and 59 years. In addition, a strategy for a screening program should be developed for the age group of 30 to 39 years, in particular.

Improving breast cancer detection using ultrasonography in asymptomatic women with non-fatty breast density

BACKGROUND

Mammography (MX) is a reliable modality for detection of breast cancer in asymptomatic women. Use of additional whole breast ultrasonography (US) for breast cancer screening is widely recognized, in particular in women with dense breast parenchyma.

PURPOSE

To determine the subgroup of women, according to breast density and age, who receive most benefit from US following MX for detection of breast cancer in an asymptomatic condition.

MATERIAL AND METHODS

The study was conducted in asymptomatic women who had non-fatty breast parenchyma using MX and US during January 2006 and December 2007. Mammographic breast density was classified as recommended by ACR BI-RADS lexicon. Non-fatty breast referred to D2, D3, and D4. US was performed by the same radiologists who interpreted MX with a handheld machine during the same visit. Data on demographics, cancer detection rate (CDR), and incremental cancer detection rate (ICDR) were analyzed using 95% confident interval (CI).

RESULTS

Of 14,483 breast cancer screenings in women who had non-fatty breast density, 115 cancers were documented. The mean age of cancer patients was 49.6 years. Of 115 cancers, 105 were evidenced on images (31 with MX alone, 19 with US alone, and 55 with both MX and US). Overall CDR was 7.9 per 1000 examination (95% CI, 6.5-9.5). CDR for MX only (MX-CDR) was 6.5 per 1000 examinations (95% CI, 5.2-7.9). Additional US could significantly improve CDR (P < 0.001; 95% CI, 0.9-2.2); US-ICDR was 1.4 per 1000 examinations. According to age group, the group of 40-59 years had statistically significant improvement of ICDR (P < 0.001). The ICDR was highest in D4 breast density (D4) (US-ICDR = 2.5 per 1000 examinations).

CONCLUSION

Use of US adjunct to MX for detection of breast cancer in asymptomatic non-fatty, average-risk women for detection of breast cancer is a promising diagnostic procedure. A significant benefit was documented, in particular, in women aged 40-59 years old, and in women with D4 breast density.

Incidence and mortality of female breast cancer in the Asia-Pacific region

OBJECTIVE

To provide an overview of the incidence and mortality of female breast cancer for countries in the Asia-Pacific region.

METHODS

Statistical information about breast cancer was obtained from publicly available cancer registry and mortality databases (such as GLOBOCAN), and supplemented with data requested from individual cancer registries. Rates were directly age-standardised to the Segi World Standard population and trends were analysed using joinpoint models.

RESULTS

Breast cancer was the most common type of cancer among females in the region, accounting for 18% of all cases in 2012, and was the fourth most common cause of cancer-related deaths (9%). Although incidence rates remain much higher in New Zealand and Australia, rapid rises in recent years were observed in several Asian countries. Large increases in breast cancer mortality rates also occurred in many areas, particularly Malaysia and Thailand, in contrast to stabilising trends in Hong Kong and Singapore, while decreases have been recorded in Australia and New Zealand. Mortality trends tended to be more favourable for women aged under 50 compared to those who were 50 years or older.

CONCLUSION

It is anticipated that incidence rates of breast cancer in developing countries throughout the Asia-Pacific region will continue to increase. Early detection and access to optimal treatment are the keys to reducing breast cancer-related mortality, but cultural and economic obstacles persist. Consequently, the challenge is to customise breast cancer control initiatives to the particular needs of each country to ensure the best possible outcomes.

Survival rate of breast cancer patients in Malaysia: a population-based study

Breast cancer is the most common cancer among Malaysian women. Other than hospital-based results, there are no documented population-based survival rates of Malaysian women for breast cancers. This population- based retrospective cohort study was therefore conducted. Data were obtained from Health Informatics Centre, Ministry of Health Malaysia, National Cancer Registry and National Registration Department for the period from 1st Jan 2000 to 31st December 2005. Cases were captured by ICD-10 and linked to death certificates to identify the status. Only complete data were analysed. Survival time was calculated from the estimated date of diagnosis to the date of death or date of loss to follow-up. Observed survival rates were estimated by Kaplan- Meier method using SPSS Statistical Software version 17. A total of 10,230 complete data sets were analysed. The mean age at diagnosis was 50.6 years old. The overall 5-year survival rate was 49% with median survival time of 68.1 months. Indian women had a higher survival rate of 54% compared to Chinese women (49%) and Malays (45%). The overall 5-year survival rate of breast cancer patient among Malaysian women was still low for the cohort of 2000 to 2005 as compared to survival rates in developed nations. Therefore, it is necessary to enhance the strategies for early detection and intervention.

Differences in age-standardized mortality rates for avoidable deaths based on urbanization levels in Taiwan, 1971-2008

The World is undergoing rapid urbanization, with 70% of the World population expected to live in urban areas by 2050. Nevertheless, nationally representative analysis of the health differences in the leading causes of avoidable mortality disaggregated by urbanization level is lacking. We undertake a study of temporal trends in mortality rates for deaths considered avoidable by the Concerted Action of the European Community on Avoidable Mortality for four different levels of urbanization in Taiwan between 1971 and 2008. We find that for virtually all causes of death, age-standardized mortality rates (ASMRs) were lower in more urbanized than less urbanized areas, either throughout the study period, or by the end of the period despite higher rates in urbanized areas initially. Only breast cancer had consistently higher AMSRs in more urbanized areas throughout the 38-year period. Further, only breast cancer, lung cancer, and ischemic heart disease witnessed an increase in ASMRs in one or more urbanization categories. More urbanized areas in Taiwan appear to enjoy better indicators of health outcomes in terms of mortality rates than less urbanized areas. Access to and the availability of rich healthcare resources in urban areas may have contributed to this positive result.

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.

Breast cancer research in Asia: adopt or adapt Western knowledge?

The incidence and mortality of breast cancer continues to rise rapidly in Asian countries. However, most of our current knowledge on breast cancer has been generated in Western populations. As the socio-economic profile, life style and culture of Asian and Western women are substantially different, and genetic backgrounds vary to some extent, we need to answer the question on whether to 'adopt' or 'adapt' Western knowledge before applying it in the Asian setting. It is generally accepted that breast cancer risk factors, which have mainly been studied in Western populations are similar worldwide. However, the presence of gene-environment or gene-gene interactions may alter their importance as causal factors across populations. Diagnostic and prognostic study findings, including breast cancer prediction rules, are increasingly shown to be 'setting specific' and must therefore be validated in Asian women before implementing them in clinical care in Asia. Interventional research findings from Caucasian patients may not be applicable in patients in Asia due to differences in tumour biology/profiles, metabolism of drugs and also health beliefs which can influence treatment acceptance and adherence. While breast cancer research in Asia is warranted in all domains of medical research, it is felt that for Asian breast cancer patients, needs are highest for diagnostic and prognostic studies. International clinical trials meanwhile need to include breast cancer patients from various Asian settings to provide an insight into the effectiveness of new treatment modalities in this part of the world.

Knowledge, attitude, and behavior among Saudis toward cancer preventive practice

Objective:

To examine self-reported knowledge, attitude, and preventive practices on cancer among Saudis.

Materials and Methods:

Data was collected from Saudis aged 15 years or more, who attended one of the randomly selected 20 Primary Health Centers (PHC) or the four major private hospitals located in the Riyadh region, either as patients or their escorts. The association between the variables was evaluated by the Chi square test.

Results:

The study population consisted of 618 males and 719 females. Among the female respondents 23.1% reported that they practiced breast self-examination (BSE); 14.2 and 8.1%, respectively, had clinical breast examination (CBE) and mammography. However, 10.0 and 16.1% of the females, aged 40 years and older, reported having had mammograms and CBE, respectively. The BSE performers were more educated, knew someone with cancer, and had heard of the cancer warning signal. Both educational level and ‘heard of cancer warning signal’ were significantly related to CBE. Cancer information was received from television / radio by 65.1% and from the physician by 29.4%. Even though 69.4% believed that cancer could be detected early, a vast majority (95.8%) felt early detection of cancer was extremely desirable and 55.1% said their participation was definite in any screening program. A majority of the respondents (92.6%) insisted on the need for physician recommendation to participate and 78.1% expected that any such program should be conducted in the existing hospitals / clinics.

Conclusion:

Culturally sensitive health education messages should be tailored to fulfill the knowledge gap among all population strata. Saudis will benefit from partnerships between public health educators and media to speed up the dissemination of cancer information.

Breast cancer stage at diagnosis and area-based socioeconomic status: a multicenter 10-year retrospective clinical epidemiological study in China

Background

Although socioeconomic status (SES) has been focused on as a key determinant of cancer stage at diagosis in western countries, there has been no systemic study on the relationship of SES and breast cancer stage at diagnosis in China.

Methods

The medical charts of 4,211 eligible breast cancer patients from 7 areas across China who were diagnosed between 1999 and 2008 were reviewed. Four area-based socioeconomic indicators were used to calculate area-based SES by cluster analysis. The associations between area-based SES and stage at diagnosis were analyzed by trend chi-square tests. Binary logistic regression was performed to estimate odds ratios for individual demographic characteristics' effects on cancer stages, stratified by area-based SES.

Results

The individual demographic and pathologic characteristics of breast cancer cases were significantly different among the seven areas studied. More breast cancer cases in low SES areas (25.5%) were diagnosed later (stages III & IV) than those in high (20.4%) or highest (14.8%) SES areas (χ² for trend = 80.79, P < 0.001). When area-based SES is controlled for, in high SES areas, cases with less education were more likely to be diagnosed at later stages compared with more educated cases. In low SES areas, working women appeared to be diagnosed at earlier breast cancer stages than were homemakers (OR: 0.18-0.26).

Conclusions

In China, women in low SES areas are more likely to be diagnosed at later breast cancer stages than those in high SES areas.

Workplace-based breast cancer screening intervention in china

BACKGROUND

Breast cancer continues to be the primary cause of death among East and Southeast Asian women. Although China, the most populous country in the world, is experiencing unprecedented economic growth, its health care system has yet to benefit from the current economic prosperity. Indeed, studies have shown a consistent increase in breast cancer rates among Chinese women over the past two decades in the absence of breast cancer screening guidelines.

METHODS

The primary objective of this study was to examine the impact of a workplace intervention on increasing breast cancer screening rates. The study was implemented at eight worksites in Nanjing, four of which were assigned to the intervention group (n = 232) and four to the control group (n = 221). The intervention group received breast cancer education and screening navigation. The control group was provided with general cancer education and received a delayed intervention after completion of the study. Study measures were completed at pre- and postprogram and at 6-month follow-up to assess uptake of mammography.

RESULTS

Baseline mammography use was low among both intervention and control groups. However, exposure to the workplace intervention dramatically increased the uptake of mammography from 10.3% at baseline to 72.6% at 6-month follow-up in the intervention group (P < 0.001).

CONCLUSIONS

Findings provide preliminary evidence that the implementation of a comprehensive workplace breast cancer screening intervention program in China can lead to increased uptake of mammography. These data may help facilitate the development of theory-based workplace cancer prevention programs and screening guidelines in China.

IMPACT

A workplace-based multifaceted intervention could have a strong impact in breast cancer prevention and early detection among women in China.

Global breast cancer: the lessons to bring home

Breast cancer is the most common cancer affecting women globally. This paper discusses the current progress in breast cancer in Western countries and focuses on important differences of this disease in low- and middle-income countries (LMCs). It introduces several arguments for applying caution before globalizing some of the US-adopted practices in the screening and management of the disease. Finally, it suggests that studies of breast cancer in LMCs might offer important insights for a more effective management of the problem both in developing as well as developed countries.

Genetic and clinical predictors for breast cancer risk assessment and stratification among Chinese women

BACKGROUND

Most of the genetic variants identified from genome-wide association studies of breast cancer have not been validated in Asian women. No risk assessment model that incorporates both genetic and clinical predictors is currently available to predict breast cancer risk in this population.

METHODS

We analyzed 12 single-nucleotide polymorphisms (SNPs) identified in recent genome-wide association studies mostly of women of European ancestry as being associated with the risk of breast cancer in 3039 case patients and 3082 control subjects who participated in the Shanghai Breast Cancer Study. All participants were interviewed in person to obtain information regarding known and suspected risk factors for breast cancer. The c statistic, a measure of discrimination ability with a value ranging from 0.5 (random classification) to 1.0 (perfect classification), was estimated to evaluate the contribution of genetic and established clinical predictors of breast cancer to a newly established risk assessment model for Chinese women. Clinical predictors included in the model were age at menarche, age at first live birth, waist-to-hip ratio, family history of breast cancer, and a previous diagnosis of benign breast disease. The utility of the models in risk stratification was evaluated by estimating the proportion of breast cancer patients in the general population that could be accounted for above a given risk threshold as predicted by the models. All statistical tests were two-sided.

RESULTS

Eight SNPs (rs2046210, rs1219648, rs3817198, rs8051542, rs3803662, rs889312, rs10941679, and rs13281615), each of which reflected a genetically independent locus, were found to be associated with the risk of breast cancer. A dose-response association was observed between the risk of breast cancer and the genetic risk score, which is an aggregate measure of the effect of these eight SNPs (odds ratio for women in the highest quintile of genetic risk score vs those in the lowest = 1.85, 95% confidence interval = 1.58 to 2.18, P(trend) = 2.5 x 10(-15)). The genetic risk score, the waist-to-hip ratio, and a previous diagnosis of benign breast disease were the top three predictors of the risk of breast cancer, each contributing statistically significantly (P < .001) to the full risk assessment model. The model, with a c statistic of 0.6295 after adjustment for overfitting, showed promise for stratifying women into different risk groups; women in the top 30% risk group accounted for nearly 50% of the breast cancers diagnosed in the general population.

CONCLUSION

A risk assessment model that includes both genetic markers and clinical predictors may be useful to classify Asian women into relevant risk groups for cost-efficient screening and other prevention programs.

Pattern and spectrum of morphology referrals in breast pathology consultation

AIMS

We aimed to identify common reasons for second opinion breast pathology referrals at the Pathology Department, Singapore General Hospital, focusing on queries and diagnostic issues raised by referring clinicians and pathologists.

METHODS

Request forms for breast pathology consultations were retrieved from a specialist's correspondence files consisting of pathologists' referrals, and from centralised laboratory records, comprising clinician-initiated referrals. Clinical and histomorphological queries raised by the referrals were collated.

RESULTS

Of 299 cases evaluated, clinician-initiated referrals (n = 137, 46%) included requests for review of overall histopathology to confirm carcinoma subtype (n = 47), grade (n = 2), size (n = 4), lymphovascular invasion (n = 1) and confirm hormonal receptor and c-erbB-2 assays (n = 33). Also required were: comparison of recurrent with previous lesions (n = 8); settling discrepant diagnoses between two or more prior pathology reports (n = 4); verification of microinvasion (n = 6), in situ carcinomas (n = 6) or atypical ductal hyperplasias (n = 4); delineation of benign (n = 8) and spindle cell lesions (n = 3); to establish a breast origin of metastatic lesions (n = 5); and distinction of carcinoma from lymphoma (n = 2). Pathologist-initiated referrals (n = 162, 54%) sought arbitration between borderline proliferative lesions (n = 46) and papillary lesions (n = 34); verification of microinvasion (n = 23), stromal lesions (n = 16), and carcinoma subtype (n = 13), especially if the patient was young (n = 5); clarification of metaplastic changes (n = 4) and lobular neoplasia (n = 8); and comparison of fibroepithelial lesions (n = 11).

CONCLUSIONS

Clinicians sought a second opinion mainly to verify histological diagnoses and report important pathological details for staging and confirmation of hormonal receptor and c-erbB-2 status prior to therapy. Borderline breast lesions are worrisome for both clinicians and pathologists in view of implications for management.

The acceptance and feasibility of breast cancer screening in the East

Breast cancer, traditionally a disease prevalent among women in the West, has become an increasing disease burden in the East. In Hong Kong, breast cancer is the number one incident cancer in women. In Asian countries, due to the lower incidence rate, population screening is still controversial. Most screening programs are not population-based, and are either self-financed privately or partially subsidized by the government. Since the first government-subsidized screening program was set up in 1991 in Hong Kong, numerous private and government health centres for women have been set up. A dedicated private Breast Care Centre was set up at the Hong Kong Sanatorium and Hospital (HKSH) in 1999. Over an 8-year period from October 1999 to September 2006, 14,596 women were screened, of whom 11,408 were asymptomatic. This study aims to produce the first report on breast screening experience in the largest cohort of asymptomatic Chinese women in the private sector. An overall malignancy detection rate of 2.3 per 1000 screens and a recall rate of 9.2% were found. Despite culture differences and differences in breast characteristics (denser and smaller breasts), breast screening is feasible and acceptable in the East.