The increase of female breast cancer incidence in Japan: emergence of birth cohort effect

Breast cancer incidence trends in Golestan, Iran: An age-period-cohort analysis by ethnic region, 2004-2018

BACKGROUND

We aimed to examine the effects of age, diagnosis year (calendar period) and birth year (cohort) on the incidence trends of breast cancer among Golestan women, Northeast Iran, 2004-2018.

METHODS

Incidence data were obtained by residential status (urban/rural) and ethnic region (Turkmens/non-Turkmens). We calculated age-standardized incidence rates (ASRs) per 100,000 person-years. The estimated annual percentage change (EAPC) were calculated, and age-period-cohort (APC) models fitted to assess non-linear effects of period and cohort as incidence rate ratios (IRRs).

RESULTS

The total number of female breast cancer cases in Golestan, 2004-2018, were 3853, with an overall ASR of 31.3. We found higher rates in urban population (40.5) and non-Turkmens region (38.5) compared to rural area (20.8) and Turkmens region (20.2), respectively. There were increasing trends in incidence rates overall (EAPC= 4.4; 95%CI: 2.2, 6.7), with greater changes in rural areas (EAPC=5.1), particularly among non-Turkmens (EAPC=5.8). The results of the APC analysis indicate the presence of significant non-linear cohort effects with increasing IRRs across successive birth cohorts (IRR=0.1 and IRR= 2.6 for the oldest and the youngest birth cohorts vs. the reference birth cohort, respectively).

CONCLUSION

We found increasing trends in breast cancer incidence among Golestan women over the study period, with disparities in patterns and trends by residence area and ethnic region. The observed cohort effects suggest an increasing prevalence of key risk factors for breast cancer in this Iranian population. Further investigations are warranted to clarify the relationships between determinants such as reproductive factors and ethnicity in the region.

Differential patterns of reproductive and lifestyle risk factors for breast cancer according to birth cohorts among women in China, Japan and Korea

BACKGROUND

The birth cohort effect has been suggested to influence the rate of breast cancer incidence and the trends of associated reproductive and lifestyle factors. We conducted a cohort study to determine whether a differential pattern of associations exists between certain factors and breast cancer risk based on birth cohorts.

METHODS

This was a cohort study using pooled data from 12 cohort studies. We analysed associations between reproductive (menarche age, menopause age, parity and age at first delivery) and lifestyle (smoking and alcohol consumption) factors and breast cancer risk. We obtained hazard ratios (HRs) with 95% confidence intervals (CIs) using the Cox proportional hazard regression analysis on the 1920s, 1930s, 1940s and 1950s birth cohorts.

RESULTS

Parity was found to lower the risk of breast cancer in the older but not in the younger birth cohort, whereas lifestyle factors showed associations with breast cancer risk only among the participants born in the 1950s. In the younger birth cohort group, the effect size was lower for parous women compared to the other cohort groups (HR [95% CI] 0.86 [0.66-1.13] compared to 0.60 [0.49-0.73], 0.46 [0.38-0.56] and 0.62 [0.51-0.77]). Meanwhile, a higher effect size was found for smoking (1.45 [1.14-1.84] compared to 1.25 [0.99-1.58], 1.06 [0.85-1.32] and 0.86 [0.69-1.08]) and alcohol consumption (1.22 [1.01-1.48] compared to 1.10 [0.90-1.33], 1.15 [0.96-1.38], and 1.07 [0.91-1.26]).

CONCLUSION

We observed different associations of parity, smoking and alcohol consumption with breast cancer risk across various birth cohorts.

Urban-Rural Disparity in Birth Cohort Effects on Breast Cancer Incidence

Breast cancer is the most commonly diagnosed cancer among women worldwide. Studies have reported minimal birth cohort effects on the incidence rates of breast cancer in Western countries but have reported notable birth cohort effects in some Asian countries. The risks of breast cancer may also vary within a country. In the present study, we abstracted female invasive breast cancer data from the Taiwan Cancer Registry for the period 1997-2016. We used the age-period-cohort model to compare birth cohort effects on breast cancer incidence rates between urban and rural regions in Taiwan. We identified a notable urban-rural disparity in birth cohort effects on breast cancer incidence rates in women in Taiwan. The incidence rates in the urban regions were higher than those in the rural regions across all cohorts. However, the incidence rates rose faster in the rural regions than in the urban regions across the cohorts. The risks of breast cancer observed for women born in 1992 were approximately 22 and 11 times than those observed for women born in 1917 in rural and urban regions, respectively. The observed gap in breast cancer incidence rates between the urban and rural regions gradually disappeared across the cohorts. Accordingly, we speculate that urbanization and westernization in Taiwan may be the drivers of female breast cancer incidence rates across birth cohorts.

Maternal lifestyle and nutrient intakes during pregnancy and exclusive breastfeeding in relation to risk factors for breast cancer: The Japan Environment and Children's Study

Breastfeeding has many benefits for infant growth and maternal health, such as reducing breast cancer risk. However, data on maternal factors influencing breastfeeding are insufficient. To clarify the associations between maternal lifestyle and diet during pregnancy and exclusive breastfeeding (EBF), we conducted a prospective study of pregnant women within the framework of the Japan Environment and Children's Study (a nationwide birth cohort study). Of 97,413 pregnant women recruited between January 2011 and March 2014, 27,775 with a singleton first live birth whose dietary data during pregnancy and lactation data were complete were eligible. Using logistic regression, we evaluated the associations between lifestyle factors including smoking and prepregnancy body mass index and intake of nutrients (macronutrients, isoflavones, and dietary fiber), some of which are known risk factors of breast cancer, and EBF for one month postpartum (initiation of EBF). To investigate the associations of these factors with EBF for 6 months (continuation of EBF), 9582 women who had successfully completed one-month EBF were further followed up. Smoking and prepregnancy obesity were inversely associated with the initiation and continuation of EBF. Intakes of protein, fat, isoflavone, and dietary fiber were positively associated (p _trend = 0.0001 for dietary fiber), and carbohydrate intake was inversely associated with the initiation of EBF. Dietary fiber intake was also associated with the continuation of EBF (p _trend = 0.048). These findings indicate that maternal lifestyles during pregnancy affect lactation performance. Lifestyle adjustments during pregnancy may have favorable effects on maternal and children's health through successful breastfeeding.

Mortality due to breast cancer in a region of high socioeconomic vulnerability in Brazil: Analysis of the effect of age-period and cohort

INTRODUCTION

Breast cancer is an important public health problem worldwide, with important disparities in incidence, mortality, and survival rates between developed and developing countries due to inequalities regarding access to measures for the prevention and treatment of the disease. In Brazil, there are higher rates of incidence and a downward trend in mortality in regions of greater socioeconomic development.

OBJECTIVE

To evaluate the effect of age, period, and birth cohort on breast cancer mortality in women aged 20 years and older in the states of the Northeast Region of Brazil, an area of high socioeconomic vulnerability, from 1980 to 2019.

METHODS

The death records were extracted from the DATASUS Mortality Information System website (Department of National Health Informatics) from the Ministry of Health of Brazil. Estimable functions were used to estimate the age-period and cohort models (APC) using the Epi library from the R statistical software version 6.4.1.

RESULTS

The average breast cancer mortality rate for the period was 20.45 deaths per 100,000 women. The highest coefficients per 100,000 women were observed in the states of Pernambuco (21.09 deaths) and Ceará (20.85 deaths), and the lowest in Maranhão (13.58 deaths) and Piauí (15.43 deaths). In all of the locations, there was a progressive increase in mortality rates in individuals over 40 years of age, with higher rates in the last five-year period (2015-2019). There was an increase in the risk of death for the five-year period of the 2000s in relation to the reference period (1995-1999) in the Northeast region and in the states of Alagoas, Bahia, Maranhão, Paraíba, and Piauí. In addition, there was an increased risk of death for women born after the 1950s in all locations.

CONCLUSION

The highest mortality rates in all five-year periods analyzed were observed in states with greater socioeconomic development, with an increase in mortality rates in the 2000s, and a higher risk of death in the younger cohorts.

Trends in breast and cervical cancer in India under National Cancer Registry Programme: An Age-Period-Cohort analysis

BACKGROUND

Trend analysis in cancer quantifies the incidence rate and explains the trend and pattern. Breast and cervical cancers are the two most common cancers among Indian women which contributed 39.4 % to the total cancer in India for the year 2020. This study aimed to report the time trends in cancer incidence of breast and cervical cancer using Age-Period-Cohort (APC) model from five Population Based Cancer Registries (PBCRs) in India for the period of 1985-2014.

METHOD

Age-Period-Cohort model was fitted to five PBCRs of Bangalore, Chennai, Delhi, Bhopal and Barshi rural for breast and cervical cancer for 25-74 age-groups. The Estimated Annual Percent Change (EAPC) was calculated. Rate Ratio (RR) of cohort effects were estimated with a constraint of period slope to be zero (p = 0) since cohort has a stronger association with incidence than period.

RESULT

A significant increase was noted in breast cancer in all PBCRs (EAPC, Range: Delhi, 1.2 % to Bangalore, 2.7 %) while significant decrease in cervical cancer (EAPC, Range: Bangalore -2.5 % to Chennai, -4.6 %) from all the PBCRs including Barshi rural during the period. RR estimates for breast cancer showed increasing trend whereas cervical cancer showed decreasing trend in successive birth cohorts across all five PBCRs.

CONCLUSION

In both breast and cervical cancers, a significant age, cohort and period effect was noted in Bangalore, Chennai and Delhi. Despite period effect, the cohort effect was predominant and it may be attributed to the generational changes in risk factors among cancer breast and cervix.

Impact of Birth Cohorts in Breast Cancer Risk Among South Korean Women

BACKGROUND

The incidence of breast cancer among South Korean women, a historically low-risk population, has increased over the past 3 decades, with marked changes in socioeconomic environment by birth cohort.

OBJECTIVES

We investigated associations between breast cancer risk and reproductive factors as well as the impact of birth cohort in those associations.

METHOD

This was a cross-sectional study of data from the Korea National Health and Nutrition Examination Survey for 2013-2016. Data from 10 012 parous women 30 years or older were analyzed using descriptive statistics and Cox multivariate regression after adjusting for socioeconomic status, educational level, occupation, and birth cohort.

RESULTS

Of the reproductive factors considered-age at menarche, number of pregnancies, age at first birth, age at last birth, breastfeeding duration, and use of oral contraceptives-only age at menarche was associated with breast cancer risk. Higher educational level, not having an occupation, and younger birth cohort were also associated with increased risk of breast cancer, with birth cohort the strongest of these impact factors.

CONCLUSION

Whereas the relationship between reproductive factors and breast cancer risk was relatively weak, birth cohort was the most important risk factor for breast cancer.

IMPLICATIONS FOR PRACTICE

The results provide a basis and a rationale for developing birth cohort-based clinical guidelines for breast cancer prevention and early detection, treatment, and survivorship. These findings should also be useful to researchers in other countries experiencing rapid changes in breast cancer incidence.

Impact of reproductive factors on breast cancer incidence: Pooled analysis of nine cohort studies in Japan

Prior studies reported the association of reproductive factors with breast cancer (BC), but the evidence is inconsistent. We conducted a pooled analysis of nine cohort studies in Japan to evaluate the impact of six reproductive factors (age at menarche/age at first birth/number of births/age at menopause/use of female hormones/breastfeeding) on BC incidence. We conducted analyses according to menopausal status at the baseline or at the diagnosis. Hazard ratio (HR) and 95% confidence interval (CI) were estimated by applying Cox proportional-hazards model in each study. These hazard ratios were integrated using a random-effects model. Among 187,999 women (premenopausal: 61,113, postmenopausal: 126,886), we observed 873 premenopausal and 1,456 postmenopausal cases. Among premenopausal women, use of female hormones significantly increased BC incidence (HR: 1.53 [1.04-2.25]). Although P value for trend was not significant for age at first birth and number of births (P for trend: 0.15 and 0.30, respectively), women giving first birth at ages ≥36 experienced significantly higher BC incidence than at ages 21-25 years, and women who had ≥2 births experienced significantly lower BC incidence than nulliparous women. Among postmenopausal women, more births significantly decreased BC incidence (P for trend: 0.03). Although P value for trend was not significant for age at first birth and age at menopause (P for trend: 0.30 and 0.37, respectively), women giving first birth at ages 26-35 years experienced significantly higher BC incidence than at ages 21-25 years, and women with age at menopause: ≥50 years experienced significantly higher BC incidence than age at menopause: ≤44 years. BC incidence was similar according to age at menarche or breastfeeding history among both premenopausal and postmenopausal women. In conclusion, among Japanese women, use of female hormones increased BC incidence in premenopausal women, and more births decreased BC incidence in postmenopausal women.

Contrasting Epidemiology and Clinicopathology of Female Breast Cancer in Asians vs the US Population

BACKGROUND

The incidence of breast cancer among younger East Asian women has been increasing rapidly over recent decades. This international collaborative study systemically compared the differences in age-specific incidences and pathological characteristics of breast cancer in East Asian women and women of predominantly European ancestry.

METHODS

We excerpted analytic data from six national cancer registries (979 675 cases) and eight hospitals (18 008 cases) in East Asian countries and/or regions and, for comparisons, from the US Surveillance, Epidemiology, and End Results program database. Linear regression analyses of age-specific incidences of female breast cancer and logistic regression analyses of age-specific pathological characteristics of breast cancer were performed. All statistical tests were two-sided.

RESULTS

Unlike female colorectal cancer, the age-specific incidences of breast cancer among East Asian women aged 59 years and younger increased disproportionally over recent decades relative to rates in US contemporaries. For years 2010-2014, the estimated age-specific probability of estrogen receptor positivity increased with age in American patients, whereas that of triple-negative breast cancer (TNBC) declined with age. No similar trends were evident in East Asian patients; their probability of estrogen receptor positivity at age 40-49 years was statistically significantly higher (odd ratio [OR] = 1.50, 95% confidence interval [CI] = 1.36 to 1.67, P < .001) and of TNBC was statistically significantly lower (OR = 0.79, 95% CI = 0.71 to 0.88, P < .001), whereas the probability of ER positivity at age 50-59 years was statistically significantly lower (OR = 0.88, 95% CI = 0.828 to 0.95, P < .001). Subgroup analyses of US Surveillance, Epidemiology, and End Results data showed similarly distinct patterns between East Asian American and white American patients.

CONCLUSIONS

Contrasting age-specific incidences and pathological characteristics of breast cancer between East Asian and American women, as well as between East Asian Americans and white Americans, suggests racial differences in the biology.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the management of patients with early breast cancer: a KSMO-ESMO initiative endorsed by CSCO, ISMPO, JSMO, MOS, SSO and TOS

In view of the planned new edition of the most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of primary breast cancer published in 2015, it was decided at the ESMO Asia Meeting in November 2018, by both the ESMO and the Korean Society of Medical Oncology (KSMO), to convene a special face-to-face guidelines meeting in 2019 in Seoul. The aim was to adapt the latest ESMO 2019 guidelines to take into account the ethnic and geographical differences associated with the treatment of early breast cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with early breast cancer representing the oncology societies of Korea (KSMO), China (CSCO), India (ISMPO) Japan (JSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence, and was independent of both the current treatment practices, and the drug availability and reimbursement situations, in the individual participating Asian countries.

Television Viewing Time and Breast Cancer Incidence for Japanese Premenopausal and Postmenopausal Women: The JACC Study

Purpose

The evidence on effects of TV viewing time among premenopausal and postmenopausal women for breast cancer risk remains controversial and limited.

Materials and Methods

A prospective study encompassing 33,276 (17,568 premenopausal, and 15,708 postmenopausal) women aged 40-79 years in whom TV viewing time, menstrual, and reproductive histories were determined by a self-administered questionnaire. The follow-up was from 1988 to 2009 and hazard ratios (HRs) with 95% confidence intervals (CIs) of breast cancer incidence were calculated for longer TV viewing time in reference to shorter TV viewing time by Cox proportional hazard models.

Results

During 16.8-year median follow-up, we found positive associations between TV viewing time and breast cancer incidence with a borderline significant trend among total women and a significant trend among postmenopausal women. Among total women, the multivariable HRs (95% CIs) for risk of breast cancer in reference to < 1.5 hr/day of TV viewing time were 0.89 (0.59-1.34) for 1.5 to < 3.0 hr/day, 1.19 (0.82-1.74) for 3.0 to < 4.5 hr/day, and 1.45 (0.91-2.32) for ≥ 4.5 hr/day (p for trend=0.053) and among postmenopausal women, the corresponding risk estimates were 1.10 (0.42-2.88), 2.54 (1.11-5.80), and 2.37 (0.92-6.10) (p for trend=0.009), respectively.

Conclusion

Prolonged TV viewing time was associated with increased risk of breast cancer, especially among postmenopausal women.

A cross-cultural analysis of salivary cortisol patterns in breast cancer survivors

Aim: In this study, we examined whether Chinese and White women with and without a history of breast cancer exhibit differences in physiological and psychological stress profiles. Methods: Diurnal and reactive salivary cortisol profiles and psychological stress patterns of 41 breast cancer survivors and 58 healthy women were assessed. Results: Breast cancer survivors displayed a blunted acute cortisol response but there was no main effect of ethnocultural membership. Subjective appraisals of stress during the acute stressor revealed a significant interaction between ethnocultural group, health status and time (p = 0.032). Conclusion: Our results support the existing literature though suggest group differences in the appraisal of stress; thus, underscoring the importance of cultural sensitivity and awareness among clinicians and existing programs.

Does guideline non-adherence result in worse clinical outcomes for hormone receptor-positive and HER2-negative metastatic breast cancer in premenopausal women?: result of an institution database from South Korea

Background

In this study, we observe the patterns initial palliative treatment for premenopausal patients with HR-positive/HER2-negative MBC and determine if nonadherence to clinical guidelines are associated with worse clinical outcomes in terms of progression-free survival (PFS) and overall survival (OS) in the South Korean population.

Methods

A retrospective review was performed for premenopausal patients diagnosed with HR-positive/HER2-negative MBC between October 1997 and May 2016 who received palliative systemic treatments at a large tertiary medical center. Survival outcomes were analyzed according to the palliative treatment received prior to disease progression.

Results

The review identified a total of 272 premenopausal patients meeting study criteria, whose median age was 39 years. Endocrine therapy was the initial treatment in 137 patients (Group 1) with chemotherapy as initial treatment in 135 patients. In the latter group, chemotherapy was continued in 78 patients (Group 2), whereas chemotherapy was switched to endocrine treatment in 57 patients prior to any disease progression (Group 3). Both PFS and OS were significantly longer for chemotherapy-endocrine therapy (median PFS 18.2 months and OS 85.2 months) than for chemotherapy-alone (median PFS 12.6 months and OS 45.5 months) or endocrine therapy-alone (median PFS 7.0 months and OS 57.3 months) (all p values < 0.01). In multivariate analysis, chemotherapy-endocrine therapy was an independent predictive value for improved PFS and OS (hazard ratio [HR] 0.33, 95% CI 0.20–0.52, p <  0.001; HR 0.38, 95% CI 0.19–0.73, p = 0.004).

Conclusions

In our study population, chemotherapy alone was not objectively inferior to endocrine therapy as the initial palliative treatment. In addition, chemotherapy followed by endocrine therapy was associated with objective higher response rate than endocrine therapy alone. Further studies should explore the relationship between non-adherent treatment patterns and patient outcomes across the largely premenopausal breast cancer populations across Asian countries.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5258-9) contains supplementary material, which is available to authorized users.

Trends in incidence and mortality of female breast cancer during transition in Central China

PURPOSE

Following the implementation of breast cancer (BC) control strategies for years in Central China, the outcome needs to be evaluated and further strategies based on long-term surveillance should be formulated. Therefore, we examined the trends of BC incidence and mortality during 1990-2014 and projected them to 2024 in Wuhan, Central China.

PATIENTS AND METHODS

The incidence and mortality data of BC were extracted from the Wuhan Cancer Registry. The average annual percentage changes (AAPCs) of the age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) were analyzed using Joinpoint regression. The Nordpred R-package was used to project BC incidence and mortality between 2015 and 2024. The age-period-cohort analysis was applied to evaluate the age, period, and cohort effects on the trends of BC incidence and mortality.

RESULTS

Overall, the ASIR increased markedly from 20.01 to 44.26 per 100,000 (AAPC=3.3%, 95% CI: 1.7%, 5.0%) during 1990-2014, and it was projected to keep increasing in the next decade (AAPC=3.0%, 95% CI: 2.0%, 4.1%). The ASMR of BC leveled off during the study period (AAPC=0.4%, 95% CI: -0.2%, 0.9%). The BC mortality of the older group (aged 50-79 years) showed significant upward trends in both observed and projected periods. Strong age, period, and cohort effects were observed in BC incidence, and BC mortality was significantly driven by age and cohort effects.

CONCLUSION

The ASIR in Wuhan was approaching those areas with the highest BC risk in China, and the evident increase in BC incidence suggested that prior strategies for BC control should be adopted. In particular, further strategies for reducing BC mortality in older age groups should be reinforced in Wuhan, Central China.

Association of pregnancy and mortality in women diagnosed with breast cancer: A Nationwide Population Based Study in Taiwan

We examined the associations between breast cancer diagnosed during pregnancy and up to 5 years postpartum and total mortality. Breast cancer patients were identified from the Taiwan Cancer Registry (2002-2014). All pregnancies up to 5 years before breast cancer diagnosis were abstracted from the National Health Insurance database and data were then linked to the Taiwan National Death Certificate Database. Follow-up was calculated from the date of breast cancer diagnosis to the date of death or 31 December, 2014, whichever came first. The hazard ratios (HRs) and the 95% confidence intervals (CI) of the association between pregnancy and total mortality were estimated using Cox proportional hazard models. Among the 30,230 breast cancer patients, 90 were diagnosed during pregnancy, 347 within a year postpartum, and 1993 during 1-5 years postpartum. By the end of 2014, 2,920 patients were dead. The major cause of death was breast cancer (89%). Compared to patients without pregnancy records, the HRs were 1.42 (95% CI = 0.83-2.45) for patients diagnosed during pregnancy, 1.29 (0.96-1.74) for those diagnosed within a year postpartum, 1.27 (0.95-1.70) for those diagnosed within 1 to 2 years postpartum, and 1.06 (0.88-1.27) for those diagnosed ≥2 to 5 years postpartum, after adjustment for tumor characteristics and treatment. Subgroup analyses revealed an increased risk of mortality for patients diagnosed within a year postpartum in ER+ cancers (HR = 2.11, 95% CI = 1.28-3.47). Our results suggested a recent pregnancy may be associated with higher mortality among ER+ patients.

Improved overall survival over recent decades in patients with hormone-receptor-positive, HER2-negative breast cancer: a single-center retrospective analysis of prognostic factors

Background

Hormone receptor (HR)-positive HER2-negative breast cancer (BC) rates and associated mortality have been increasing among Japanese women. It is unclear whether the prognosis of these patients has improved.

Methods

We retrospectively analyzed 1806 Japanese women with operable invasive HR-positive HER2-negative BC, who underwent complete resection at the National Cancer Center Hospital East between July 1992 and December 2010. We investigated whether overall survival (OS) and recurrence-free survival (RFS) had improved by comparing the 4-year periods 1992-96, 1997-2001, 2002-06, and 2007-10. The prognostic factors were evaluated using uni- and multivariate analyses.

Results

The number of ER- and PgR-positive cancers had increased over the years (P < 0.001). Tumor sizes and numbers of involved lymph nodes both gradually decreased (P < 0.001 for both). OS and RFS of all patients significantly improved in each of the periods analyzed: 5-year OS was 92.6%, 94.8%, 95.4% and 97.6% (P < 0.001, Log-rank), and 5-year RFS was 82.1%, 82.8%, 88.6% and 94.5% (P < 0.001) in 1992-96, 1997-2001, 2002-06 and 2007-10, respectively. In multivariate analysis, the history of adjuvant AI and that of TAM had positive-correlation with RFS.

Conclusions

The prognosis for HR-positive HER2-negative BC patients after surgical therapy has improved, resulting in longer OS and RFS across the study periods. These changes could be associated with early detection of tumor and history of hormone therapy.

Establishment of two basal-like breast cancer cell lines with extremely low tumorigenicity from Taiwanese premenopausal women

The research of carcinogenetic mechanisms of breast cancer in different ethnic backgrounds is an interesting field, as clinical features of breast cancers vary among races. High premenopausal incidence is distinctive in East-Asian breast cancer. However, human cell lines derived from Asian primary breast tumor are rare. To provide alternative cell line models with a relevant genetic background, we aimed to establish breast cancer cell lines from Taiwanese patients of Han-Chinese ethnicity. Fresh tissue from mammary tumors were digested into organoids, plated and grown in basal serum-free medium of human mammary epithelial cells (HuMEC) with supplements. Cells were further enriched by positive selection with CD326 (epithelial cell adhesion molecule; EpCAM)-coated micro-magnetic beads. Two breast cancer cell lines derived from premenopausal women were successfully established by this method, and named Chang-Gung Breast Cancer 01 (CGBC 01) and 02 (CGBC 02). These two cell lines had a similar phenotype with weak expression of estrogen receptor (ER), progesterone receptor (PR), and without amplification of receptor tyrosine protein kinase erbB-2 (HER2/neu). Genome-wide Single Nucleotide Polymorphism (SNP) array showed multiple copy number alterations in both cell lines. Based on gene expression profiles, CGBC 01 and 02 were clustered into basal-like subtype with reference to the breast cancer cell line gene expression database. The tumorigenicity of both cell lines was extremely low in both anchorage-independence assay and transplantation into the mammary fat pads of nude mice. CGBC 01 and CGBC 02 are low tumorigenic breast cancer cell lines, established from Han-Chinese premenopausal breast cancer patients, which serve as in vitro models in studying the biological features of Asian breast cancer.

Breast cancer risk factors and mammographic density among high-risk women in urban China

Elevated mammographic density (MD) is an established breast cancer risk factor. Studies examining relationships between MD and breast cancer risk factors are limited in China, where established breast cancer risk factors are less prevalent but dense breasts are more prevalent than Western countries. This study included 11,478 women (45-69 years; 36% premenopausal) participating in an ongoing national cancer screening program in 11 urban provinces in China and predicted as having high-risk for breast cancer. Polytomous logistic regression was performed to assess associations between MD and risk factors by comparing each higher Breast Imaging Reporting and Data System (BI-RADS) category (2, 3, or 4) to the lowest category (BI-RADS, 1). We found associations of increasing age, body mass index, weight, postmenopausal status, and parity with lower MD. Higher levels of education, increasing height, and later first birth were associated with higher MD. These associations did not vary by menopausal status. Additionally, the association between longer period of breastfeeding and lower MD was seen among postmenopausal women only (P_interaction = 0.003). Having first-degree relatives with breast cancer diagnosed before 50 years was associated with lower MD only among premenopausal women (P_interaction = 0.061). We found effects of established breast cancer risk factors on MD showed similar directions in Chinese and Western women, supporting the hypothesis that MD represents cumulative exposure to breast cancer risk factors over the life course. Our findings help to understand the biological basis of the association of MD with breast cancer risk and have implications for breast cancer prevention research in China.

Disparities of time trends and birth cohort effects on invasive breast cancer incidence in Shanghai and Hong Kong pre- and post-menopausal women

Background

Breast cancer is the leading cause of cancer morbidity among Shanghai and Hong Kong women, which contributes to 20–25% of new female cancer incidents. This study aimed to describe the temporal trend of breast cancer and interpret the potential effects on the observed secular trends.

Methods

Cancer incident data were obtained from the cancer registries. Age-standardized incidence rate was computed by the direct method using the World population of 2000. Average annual percentage change (AAPC) in incidence rate was estimated by the Joinpoint regression. Age, period and cohort effects were assessed by using a log-linear model with Poisson regression.

Results

During 1976–2009, an increasing trend of breast cancer incidence was observed, with an AAPC of 1.73 [95% confidence interval (CI): 1.54–1.92)] for women in Hong Kong and 2.83 (95% CI, 2.26–3.40) in Shanghai. Greater upward trends were revealed in Shanghai women aged 50 years old or above (AAPC = 3.09; 95% CI, 1.48–4.73). Using age at 50 years old as cut-point, strong birth cohort effects were shown in both pre- and post-menopausal women, though a more remarkable effect was suggested in Shanghai post-menopausal women. No evidence for a period effect was indicated.

Conclusions

Incidence rate of breast cancer has been more speedy in Shanghai post-menopausal women than that of the Hong Kong women over the past 30 years. Decreased birth rate and increasing environmental exposures (e.g., light-at-night) over successive generations may have constituted major impacts on the birth cohort effects, especially for the post-menopausal breast cancer; further analytic studies are warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3359-5) contains supplementary material, which is available to authorized users.

Risk of secondary cancers in women with breast cancer and the influence of radiotherapy: A national cohort study in Taiwan

Breast cancer is the most common cancer in women worldwide; thus, the prolongation of survival, and the incidence and risk factors, including radiotherapy, for developing secondary malignancies are important. We compared the incidence of secondary and new primary cancers in women with breast cancer (CA) and well-matched for age, geographic region, and monthly income cancer-free controls (CA). The risk for secondary cancers with and without radiotherapy was also compared in CA women. We enrolled 2422 CA patients and CA 12,110 controls. In a 4-year follow-up, the secondary cancers risk was significant in the CA group (adjusted hazard ratio [AHR]: 1.59; 95% confidence interval [CI]: 1.17-2.18). Only the risk of uterine cancer was significant compared with the controls (AHR: 6.30; 95% CI: 2.28-17.38). CA patients and <50 years old had a higher risk for secondary cancers. Developing secondary cancers was significant in the first follow-up year (AHR: 1.51; 95% CI: 1.11-2.06). Radiotherapy had no significant effect on the CA group, but it was significant (P = 0.0298) in women ≥60 years old (elderly). We recommend monitoring secondary cancers in CA women, especially those <50 years old, and during the first year of follow-up. Radiotherapy should be used more carefully in elderly CA women.

The real-world cost-effectiveness of adjuvant trastuzumab in HER-2/neu-positive early breast cancer in Taiwan

BACKGROUND

Trastuzumab was considered a cost-effective adjuvant treatment for HER 2-positive early breast cancer. Since 2010, the Taiwanese National Health Insurance (NHI) has started to reimburse for 1-year adjuvant treatment. This study aims to provide an updated cost-effectiveness analysis from the NHI perspective, which explores assumptions about long-term cardiac toxicity and treatment benefit of 1-year adjuvant treatment sequentially after chemotherapy.

METHODS

A Markov model was used to evaluate the cost-effectiveness of 1-year adjuvant trastuzumab for HER-2/neu positive early breast cancer over a 20-year life-time horizon. A probability sensitivity analysis using Monte Carlo simulation was performed to characterize uncertainties in the expected outcomes, which are expressed as an incremental costs effectiveness ratio (ICER, cost/QALY). A willingness-to-pay threshold of 3-times the per capita gross domestic product was adopted according to the WHO definition. The Taiwan per capita gross domestic product in 2015 was US$22,355; thus, a threshold was considered as NT$2,011,950 (US$67 065, 1USD =30 NTD in 2015).

RESULTS

The model showed that adjuvant trastuzumab treatment in HER-2/neu positive early breast cancer yielded 1.631 quality-adjusted life-years (QALY) compared with no trastuzumab treatment. The ICER was US $51,863 per QALY gained in the base-case scenario. The Monte Carlo simulation by varying all variables simultaneously demonstrated that the probability of cost-effectiveness at the willingness-to-pay threshold of US$67,065 was 50% for 1-year adjuvant trastuzumab.

CONCLUSIONS

From this real-world study, 1-year adjuvant trastuzumab treatment is likely to be a cost-effective therapy for patients with HER-2 positive breast cancer at the willingness-to-pay threshold of 3-times GDP per capita in Taiwan.

Descriptive epidemiology of breast cancer in China: incidence, mortality, survival and prevalence

Breast cancer is the most common neoplasm diagnosed amongst women worldwide and is the leading cause of female cancer death. However, breast cancer in China is not comprehensively understood compared with Westernised countries, although the 5-year prevalence statistics indicate that approximately 11 % of worldwide breast cancer occurs in China and that the incidence has increased rapidly in recent decades. This paper reviews the descriptive epidemiology of Chinese breast cancer in terms of incidence, mortality, survival and prevalence, and explores relevant factors such as age of manifestation and geographic locations. The statistics are compared with data from the Westernised world with particular emphasis on the United States and Australia. Potential causal agents responsible for differences in breast cancer epidemiology between Chinese and other populations are also explored. The need to minimise variability and discrepancies in methods of data acquisition, analysis and presentation is highlighted.

The impact of breast cancer-specific birth cohort effects among younger and older Chinese populations

Historically low breast cancer incidence rates among Asian women have risen worldwide; purportedly due to the adoption of a "Western" life style among younger generations (i.e., the more recent birth cohorts). However, no study has simultaneously compared birth cohort effects between both younger and older women in different Asian and Western populations. Using cancer registry data from rural and urban China, Singapore and the United States (1990-2008), we estimated age-standardized incidence rates (ASR), annual percentage change (EAPC) in the ASR, net drifts, birth cohort specific incidence rates and cohort rate ratios (CRR). Younger (30-49 years, 1943-1977 birth cohorts) and older women (50-79 years; 1913-1957 birth cohorts) were assessed separately. CRRs among Chinese populations were estimated using birth cohort specific rates with US non-Hispanic white women (NHW) serving as the reference population with an assigned CRR of 1.0. We observed higher EAPCs and net drifts among those Chinese populations with lower ASRs. Similarly, we observed the most rapidly increasing cohort-specific incidence rates among those Chinese populations with the lowest baseline CRRs. Both trends were more significant among older than younger women. Average CRRs were 0.06-0.44 among older and 0.18-0.81 among younger women. Rapidly rising cohort specific rates have narrowed the historic disparity between Chinese and US NHW breast cancer populations particularly in regions with the lowest baseline rates and among older women. Future analytic studies are needed to investigate risk factors accounting for the rapid increase of breast cancer among older and younger women separately in Asian populations.

Dietary patterns and breast cancer risk in a prospective Japanese study

BACKGROUND

The association between dietary patterns and breast cancer has been inconsistent.

METHODS

This study examined associations between dietary patterns and risk of developing breast cancer among 23,172 women from the Japan Collaborative Cohort Study, including 119 incidences of breast cancer diagnosed during a median 16.9-year follow-up period. Factor analysis was conducted to obtain dietary patterns, and Cox proportional models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 % CI) for breast cancer morbidity.

RESULTS

Three dietary patterns were identified: ''vegetable pattern'' (vegetables, potatoes, seaweed, tofu, fruits, fresh fish, eggs, and miso soup); ''animal food pattern'' (meat, deep-fried foods, fried vegetables, fish paste and salt-preserved fish); and "dairy product pattern'' (milk, dairy products, fruits, coffee and tea). After adjusting for potential confounders, the vegetable and dairy product patterns were not significantly associated with risk of breast cancer. However, the animal food pattern was significantly associated with a decreased risk of breast cancer morbidity among premenopausal women by HR 0.47 for the 2nd tertile (95 % CI 0.22-1.00) and HR 0.42 for the 3rd tertile (95 % CI 0.18-0.93), compared with the bottom tertile (p for trend 0.04).

CONCLUSION

We found no significant association between the vegetable and dairy product dietary patterns and breast cancer risk; however, an animal product diet may reduce risk of breast cancer among premenopausal Japanese women.

Secular Trends of Breast Cancer in China, South Korea, Japan and the United States: Application of the Age-Period-Cohort Analysis

To describe the temporal trends of breast cancer mortality in East Asia and to better understand the causes of these trends, we analyzed the independent effects of chronological age, time period and birth cohort on breast cancer mortality trends using age-period-cohort (APC) analysis. We chose three main countries in East Asia, namely China, South Korea, and Japan, which have reported death status to the WHO Mortality Database, and used the United States as a comparison population. Our study shows that in general, breast cancer mortality rates in females increased in all three East Asian countries throughout the study period. By APC analysis, we confirmed that there is, in fact, a difference in age-specific mortality rate patterns between the Eastern and the Western countries, which is presumably caused by the two-disease model. While the cause of the decrease from approximately the 1950s generation is still in question, we believe that increasing general awareness and improvements in the health-care system have made a significant contribution to it. Although the age and cohort effects are relatively strong, the period effect may be a more critical factor in the mortality trend, mainly reflecting the increase in exposures to carcinogens and behavioral risk factors.

Current Status and Future Projections of Breast Cancer in Asia

Asia is the world's largest continent comprising about 3/5 of the human population. Breast cancer is the most common type of cancer and the second leading cause of cancer-related deaths among women in Asia, accounting for 39% of all breast cancers diagnosed worldwide. The incidence of breast cancer in Asia varies widely across the continent and is still lower than in Western countries, but the proportional contribution of Asia to the global breast cancer rates is increasing rapidly in parallel to the socioeconomic development. However, the mortality-to-incidence ratios are much higher for Asia than for Western countries. Most Asian countries are low- and middle-income countries (LMICs) where breast cancer presents at a younger age and a later stage, and where patients are more likely to die from the disease than those in Western countries. Moreover, diagnostic workup, treatment and palliative services are inadequate in most Asian LMICs. In this review, we present an overview of the breast cancer risk factors and epidemiology, control measures, and cancer care among Asian countries.

Age-Period-Cohort Analysis of Female Breast Cancer Mortality in Korea

Purpose

Despite the low mortality rate of breast cancer among women in Korea, the breast cancer mortality rate has increased. The aim of this study was to examine trends in breast cancer mortality from 1983 to 2012 in Korea, assessing the importance of age, period, and birth cohort as risk factors.

Materials and Methods

Data on the annual number of deaths due to female breast cancer and on female population statistics from 1983 to 2012 were obtained from Statistics Korea. A log-linear Poisson age-period-cohort model was used to estimate age, period, and cohort effects.

Results

The increasing breast cancer mortality can be explained predominantly by a birth cohort effect: the risk of breast cancer death showed a steady increase until the 1968 birth cohort, and decreased thereafter. There was a sharp increase in the magnitude of the age effect up to 60 years old, then a moderate increase in the effect during the sixties, followed by another sharp increase from 70 years old. The period effect on breast cancer mortality seems negligible based on its adjusted relative risk, even though it was statistically significant after adjusting for age and cohort effects.

Conclusion

In this study, the mortality pattern of breast cancer in Korea can be explained predominantly by a birth cohort effect. Hence, the overall mortality rate of breast cancer may increase for a while, and show a gradual decrease in the future, which will start from the younger age group.

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.

The contribution of mammography screening to breast cancer incidence trends in the United States: an updated age-period-cohort model

BACKGROUND

The impact of screening mammography on breast cancer incidence is difficult to disentangle from cohort- and age-related effects on incidence.

METHODS

We developed an age-period-cohort model of ductal carcinoma in situ (DCIS) and invasive breast cancer incidence in U.S. females using cancer registry data. Five functions were included in the model to estimate stage-specific effects for age, premenopausal birth cohorts, postmenopausal birth cohorts, period (for all years of diagnosis), and a mammography period effect limited to women ages ≥ 40 years after 1982. Incidence with and without the mammography period effect was calculated.

RESULTS

More recent birth cohorts have elevated underlying risk compared with earlier cohorts for both pre- and postmenopausal women. Comparing models with and without the mammography period effect showed that overall breast cancer incidence would have been 23.1% lower in the absence of mammography in 2010 (95% confidence intervals, 18.8-27.4), including 14.7% (9.5-19.3) lower for invasive breast cancer and 54.5% (47.4-59.6) lower for DCIS. Incidence of distant-staged breast cancer in 2010 would have been 29.0% (13.1-48.1) greater in the absence of mammography screening.

CONCLUSIONS

Mammography contributes to markedly elevated rates of DCIS and early-stage invasive cancers, but also contributes to substantial reductions in the incidence of metastatic breast cancer.

IMPACT

Mammography is an important tool for reducing the burden of breast cancer, but future work is needed to identify risk factors accounting for increasing underlying incidence and to distinguish between indolent and potentially lethal early-stage breast cancers that are detected via mammography.

Prevalence and clinical outcomes of young breast cancer (YBC) patients according to intrinsic breast cancer subtypes: Single institutional experience in Korea

The purpose of our study was to investigate and identify comprehensively the clinicopathological features and long-term outcome of young breast cancer (YBC) according to intrinsic subtype. We analyzed clinical and pathological characteristics of 2844 women who were diagnosed with invasive breast cancer from 2000 to 2007 and the treatment outcomes by age at diagnosis. The median age of the patients was 46 years (range, 21-83 years), and we divided them into three age group: ≤35 years (Group 1), 36-50 years (Group 2), and >50 years (Group 3). During a median follow-up of 100 months, the 5-year recurrence-free survival rate (RFSR) and overall survival rate (OSR) were 90.8% and 94.6%, respectively. The 10-year estimated RFSR and OSR were 81.9% and 86.9%, respectively. The prognosis of TN subtype appeared not to be worse than that of other subtypes in Group 1. In Group 1 alone (≤35 years), subtype was not identified as an independent risk factor for distant recurrence-free survival (DRFS) in a Cox-regression multivariate model (hazard ratio, 0.85; 95% CI, 0.68-1.06; p = 0.148). This analysis revealed a very high prevalence of YBC in this cohort. The poor outcomes of YBC patients might result from an increased frequency of triple negative (TN)/HER2 subtypes and the more aggressive clinical behavior of ER-positive tumors compared with older patients. Further research to elucidate the biologic difference of the ER+ tumors of YBC patients is warranted.

Mortality of breast cancer in Taiwan, 1971-2010: temporal changes and an age-period-cohort analysis

The current paper describes the age, period and cohort effects on breast cancer mortality in Taiwan. Female breast cancer mortality data were collected from the Taiwan death registries for 1971-2010. The annual percentage changes, age- standardised mortality rates (ASMR) and age-period-cohort model were calculated. The mortality rates increased with advancing age groups when fixing the period. The percentage change in the breast cancer mortality rate increased from 54.79% at aged 20-44 years, to 149.78% in those aged 45-64 years (between 1971-75 and 2006-10). The mortality rates in the 45-64 age group increased steadily from 1971 to 1975 and 2006-10. The 1951 birth cohorts (actual birth cohort; 1947-55) showed peak mortalities in both the 50-54 and 45-49 age groups. We found that the 1951 birth cohorts had the greatest mortality risk from breast cancer. This might be attributed to the DDT that was used in large amounts to prevent deaths from malaria in Taiwan. However, future researches require DDT data to evaluate the association between breast cancer and DDT use.

Breast cancer in China

The health burden of cancer is increasing in China, with more than 1·6 million people being diagnosed and 1·2 million people dying of the disease each year. As in most other countries, breast cancer is now the most common cancer in Chinese women; cases in China account for 12·2% of all newly diagnosed breast cancers and 9·6% of all deaths from breast cancer worldwide. China's proportional contribution to global rates is increasing rapidly because of the population's rising socioeconomic status and unique reproductive patterns. In this Review we present an overview of present control measures for breast cancer across China, and emphasise epidemiological and socioeconomic diversities and disparities in access to care for various subpopulations. We describe demographic differences between China and high-income countries, and also within geographical and socioeconomic regions of China. These disparities between China and high-income countries include younger age at onset of breast cancer; the unique one-child policy; lower rates of provision and uptake for screening for breast cancer; delays in diagnosis that result in more advanced stage of disease at presentation; inadequate resources; and a lack of awareness about breast cancer in the Chinese population. Finally, we recommend key measures that could contribute to improved health outcomes for patients with breast cancer in China.

Descriptive epidemiological study of food intake among Japanese adults: analyses by age, time and birth cohort model

BACKGROUND

Although food and nutrient consumption among the Japanese population, known to have one of the longest life expectancies in the world, has changed markedly after World War II, little is known about the influences age, time and birth cohort have had. The present study examined the effects age, time and birth cohort have had on intake of 14 food groups from 1989 to 2009, using published data from the National Health and Nutrition Survey in Japan.

METHODS

The survey included 575 adults (271 men and 304 women) in 1989, 8431 (3952 men and 4479 women) in 1999 and 5632 (2629 men and 3003 women) in 2009. The effects of age on energy-adjusted food intakes defined by gender and birth cohort (birth in 1930-1939, 1940-1949, 1950-1959, 1960-1969, 1970-1979) were estimated using the mean polish process.

RESULTS

Intakes of meat and confectionary increased whereas those of milk and dairy products, sugar, and fats and oils decreased from 1989 to 2009. Both men and women in the 1940's birth cohort consumed more fruit, although differences in food intake by birth cohort were less discernible. Furthermore, meat, fats and oils, and wheat intake decreased while fruits, fish, beans and vegetables consumption increased with aging in both men and women.

CONCLUSIONS

The present analysis suggests intakes of meat and confectionary have increased in Japan over the past 20 years regardless of age and generation. Also, younger individuals are less likely to consume fruits, fish, beans and vegetables regardless of the birth cohort and time period. Differences in food group consumption by birth cohorts born between 1930 and 1979 were not obvious. The first indication of these findings would be that in order to avoid ongoing increases in meat and confectionery intake, the public health strategy should target the whole Japanese population. Secondly, intervening with the diet of younger individuals, especially today, would be reasonable as it is unknown whether today's younger individuals will adopt a healthier diet when they age as the other generations did.

Cigarette smoking and breast cancer risk in relation to joint estrogen and progesterone receptor status: a case-control study in Japan

An association of cigarette smoking with breast cancer risk has been hypothesized. However, results from previous studies have been inconsistent. This case-control study investigated the association of cigarette smoking with breast cancer risk in terms of estrogen-receptor/progesterone-receptor (ER/PgR) status. From among female patients aged 30 years and over admitted to a single hospital in Japan between 1997 and 2011, 1,263 breast cancer cases (672 ER+/PgR+, 158 ER+/PgR-, 22 ER-/PgR+, 308 ER-/PgR- and 103 missing) and 3,160 controls were selected. History of smoking (ever, never), some smoking-related measures, and passive smoking from husbands (ever, never) were assessed using a self-administered questionnaire. Polytomous logistic regression and tests for heterogeneity across ER+/PgR + and ER-/PgR- were conducted. For any hormone receptor subtype, no significant association was observed between history of smoking (ever, never) and breast cancer risk. Analysis of smoking-related measures revealed that starting to smoke at an early age of ≤19 years was significantly associated with an increased risk of postmenopausal ER-/PgR- cancer (odds ratio = 7.01, 95% confidence interval: 2.07-23.73). Other measures of smoking such as the number of cigarettes per day, the duration of smoking, and start of smoking before the first birth were not associated with breast cancer risk for any receptor subtype. There was no association between passive smoking (ever, never) and breast cancer risk for any of the four subtypes. These results indicate that history of smoking and passive smoking from husbands may have no overall effect on breast cancer risk for any hormone receptor subtype. However, it is possible that women who start to smoke as teenagers may have a higher risk of developing postmenopausal ER-/PgR- cancer. Further studies are needed to clarify the association of smoking with breast cancer risk, especially the role of starting to smoke at an early age.

Endoscopy-assisted breast-conserving surgery for early breast cancer

INTRODUCTION

Endoscopic surgery is reportedly associated with smaller scars and greater patient satisfaction. Herein we evaluate the early results of endoscopy-assisted breast-conserving surgery(E-BCS).

METHODS

Between May 2009 and October 2010, 61 women with breast cancer underwent E-BCS. We performed E-BCS on patients with tumors measuring less than 2 cm, without skin or pectoralis muscles invasion. Any patients with microcalcified lesions or axillary lymph node metastasis were excluded. We used an endoscopic vein retractor to dissect the dorsal layer of the mammary gland from a small axillar incision. We dissected the subcutaneous layer and cut the mammary gland vertically from a periareolar incision. We evaluated the clinicopathological characteristics, the surgical outcomes, and early cosmetic results.

RESULTS

The mean age of the patients was 58.5 years, and the mean tumor size was 1.4 cm. Sentinel node biopsy was positive in seven patients, all of whom underwent axillary node dissection. An additional intraoperative resection of the breast was performed in 12 patients. The mean length of the operation was 167 min, and the mean blood loss was 27 mL. Eight patients received a boost to the tumor bed. The cosmetic results were satisfactory, and the wound scar was inconspicuous in most patients.

CONCLUSION

Herein we demonstrate that E-BCS is a feasible and safe procedure for patients with early breast cancer. It allows for a better cosmetic scar location and offers patients favorable aesthetic results in the short-term follow-up results.

Differential impact of body mass index and its change on the risk of breast cancer by molecular subtype: A case-control study in Japanese women

Body mass index (BMI) is an independent risk factor for luminal-type breast cancer in Western populations. However, it is unclear whether the impact of BMI differs according to breast cancer subtype in Japanese populations. We conducted a case–control study with 715 cases and 1430 age- and menopausal status-matched controls to evaluate the associations of BMI and its change (from age 20 years to the current age) with breast cancer risk. We applied conditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Tumor subtypes were divided into four subtypes, namely the luminal, luminal/HER2, HER2-rich, and triple-negative subtypes. Current BMI and BMI change were positively associated with postmenopausal breast cancer risk. On stratified analysis by tumor subtype, we observed associations between current BMI and BMI change and postmenopausal breast cancer risk for the luminal subtype, with OR for each 1 kg/m² increase in current BMI of 1.14 (95% CI: 1.07 - 1.20) and the corresponding OR of BMI change of 1.16 (1.09 - 1.23) (each P_trend < 0.001). Additionally, we found the same tendency for the triple-negative subtype, with the OR for a 1 kg/m² increase in current BMI of 1.21 (1.05 - 1.39) and that for BMI change of 1.18 (1.02 - 1.36) (P_trend was 0.008 and 0.024, respectively). In premenopausal women, a suggestive inverse association was observed between BMI change and breast cancer risk for the luminal subtype only, with OR of BMI change of 0.93 (0.87 - 1.00, P_trend = 0.054). No association was seen between BMI at age 20 years and risk of any tumor subtype. In conclusion, BMI and its change are associated with the risk of both luminal and triple-negative breast cancer among postmenopausal Japanese women. These findings suggest the etiological heterogeneity of breast cancer among tumor subtypes.

Association between body mass index and breast cancer intrinsic subtypes in Japanese women

The purpose of this study was to examine the association between body mass index (BMI) and breast cancer intrinsic subtypes in Japanese women. A more complete understanding of the subtypes of breast cancer may elucidate the mechanisms affecting the etiology and mortality associated with each subtype. Tumor data on 531 invasive breast cancer cases subtyped by estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (Her2) status were obtained [luminal A, luminal B, triple-negative (TN) and Her2-type]. Demographics (age at diagnosis, menopausal status and BMI) were collected from medical records. Case-only odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression, adjusting for age at diagnosis. Of the 531 cases, 333 (62.7%) were luminal A, 85 (16.0%) were luminal B, 43 (8.1%) were Her2-type and 70 (13.2%) were TN. Compared with luminal A cases, premenopausal TN cases were more likely to be obese (OR, 4.11; 95% CI, 1.10–14.40), while postmenopausal TN cases were more likely to be underweight (OR, 3.14; 95% CI, 1.19–8.01). Premenopausal luminal B cases were likely to be underweight or obese, while luminal B and Her2-type cases were likely to be underweight. In the present study, significant heterogeneity of associations between BMI and tumor subtypes was observed. Breast cancer subtypes may have various etiologies associated with each subtype.

Age Interactions in Breast Cancer: An Analysis of a 10-Year Multicentre Study in China

OBJECTIVES: The effects of age at diagnosis on the clinical characteristics of breast cancer and trends over time were investigated in Chinese women. METHODS: Data from 4211 women with pathologically confirmed primary breast cancer collected between 1999 and 2008 for a multicentre retrospective study were analysed according to age at diagnosis. RESULTS: Age at diagnosis ranged from 21 to 86 years, with a mean of 48.7 years, and was shown to be significantly related to tumour size, lymph node status, hormone receptor status and human growth factor receptor-2 status, but not to pathological type or tumour, node, metastasis stage. The age-corrected proportion of patients aged 50 – 64 years at diagnosis increased significantly between 1999 and 2008. There was a significant difference in the age-corrected distribution of age at diagnosis in China compared with Western countries. CONCLUSIONS: Age at diagnosis is related to the clinical and pathological characteristics of breast cancer. The age at diagnosis in China increased over the decade from 1999 to 2008, but is still lower than in Western countries.

Being breastfed in infancy and adult breast cancer risk among Japanese women

OBJECTIVE

Being breastfed in infancy has been hypothesized to influence subsequent breast cancer risk. In a hospital-based case-control study, we investigated the relationship between having been breastfed and breast cancer risk, both overall and separately among female subjects with different birth years.

METHODS

The study subjects included 571 cases and 2,155 controls admitted to a single hospital in Miyagi Prefecture, Japan, between 1997 and 2005. History of having been breastfed was assessed with a self-administered questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using logistic regression.

RESULTS

After adjustment for known risk factors, no association for having been breastfed was observed overall (OR = 1.20; 95% CI: 0.82-1.76). Analysis stratified according to birth year (<1950, ≥1950) demonstrated heterogeneity in the association for having been breastfed between the two birth-year groups (p for interaction = 0.0006); having been breastfed was significantly associated with a decreased risk among subjects who were born before 1950 (OR = 0.59; 95% CI: 0.35-0.99), whereas no such risk reduction was observed for subjects born after 1950 (OR = 1.60; 95% CI: 0.88-2.90).

CONCLUSION

Although having been breastfed is not related to overall risk, birth year may modify the association between having been breastfed in infancy and breast cancer risk. In Japan, sociodemographic changes have occurred since the end of World War II. The use of standard formula supplement began to spread around 1950. The difference of breast cancer risk between birth-year groups may be attributable to these environmental changes.

Mucinous carcinoma of the breast in comparison with invasive ductal carcinoma: clinicopathologic characteristics and prognosis

Purpose

Mucinous carcinoma (MC) of the breast is a rare histologic type of mammary neoplasm. The objective of this study was to evaluate the long-term disease-free survival (DFS) and overall survival (OS) of MC.

Methods

We conducted a retrospective analysis of all MC cases reported to a database between 1994 and 2010. Clinicopathological characteristics and survival of 268 MC cases were reviewed and compared with 2,455 invasive ductal carcinoma-not otherwise specified (IDC-NOS) cases.

Results

The MC cases were of a younger age, involved less lymph nodes, lower stage, more expression of hormonal receptors, and less HER2 overexpression compared to the IDC-NOS cases. The 5-year DFS rate for MC was 95.2% compared to 92.0% for IDC-NOS. The 5-year OS rate for MC was 98.9% compared to 94.9% for IDC-NOS. Multivariate analysis using Cox regression revealed that the mucinous type was a significant prognostic factor for DFS with lower nodal status (N stage) and hormonal therapy. For OS, only N stage was the most significant prognostic factor followed by adjuvant chemotherapy and adjuvant hormonal therapy.

Conclusion

MC was shown to be associated with a better DFS than IDC-NOS, but it had a similar OS. Nodal status and adjuvant therapy appear to be more significant predictors of prognosis than histologic subtype.

The emerging epidemic of estrogen-related cancers in young women in a developing Asian country

The incidence of breast and genital tract cancers is increasing among Taiwanese women, but the age specificity and histopathological features of these cancers have not been determined. We used a descriptive epidemiological method and data from the Taiwan Cancer Registry (1979-2007) to examine secular trends in the age-specific incidences of female breast cancer, three major female genital tract cancers and the histopathological subtypes of these cancers. Age-specific incidence rates in the United States (1978-2002) were used as an external reference, and the incidence rates of all malignancies and of malignant brain tumors were used as internal references. We found that age-adjusted incidence rates of female breast, uterine, and ovarian cancers increased in Taiwan from 1979 to 2007, whereas the incidence of cervical cancer decreased after 1998. The largest increase was observed for ductal and lobular carcinomas of the breast and endometrioid carcinomas of the uterus and ovary in women ≤55 years, all of these tumors show a high prevalence of hormone receptor expressions. In addition, hormone-receptor-positive rates of breast cancer were uniquely higher in younger, as opposed to older, Taiwanese women. These findings indicate that estrogen-related cancers rapidly emerge in young women in Taiwan and that incidence rates are catching up with that of women living in the United States.

Prognostic significance of young age (<35 years) by subtype based on ER, PR, and HER2 status in breast cancer: a nationwide registry-based study

BACKGROUND

Young age is regarded as an adverse prognostic factor in patients with breast cancer, especially in those with a hormone receptor (HR)-positive tumor. We investigated the prognostic significance of an age of <35 years stratified by molecular subtype based on HR and HER2.

METHODS

Two large databases of Korean breast cancer patients, which included nationwide registry data, were analyzed.

RESULTS

In an analysis of 2,474 patients from the single institution, an age of <35 years was found to be an independent predictor of recurrence in patients with HR+/HER2- (hazard ratio 1.87; 95% confidence interval [CI]: 1.11-3.14; P=0.018), HR+/HER2+ (hazard ratio 3.09; 95% CI: 1.19-8.03; P=0.020), and HR-/HER2+ (hazard ratio 2.01; 95% CI: 1.03-3.92; P=0.040) subtypes, but not in those with the HR-/HER2- (triple-negative, TN) subtype (hazard ratio 1.08; 95% CI: 0.60-1.95; P=0.802). The results of an analysis of nationwide database data on 31,672 patients also showed that an age of <35 years significantly predicted poor cancer-specific survival in patients with HR+/HER2- (hazard ratio 3.40; 95% CI: 2.41-4.82; P<0.001), HR+/HER2+ (hazard ratio 1.96; 95% CI: 1.23-3.12; P=0.005), and HR-/HER2+ (hazard ratio 1.65; 95% CI: 1.07-2.52; P=0.022) subtypes, but again not in those with the TN subtype (hazard ratio 1.21; 95% CI: 0.88-1.67; P=0.240).

CONCLUSION

The prognostic significance of young age was found to depend on molecular subtype. An age of <35 years was a poor prognosticator in patients with the HR+/HER2-, HR+/HER2+, and HR-/HER2+ subtypes, but not in those with the TN subtype.

Breast cancer in Hong Kong, Southern China: the first population-based analysis of epidemiological characteristics, stage-specific, cancer-specific, and disease-free survival in breast cancer patients: 1997-2001

Background

Cancer registries have been set up worldwide to provide information for cancer health planning. There are known variations in breast cancer incidence and mortality worldwide. However, breast cancer incidence, pathological characteristics, and survival data is still under-reported in Asian countries. This is the first comprehensive population-based breast cancer study performed using population database of the Hong Kong Cancer Registry.

Methods

A retrospective review of medical records of 8,961 subjects who were diagnosed with breast cancer between January 1, 1997 to December 31, 2001 and followed up to December 31, 2007. Descriptive statistics were employed to analyze the epidemiological and clinical data. Estimates of overall, disease-free, and cancer-specific survival at 5 years were estimated by the Kaplan–Meier method and stage-specific relative survival rates were calculated.

Results

A total of 7,630 breast cancer patients’ medical records and dataset were available during this period, and 7,449 subjects were eligible for the final analysis. Median follow-up was 84 months. A total of 47.4% were diagnosed with breast cancer at age 49 years and younger; 22.2%, 46.9%, 10.8%, and 4.1% presented at stages I, II, III, and IV, respectively. A total of 53.5% had ER-positive cancer, and 20.3% had HER2-positive cancers; 13.4% had triple-negative cancers. The relative, cancer-specific, and disease-free survival rates at 5 years were 84%, 85.2%, and 81.2%, respectively.

Discussion

We performed the first comprehensive population-based breast cancer epidemiology study in Southern China using the Hong Kong Cancer Registry database. This provides a baseline study cohort for comparative studies with other Asian countries and Chinese who have migrated to the West.

Risk of second cancer after initial treatment of breast cancer: An Osaka Cancer Registry Database study

In the present study, the association between the incidence of second cancer and initial treatment for primary breast cancer was investigated using the Osaka Cancer Registry in Japan. We selected 45,575 patients diagnosed with breast cancer between January 1975 and December 2003. Information on initial cancer treatment and second cancer was obtained from the Osaka Cancer Registry. Patients were classified according to initial treatment (chemo-, hormone, or radiotherapy, or no treatment). We calculated the incidence rate ratio of second cancers in patients classified by treatment for the first cancer. The effects of treatment adjusted for covariates on second cancers were examined using stratified analyses and a Cox proportional hazard model. The final number of 33,043 subjects had a mean duration of follow-up of 5.2±4.3 years, during which 1,857 second cancers were diagnosed. For hormone therapy, the incidence rate ratio (IRR) of all second cancers was 0.64 [95% confidence interval (CI), 0.58-0.70], and that of corpus uteri cancer was 3.04 (95% CI, 1.78-5.19). The multivariate analysis revealed that the IRR of corpus uteri cancer associated with hormone therapy was 2.53 (95% CI, 1.41‑4.55). The incidence rate of all second cancers associated with initial treatment was lower than that associated with no treatment. Only second corpus uteri cancer may be related to hormone therapy.

Trends in invasive breast cancer incidence among French women not exposed to organized mammography screening: an age-period-cohort analysis

BACKGROUND

The long tenure of the Doubs cancer registry (France) and the late implementation of a mass screening program provide a unique opportunity to assess the relative contributions of age, period and cohort effects to the increase in female invasive breast cancer incidence, while avoiding the influence of an organized screening program.

METHODS

Population and incidence data were provided for the Doubs region during the 1978-2003 period. Breast cancer counts and person-years were tabulated into 1-year classes by age and time period. Age-period-cohort models with parametric smooth functions were fitted to the data, assuming a Poisson distribution for the number of observed cases.

RESULTS

A total of 5688 incident cases of invasive breast cancer in women were diagnosed in women aged 30-84 years in the Doubs region between 1978 and 2003. The annual percentage increase in incidence is 2.09%. Age effects rise dramatically until age 50, and at a slower pace afterwards. Large cohort curvature effects (p<10(-6)), show departure from linear trends, with a significant peak for women born around 1940. Period curvature effects are lower in magnitude (p=0.01).

CONCLUSION

Both cohort and period effects are involved in the marked increase in breast cancer incidence over a 25-year period in the Doubs region. Although the future trend for breast cancer incidence is difficult to predict, the introduction of an organized screening program, and the sharp decline in hormone replacement therapy use will likely contribute to period effects in future analyses.