Breast-conserving surgery versus mastectomy in young women with breast cancer in Asian settings

Background

Mastectomy rates among women with early breast cancer in Asia have traditionally been high. This study assessed trends in the surgical management of young women with early‐stage breast cancer in Asian settings. Survival in women treated with breast‐conserving surgery (BCS; lumpectomy with adjuvant radiotherapy) and those undergoing mastectomy was compared.

Methods

Young women (aged less than 50 years) newly diagnosed with stage I or II (T1–2 N0–1 M0) breast cancer in four hospitals in Malaysia, Singapore and Hong Kong in 1990–2012 were included. Overall survival (OS) was compared for patients treated by BCS and those who had a mastectomy. Propensity score analysis was used to account for differences in demographic, tumour and treatment characteristics between the groups.

Results

Some 63·5 per cent of 3536 women underwent mastectomy. Over a 15‐year period, only a modest increase in rates of BCS was observed. Although BCS was significantly associated with favourable prognostic features, OS was not significantly different for BCS and mastectomy; the 5‐year OS rate was 94·9 (95 per cent c.i. 93·5 to 96·3) and 92·9 (91·7 to 94·1) per cent respectively. Inferences remained unchanged following propensity score analysis (hazard ratio for BCS versus mastectomy: 0·81, 95 per cent c.i. 0·64 to 1·03).

Conclusion

The prevalence of young women with breast cancer treated by mastectomy remains high in Asian countries. Patients treated with BCS appear to survive as well as those undergoing mastectomy.

Employment Challenges Faced by Breast Cancer Survivors in an Upper Middle–Income Asian Setting

Background: Cancer survivorship as an area, which focuses on the health and life of an individual following cancer diagnosis and treatment is increasingly being recognized as an important component of the cancer control continuum. Advances in breast cancer detection and treatments have resulted in a growing number of patients experiencing a breast cancer diagnosis at an age when career plays an important role in their lives. Yet, very little is known on how breast cancer affects employment and return to work among survivors, particularly in low- and middle-income settings. Aim: This qualitative study aims to gain an in-depth understanding on employment challenges and motivators/barriers in return to work faced by breast cancer survivors in an upper-middle income Asian setting. Methods: Eleven focus group discussions (FGDs) were conducted with breast cancer survivors representing various ethnicities and socioeconomic backgrounds in Malaysia. Patients diagnosed one to two years prior to the study were recruited from a general public hospital, a public academic hospital and two private hospitals. Data from the FGDs were examined using thematic content analysis from the NVivo software. Results: The major themes relating to impact of cancer diagnosis on employment were “decreased work ability”, “job loss”, “long absenteeism” and “hostile work environment”. Coping strategy themes frequently mentioned to offset income loss from employment changes were “savings”, “part-time work” or financial support from “family/friends” or “social security”. However, participants were quick to highlight the insufficiency and unreliability of these strategies to cope financially in the long run. When describing their decision in choosing to return to work, participants mentioned themes such as “need money”, feeling “more happy” or having a “supportive work environment”. Nonetheless, participants emphasized the “discrimination” they faced in finding a job after active treatment. Specifically, participants' frequent need to take time-off from work for their cancer follow-ups as well as their older age were perceived as disadvantages in seeking employment when compared with younger, healthy applicants. Conclusion: It is evident that a breast cancer diagnosis severely disrupts employment and return to work in middle income settings. Multisectoral interventions are urgently required to improve the employment status of our cancer survivors, including legislative reforms to prevent discrimination. Programs supporting employment and return to work among cancer survivors should be developed and integrated in the provision of a holistic survivorship care.

Serum 25(OH) Vitamin D Deficiency and Risk of Breast Cancer in Malaysia: A Case-Control Study

Background: Despite the emerging literature supporting the beneficial role of sufficient vitamin D level and its association with various cancers, current evidence on the vitamin D and the risk of getting breast cancer is still inconsistent. Furthermore, the study between vitamin D status and breast cancer risk among south east Asian women is limited. Aim: We aimed to investigate the association between vitamin D deficiency and the risk of getting breast cancer among Malaysian women. Methods: We conducted a retrospective nested case control study which consisted of Malaysian Breast Cancer Cohort Study (MyBCC) subjects as the cases and UMMC Mammogram Cohort Study subjects as the hospital control. We also used a secondary data from the Cohort Study on Clustering of Lifestyle Risk Factors and understanding its association with stress on health and well-being among school teachers in Malaysia (CLUSTer), as we only included the data from the schools in Kuala Lumpur as the population control. We measured and compared serum 25-hydroxyvitamin D (25(OH)D) between newly diagnosed breast cancer patients (n= 231), female without cancer who came for mammogram checkup (n= 462) and female teachers without cancer from schools in Kuala Lumpur (n=231). Vitamin D deficiency was defined as serum (25(OH)D) < 50 nmol/L. Results: Median serum (25(OH)D) for cases and controls were 42.43 nmol/L and 44.30 nmol/L, respectively. We examined the association between serum (25(OH)D) and breast cancer risk stratified by age < 50 and ≥ 50 years old. The crude ORs for breast cancer risk in cases and controls did not show statistically significant association with serum (25(OH)D) for both age groups ( P = 0.463 and P = 0.650, respectively). After adjustment for age, ethnicity, education level and BMI the ORs (95% CI) for breast cancer risk among both groups were 1.183 (0.591-2.366) ( P = 0.635) and 1.237 (0.801-1.911) ( P = 0.338) respectively for women with serum (25(OH)D) < 50 nmol/L. Conclusion: Our results suggest that there is lack of association between vitamin D deficiency and the risk of getting breast cancer in Malaysian women.

Low Lifetime Risk of Contralateral Breast Cancer in a Middle-Income Asian Country: Evidence to Guide Post-treatment Surveillance

BACKGROUND

The rate of contralateral risk-reducing mastectomy (CRRM) is increasing in the West with controversial evidence of improved survival in early breast cancer patients. Although uptake of CRRM in Asia appears low, the trends may rise, and there is currently an urgent need to provide evidence for informed decision-making in clinical practice. This study aims to determine the risk of contralateral breast cancer (CBC) and its associated factors in an Asian setting.

METHOD

A total of 2937 newly diagnosed patients with stage I and stage II breast cancer in University Malaya Medical Centre between Jan 1993 to Dec 2012 were included in the study. Multinomial logistic regression analysis allowing death to compete with CBC as a study outcome was used; patients with unilateral breast cancer who were alive were taken as reference. A stepwise backward regression analysis including age at diagnosis, ethnicity, family history of breast cancer, TNM stage, hormonal receptor status, HER2 status, chemotherapy, radiotherapy, and hormone therapy was conducted.

RESULTS

Fifty women developed CBC, over a median follow-up of 6 years. The 5- and 10-year cumulative risk of contralateral breast cancer was 1.0% (95% CI 0.6-1.4%) and 2.8% (95% CI 2.0-3.6%), respectively. Young age at diagnosis of first cancer, positive family history, and stage I disease were independent predictors of CBC.

DISCUSSION

The current study suggests that the risk of CBC is very low in a Southeast Asian setting. Any recommendations or practice of CRRM should be reviewed with caution and patients must be counseled appropriately.

Abstract P2-07-03: Insulin and breast cancer risk: Novel insights from mammographic density analyses

Background: Insulin has been suspected to influence breast cancer risk because of its mitogenic effects and impact on sex hormone levels. Epidemiological studies investigating breast cancer occurrence in insulin-treated patients with diabetes have produced conflicting results, but were often underpowered and lacked adequate control for important confounders.

Purpose: To investigate the impact of insulin treatment on mammographic density (MD) as intermediate phenotype for breast cancer risk, and to further explore causation by analyzing associations with a polygenic risk score (PRS) incorporating 18 single nucleotide polymorphisms (SNPs) associated with fasting insulin levels.

Design: We conducted a matched cohort study within a Swedish screening-based cohort including insulin-treated type 1 (T1D, N=122) and type 2 (T2D, N=237) diabetes patients and up to 5 non-diabetic women matched on birth year (N=1,780). Associations between diabetes status and duration of insulin use with volumetric mammographic density were analyzed using general linear models adjusting for a comprehensive set of potential confounders. PRS analyses were performed in an independent sample of non-diabetic women (N=9,437) from the same cohort.

Results: In multivariable analyses, T1D patients had higher percent (11.2 vs. 8.8%; P&lt;0.001) and absolute dense volumes (66.6 vs. 60.8 cm3; P=0.09) and a lower absolute non-dense volume (513.2 vs. 617.7 cm3; P&lt;0.001) compared to age-matched non-diabetics. Percent- and absolute dense volumes increased with increasing T1D duration, while no such trend was observed for the absolute non-dense volume. Similar associations but of smaller magnitude, were found in insulin-treated T2D patients. Genetically predicted higher fasting insulin levels among non-diabetes women were associated with increased percent and absolute dense volumes (% change per sd increase in PRS = 0.8 (0.0-1.6) and 0.9 (0.1-1.8) respectively), but no difference in absolute non-dense volume.

Conclusions: Our results demonstrate higher mammographic density among insulin-treated diabetes patients, and genetic analyses support an effect of insulin on volumetric mammographic density. Further studies into how the observed MD differences translate into breast cancer risk are warranted.

Citation Format: Borgquist S, Rosendahl AH, Czene K, Bhoo-Pathy N, Dorkhan M, Hall P, Brand JS. Insulin and breast cancer risk: Novel insights from mammographic density analyses [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-07-03.

Roles of Ki67 in Breast Cancer - Important for Management?

BACKGROUND

The three standard biomarkers used in breast cancer are the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). The Ki-67 index, a proliferative marker, has been shown to be associated with a poorer outcome, and despite absence of standardization of pathological assessment, is widely used for therapy decision making. We aim to study the role of the Ki-67 index in a group of Asian women with breast cancer.

MATERIALS AND METHODS

A total of 450 women newly diagnosed with Stage 1 to 3 invasive breast cancer in a single centre from July 2013 to Dec 2014 were included in this study. Univariable and multivariable logistic regression was used to determine the association between Ki-67 (positive defined as 14% and above) and age, ethnicity, grade, mitotic index, ER, PR, HER2, lymph node status and size. All analyses were performed using SPSS Version 22.

RESULTS

In univariable analysis, Ki -67 index was associated with younger age, higher grade, ER and PR negativity, HER2 positivity, high mitotic index and positive lymph nodes. However on multivariable analysis only tumour size, grade, PR and HER2 remained significant. Out of 102 stage 1 patients who had ER positive/PR positive/HER2 negative tumours and non-grade 3, only 5 (4.9%) had a positive Ki-67 index and may have been offered chemotherapy. However, it is interesting to note that none of these patients received chemotherapy.

CONCLUSIONS

Information on Ki67 would have potentially changed management in an insignificant proportion of patients with stage 1 breast cancer.

The value of adjuvant radiotherapy on survival and recurrence in triple-negative breast cancer: A systematic review and meta-analysis of 5507 patients

BACKGROUND

The value of adjuvant radiotherapy in triple negative breast cancer (TNBC) remains unclear. A systematic review and meta-analysis was conducted in TNBC patients to assess survival and recurrence outcomes associated with radiotherapy following either breast conserving therapy (BCT) or post-mastectomy radiotherapy (PMRT).

METHODS

Four electronic databases were searched from January 2000 to November 2015 (PubMed, MEDLINE, EMBASE and Web of Science). Studies investigating overall survival and/or recurrence in TNBC patients according to radiotherapy administration were included. A random effects meta-analysis was conducted using mastectomy only patients as the reference.

RESULTS

Twelve studies were included. The pooled hazard ratio (HR) for locoregional recurrence comparing BCT and PMRT to mastectomy only was 0.61 (95% confidence interval [CI] 0.41-0.90) and 0.62 (95% CI 0.44-0.86), respectively. Adjuvant radiotherapy was not significantly associated with distant recurrence. The pooled HR for overall survival comparing BCT and PMRT to mastectomy only was 0.57 (95% CI 0.36-0.88) and HR 1.12 (95% CI 0.75, 1.69). Comparing PMRT to mastectomy only, tests for interaction were not significant for stage (p=0.98) or age at diagnosis (p=0.85). However, overall survival was improved in patients with late-stage disease (T3-4, N2-3) pooled HR 0.53 (95% CI 0.32-0.86), and women <40years, pooled HR 0.30 (95% CI 0.11-0.82).

CONCLUSIONS

Adjuvant radiotherapy was associated with a significantly lower risk of locoregional recurrence in TNBC patients, irrespective of the type of surgery. While radiotherapy was not consistently associated with an overall survival gain, benefits may be obtained in women with late-stage disease and younger patients.

Breast Cancer Outcomes as Defined by the Estrogen Receptor, Progesterone Receptor, and Human Growth Factor Receptor-2 in a Multi-ethnic Asian Country

INTRODUCTION

Breast cancer can be divided into four subtypes based on the expressions of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor-2 (HER2). Each subtype has different clinicopathological features and outcomes.

OBJECTIVE

To compare the clinicopathological features and survival of ER and/or PR positive HER2 negative (ER+PR+HER2-, ER+PR-HER2- or ER-PR+HER2-), ER and/or PR positive HER2 positive (ER+PR+HER2+, ER+PR-HER2+ or ER-PR+HER2+), ER negative PR negative HER2 positive (ER-PR-HER2+), and ER negative PR negative HER2 negative (ER-PR-HER2-) subtypes.

METHODS

1957 patients with Stage 1-3 breast carcinoma diagnosed between Jan 2005 and Dec 2011 were categorized into the four subtypes. The clinicopathological features between the subtypes were compared using χ (2) test. Kaplan-Meier analysis was performed to estimate 5-year overall survival. Multivariate Cox regression was used to determine the association between subtypes and mortality adjusted for age, ethnicity, stage, pathological features, and treatment.

RESULTS

ER-PR-HER2+ and ER-PR-HER2- subtypes were associated with younger age, larger tumors, and higher grade. There was no difference in the 5-year survival of the ER-PR-HER2+ and ER-PR-HER2- subtypes (75.1 and 74.4 %, respectively) and survival was poorer than in the ER and/or PR positive HER2 negative and ER and/or PR positive HER2 positive subtypes (87.1 and 83.1 %, respectively). Only 9.5 % of women with HER2 positive breast cancer had access to trastuzumab.

CONCLUSION

In a low resource setting with limited access to trastuzumab, there is no difference in survival between the ER-PR-HER2+ and ER-PR-HER2- subtypes of breast cancer.

Prediction of lymph node involvement in patients with breast tumors measuring 3-5 cm in a middle-income setting: the role of CancerMath

BACKGROUND

In settings with limited resources, sentinel lymph node biopsy (SNB) is only offered to breast cancer patients with small tumors and a low a priori risk of axillary metastases.

OBJECTIVE

We investigated whether CancerMath, a free online prediction tool for axillary lymph node involvement, is able to identify women at low risk of axillary lymph node metastases in Malaysian women with 3-5 cm tumors, with the aim to offer SNB in a targeted, cost-effective way.

METHODS

Women with non-metastatic breast cancers, measuring 3-5 cm were identified within the University Malaya Medical Centre (UMMC) breast cancer registry. We compared CancerMath-predicted probabilities of lymph node involvement between women with versus without lymph node metastases. The discriminative performance of CancerMath was tested using receiver operating characteristic (ROC) analysis.

RESULTS

Out of 1,017 patients, 520 (51 %) had axillary involvement. Tumors of women with axillary involvement were more often estrogen-receptor positive, progesterone-receptor positive, and human epidermal growth factor receptor (HER)-2 positive. The mean CancerMath score was higher in women with axillary involvement than in those without (53.5 vs. 51.3, p = 0.001). In terms of discrimination, CancerMath performed poorly, with an area under the ROC curve of 0.553 (95 % confidence interval CI 0.518-0.588). Attempts to optimize the CancerMath model by adding ethnicity and HER2 to the model did not improve discriminatory performance.

CONCLUSION

For Malaysian women with tumors measuring 3-5 cm, CancerMath is unable to accurately predict lymph node involvement and is therefore not helpful in the identification of women at low risk of node-positive disease who could benefit from SNB.

Spectrum of very early breast cancer in a setting without organised screening

BACKGROUND

Within a setting without organised breast cancer screening, the characteristics and survival of very early breast cancer were determined.

METHODS

All 4930 women diagnosed with breast cancer in University Malaya Medical Center, Malaysia from 1993 to 2011 were included. Factors associated with very early presentation (stage I) at diagnosis were identified. Tumour characteristics, management patterns, and survival of very early breast cancer were described, and where appropriate, compared with other settings.

RESULTS

Proportion of women presenting with stage I breast cancer significantly increased from 15.2% to 25.2% over two decades. Factors associated with very early presentation were Chinese ethnicity, positive family history of breast cancer, and recent period of diagnosis. Within stage I breast cancers, median tumour size at presentation was 1.5 cm. A majority of stage I breast cancer patients received mastectomy, which was associated with older age, Chinese ethnicity, postmenopausal status, and larger tumours. Chemotherapy was administered in 36% of patients. Five-year age-adjusted relative survival for women with stage I breast cancer was 99.1% (95% CI: 97.6-99.6%).

CONCLUSIONS

The proportion of women presenting with very early breast cancer in this setting without organised screening is increasing. These women seem to survive just as well as their counterparts from affluent settings.

Abstract P6-06-16: Young age as a good prognostic factor in de novo metastatic breast cancer

Background

While breast cancer is relatively rare in young women under the age of 40, its incidence is increasing and accounts for up to 40% of all female cancers. Young age at diagnosis is associated with a poorer prognosis in early breast cancers; however little is known about the natural history of young women with metastatic breast cancer. We aim to evaluate the effect of age on breast-cancer specific survival (BCS) and overall survival (OS) for patients with de novo metastatic breast cancer using data from the SEER registry.

Methods

We retrospectively analyzed 14155 patients with de novo metastatic breast cancer from the SEER registry between 2000 and 2009. Young women were defined as 50 years and below and further subdivided into three groups: 20-34, 35-39, and 40-49 years. Age 50-69 years served as a comparison group. Unadjusted overall survival (OS) and breast cancer specific survival (BCS) were accessed using Kaplan-Meier plots and compared across groups using log-rank tests. Cox proportional hazards models were then fitted to determine the association between survival end point and age after adjusting for patient and tumor characteristics.

Results

546 (3.9%) patients were age 20-34 years, 750 (5.3%) were 35-39 years, 3049 (21.5%) were 40-49 years and 9810 (69.3%) patients were 50-69 years. Median BCS among patients age 20-34, 35-39, 40-49 and 50-69 years was 30, 33, 35, 28 months respectively (P&lt;0.0001). Median BCS among patients with estrogen receptor positive disease who were age 20-34, 35-39, 40-49 and 50-69 years was 43, 42, 51, 37 months respectively (P&lt;0.0001). Similarly median BCS among patients with estrogen receptor negative disease who were age 20-34, 35-39, 40-49 and 50-69 years was 21, 18, 18, 17 months respectively (P&lt;0.0001). In the multivariable model compared to patients who were age 50 -69 years those aged 20-34 years (HR 0.88, 95% CI 0.78-0.99), 35-39 years (HR 0.82, 95% CI 0.74-0.91) and 40-49 years (HR 0.84, 95% CI 0.79-0.89) had a significantly decreased risk of death from breast cancer. Similar results were obtained for OS.

Conclusion

Younger patients defined by age less than 50 years had a better BCS and OS when compared against older age group in the setting of de novo metastatic breast cancer. This may be explained by lack of important comorbidities, relatively good performance status as well as ability to tolerate more lines of chemotherapies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-16.

Abstract P6-06-28: Survival gain in patients with de novo metastatic breast cancer in past two decades is largely attributable to treatment

Background: In Asia, a substantial proportion of breast cancer patients present with distant metastases at diagnosis. We determined whether metastatic breast cancer survival has improved in a multi-ethnic Asian setting over a span of fifteen years, and disentangled the contribution of various factors on the observed survival trend.

Methods: Patients diagnosed with de novo metastatic breast cancer from three hospitals in Malaysia and Singapore (N = 856) were assigned to three cohorts by year of diagnosis: 1996-2000, 2001-2005 and 2006-2010. Time trends in disease characteristics, treatment, and relative survival rates (RSR) were compared. Adjusted relative excess risks of mortality in recent periods were estimated using a step-wise Poisson regression to assess the contributions of several prognostic factors towards the observed survival pattern.

Results: The proportion of patients presenting with de novo metastatic breast cancer remained fairly stable at 10% in 1996-2000, 7% in 2001-2005, and 9% in 2006 -2010. Recently diagnosed patients were older, and more likely to have multiple metastatic sites involved, and visceral metastases. Surgery of primary tumor became more prevalent over time, and this is also complemented with higher attainments of free surgical margins. Chemotherapy, and endocrine therapy administration also increased with time, with higher use of taxane-based regimens in recent periods. The three-year RSR in the above periods were 20.6% (95%CI: 13.9%-28.2%, median survival = 14 months), 28.8% (95%CI: 23.4%-34.2%, median survival = 18 months), and 33.6% (95%CI: 28.8%-38.5%, median survival = 21 months), respectively. Surgery of the primary tumor explained most of the observed survival gain in the latest period, followed by chemotherapy, and endocrine therapy.

Excess Mortality Risk in Patients with De Novo Metastatic Breast Cancer by Period of Diagnosis Period of diagnosisDeath1996-200012001-20052006-2010Relative excess risk (95%CI)21.000.86(0.68-1.09)0.68(0.54-0.86)7Relative excess risk (95%CI)31.000.82 (0.65-1.05)0.68(0.54-0.87)7Relative excess risk (95%CI)41.000.82 (0.64-1.05)0.66(0.52-0.84)7Relative excess risk (95%CI)51.000.89 (0.69-1.15)0.76(0.59-0.97)7Relative excess risk (95%CI)61.000.89 (0.69-1.16)0.79(0.62-1.01)1 Reference period, 2 Derived using Poisson regression model, matched to background population mortality based on country, year, and age, and adjusted for center, and follow-up time, 3 Similar as model 2, and additionally adjusted for age at diagnosis, and ethnicity, 4 Similar as model 3, and additionally adjusted for T stage at diagnosis, ER status, number of organs with metastatic involvement, and presence of visceral metastasis, 5 Similar as model 4, and additionally adjusted for surgery, and surgical margins, 6 Similar as model 5, and additionally adjusted for radiotherapy, chemotherapy, and endocrine therapy, 7 Statistically significant

Conclusion: The modest survival gain in patients with de novo metastatic breast cancer in Asian settings is largely attributable to improvement in treatment strategies, namely surgery of primary tumor and other treatment modalities.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-28.