Assessment of the Androgen Receptor in Older Women with Primary Breast Cancer: Association with a Panel of Biomarkers and Breast Cancer Specific Survival

INTRODUCTION

Breast cancer in older women tends to have more favourable biology, compared to younger women. Androgen receptor (AR) is significant for breast tumour carcinogenesis; however, the role of AR in older women has not been fully explored.

METHODS

Surgical specimens were obtained from an existing series of 1758 older women (≥ 70 years) with primary breast cancer, treated in a single institution with long-term (≥ 37 years) follow-up. As part of previous work, it was possible to construct good quality tissue microarrays (TMAs) in 575 surgical specimens and a panel of 24 biomarkers was measured by immunohistochemistry (IHC) in these TMAs. AR positivity was assessed by IHC and defined as H-score ≥ 40. The relationship between AR in this cohort was compared to an equivalent group of younger women (< 70 years, n = 1708); the panel of 24 biomarkers and breast cancer specific survival (BCSS) in the older cohort.

RESULTS

AR was assessed in 509 samples. Overall, 59% of the older women cohort had positive expression of AR, compared to 63% in the younger cohort. AR positivity (regardless of age) was associated with smaller size of tumour, lower grade of tumour, lower tubule formation, lower nuclear polymorphism and lower mitotic frequency. AR positivity was associated with positive expression of oestrogen receptor (ER), progesterone receptor (PR), breast cancer gene 1 (BRCA1), cytokeratin (CK) 7/8, CK18, CK19, B cell lymphoma (Bcl)2 and Mucin 1 (Muc1) expression. Conversely, AR-positive expression was associated with negative expression of human epidermal growth factor receptor 2 (HER2), Ki-67, CK5, CK17, epidermal growth factor receptor (EGFR), and CD44 expression. Older women with AR-positive tumours had better BCSS compared to AR-negative tumours (p = 0.009).

CONCLUSIONS

There was no difference in AR expression between older and younger women with breast cancer. AR has prognostic potential in terms of BCSS. Further work is needed to investigate AR as a therapeutic target.

Age-Related Biology of Early-Stage Operable Breast Cancer and Its Impact on Clinical Outcome

Simple Summary

Breast cancer incidence not only increases with advancing age but also changes its biology. This study was conducted to understand aging related change in the biological characteristics of breast cancer. The results highlighted that the change occurs in a gradual fashion, where 40 years and 70 years become the milestones for significant difference. Breast cancer in patients <40 years showed aggressive characteristics while at 70 years and above they are more indolent. The molecular pattern between 40 years and 70 years appears to be a transition from aggressive to less aggressive phenotypes. This change in the biology of the breast cancer significantly influences clinical outcome.

Abstract

As age advances, breast cancer (BC) tends to change its biological characteristics. This study aimed to explore the natural progression of such changes. The study included 2383 women with clinically T0-2N0-1M0 BC, managed by primary surgery and optimal adjuvant therapy in a dedicated BC facility. Tissue micro-arrays were constructed from their surgical specimens and indirect immunohistochemistry was used for analysis of a large panel (n = 16) of relevant biomarkers. There were significant changes in the pattern of expression of biomarkers related to luminal (oestrogen receptor (ER), progesterone receptors (PgR), human epidermal growth factor receptor (HER-2), E-cadherin, MUC1, bcl2 CK7/8, CK18 and bcl2) and basal (CK5/6, CK14, p53 and Ki67) phenotypes, lymph node stage, histological grade and pathological size when decade-wise comparison was made (p < 0.05). The ages of 40 years and 70 years appeared to be the milestones marking a change of the pattern. There were significantly higher metastasis free and breast cancer specific survival rates among older women with ER positive tumours while there was no significant difference in the ER negative group according to age. Biological characteristics of BC show a pattern of change with advancing age, where 40 years and 70 years appear as important milestones. The pattern suggests <40 years as the phase with aggressive phenotypes, >70 years as the less aggressive phase and 40–70 years being the transitional phase.

Patterns of biomarker expression in patients treated with primary endocrine therapy - a unique insight using core needle biopsy tissue microarray

Purpose

Prediction of response to primary endocrine therapy (PET) in older women is based on measurement of oestrogen receptor (ER), progesterone receptor (PgR) and human epidermal growth factor (HER)-2. This study uses a unique method for construction of core needle biopsy (CNB) tissue microarray (TMA), to correlate expression of a panel of 17 biomarkers with clinical outcome, in patients receiving PET.

Methods

Over 37 years (1973–2010), 1758 older (≥ 70 years) women with operable primary breast cancer were managed in a single institution. Of these, 693 had sufficient good-quality CNB to construct TMA, of which 334 had ER-positive tumours treated by PET with a minimum of 6-month follow-up. A panel of biomarkers was measured by immunohistochemistry (ER, PgR, HER2, Ki-67, p53, CK5/6, CK 7/8, EGFR, BCL-2, MUC1, VEGF, LKB1, BRCA1, HER3, HER4, PTEN and AIB1). Expression of each biomarker was dichotomised into ‘low’ or ‘high’ based on breast cancer-specific survival (BCSS).

Results

From the panel of biomarkers, multivariate analysis showed:

High ER (p = 0.003) and PgR (p = 0.002) were associated with clinical benefit of PET at 6 months, as opposed to progressive disease.

High ER (p = 0.0023), PgR (p < 0.001) and BCL-2 (p = 0.043) and low LKB1 (p = 0.022) were associated with longer time to progression.

High PgR (p < 0.001) and low MUC1 (p = 0.021) were associated with better BCSS.

Expression of other biomarkers did not show any significant correlation.

Conclusions

In addition to ER and PgR; MUC1, BCL-2 and LKB1 are important in determining the outcome of PET in this cohort.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-06023-4) contains supplementary material, which is available to authorised users.

Biology of Oestrogen-Receptor Positive Primary Breast Cancer in Older Women with Utilisation of Core Needle Biopsy Samples and Correlation with Clinical Outcome

The majority of biological profiling studies use surgical excision (SE) samples, excluding patients receiving nonsurgical and neoadjuvant therapy. We propose using core needle biopsy (CNB) for biological profiling in older women. Over 37 years (1973–2010), 1 758 older (≥70 years) women with operable primary breast cancer attended a dedicated clinic. Of these, 693 had sufficient quality CNB to construct tissue microarray (TMA). The pattern of biomarkers was analysed in oestrogen receptor (ER)-positive cases, using immunohistochemistry and partitional clustering analysis. The biomarkers measured were: progesterone receptor (PgR), Ki67, Epidermal Growth Factor Receptor (EGFR), Human Epidermal Growth Factor Receptor (HER)-2, HER3, HER4, p53, cytokeratins CK5/6 and CK7/8, Mucin (MUC)1, liver kinase B1 (LKB1), Breast Cancer Associated gene (BRCA) 1, B-Cell Lymphoma (BCL)-2, phosphate and tensin homolog (PTEN), vascular endothelial growth factor (VEGF), and Amplified in breast cancer 1 (AIB1). CNB TMA construction was possible in 536 ER-positive cases. Multivariate analysis showed progesterone receptor (PgR) (p = 0.015), Ki67 (p = 0.001), and mucin (MUC)1 (p = 0.033) as independent predictors for breast-cancer-specific survival (BCSS). Cluster analysis revealed three biological clusters, which were consistent with luminal A, luminal B, and low-ER luminal. The low-ER luminal cluster had lower BCSS compared to luminal A and B. The presence of the low-ER luminal cluster unique to older women, identified in a previous study in SE TMAs in the same cohort, is confirmed. This present study is novel in its use of core needle biopsy tissue microarrays to profile the biology of breast cancer in older women.

Cytoplasmic Cyclin E Is an Independent Marker of Aggressive Tumor Biology and Breast Cancer-Specific Mortality in Women over 70 Years of Age

Multi-cohort analysis demonstrated that cytoplasmic cyclin E expression in primary breast tumors predicts aggressive disease. However, compared to their younger counterparts, older patients have favorable tumor biology and are less likely to die of breast cancer. Biomarkers therefore require interpretation in this specific context. Here, we assess data on cytoplasmic cyclin E from a UK cohort of older women alongside a panel of >20 biomarkers. Between 1973 and 2010, 813 women ≥70 years of age underwent initial surgery for early breast cancer, from which a tissue microarray was constructed (n = 517). Biomarker expression was assessed by immunohistochemistry. Multivariate analysis of breast cancer-specific survival was performed using Cox's proportional hazards. We found that cytoplasmic cyclin E was the only biological factor independently predictive of breast cancer-specific survival in this cohort of older women (hazard ratio (HR) = 6.23, 95% confidence interval (CI) = 1.93-20.14; p = 0.002). At ten years, 42% of older patients with cytoplasmic cyclin E-positive tumors had died of breast cancer versus 8% of negative cases (p < 0.0005). We conclude that cytoplasmic cyclin E is an exquisite marker of aggressive tumor biology in older women. Patients with cytoplasmic cyclin E-negative tumors are unlikely to die of breast cancer. These data have the potential to influence treatment strategy in older patients.

Multidisciplinary care of breast cancer patients: a scoping review of multidisciplinary styles, processes, and outcomes

Background

Clinical practice guidelines recommend a multidisciplinary approach to cancer care that brings together all relevant disciplines to discuss optimal disease management. However, the literature is characterized by heterogeneous definitions and few reviews about the processes and outcomes of multidisciplinary care. The objective of this scoping review was to identify and classify the definitions and characteristics of multidisciplinary care, as well as outcomes and interventions for patients with breast cancer.

Methods

A systematic search for quantitative and qualitative studies about multidisciplinary care for patients with breast cancer was conducted for January 2001 to December 2017 in the following electronic databases: medline, embase, PsycInfo, and cinahl. Two reviewers independently applied our eligibility criteria at level 1 (title/abstract) and level 2 (full-text) screening. Data were extracted and synthesized descriptively.

Results

The search yielded 9537 unique results, of which 191 were included in the final analysis. Two main types of multidisciplinary care were identified: conferences and clinics. Most studies focused on outcomes of multidisciplinary care that could be variously grouped at the patient, provider, and system levels. Research into processes tended to focus on processes that facilitate implementation: team-working, meeting logistics, infrastructure, quality audit, and barriers and facilitators.

Summary

Approaches to multidisciplinary care using conferences and clinics are well described. However, studies vary by design, clinical context, patient population, and study outcome. The heterogeneity of the literature, including the patient populations studied, warrants further specification of multidisciplinary care practice and systematic reviews of the processes or contexts that make the implementation and operation of multidisciplinary care effective.

Liver Kinase B1-A Potential Therapeutic Target in Hormone-Sensitive Breast Cancer in Older Women

Background: The role of liver kinase B1 (LKB1), a serine/threonine kinase, has been described in the development of PeutzJagher’s syndrome, where a proportion (~45%) of patients have developed breast cancer in their lifetime. Cell line studies have linked LKB1 with oestrogen receptors (ER) and with the Adenosine monophosphate-activated protein kinase (AMPK) pathway for energy metabolism. However, limited studies have investigated protein expression of LKB1 in tumour tissues and its intracellular relationships. This study aimed to investigate the intracellular molecular relationships of LKB1 in older women with early operable primary breast cancer and its correlation with long-term clinical outcome. Methods: Between 1973 and 2010, a consecutive series of 1758 older (≥70 years) women with T0-2N0-1M0 breast carcinoma were managed in a dedicated facility. Of these, 813 patients underwent primary surgery, and 575 had good quality tumour samples available for tissue microarray construction. LKB1 was assessed in 407 cases by indirect immunohistochemistry (IHC). Tumours with 30% or more of cells with cytoplasmic LKB1 expression were considered positive. LKB1 expression was compared with tumour size, histological grade, axillary lymph node stage, ER, PgR, EGFR, HER2, HER3, HER4, BRCA1&2, p53, Ki67, Bcl2, Muc1, E-Cadherin, CD44, basal (CK5, CK5/6, CK14 and CK17) and luminal (CK7/8, CK18 and CK19) cytokeratins, MDM2 and MDM4, and correlated with long-term clinical outcome. Results: Positive LKB1 expression was seen in 318 (78.1%) patients, and was significantly associated with high tumour grade, high Ki67, over-expression of HER2, VEGF, HER4, BRCA2, MDM2 and negative expression of CD44 (p < 0.05). There was no significant correlation with tumour size, axillary lymph node status, ER, PgR, p53, basal or luminal cytokeratins, Bcl2, Muc1, EGFR, HER3, MDM4, E-cadherin and BRCA1. LKB1 did not show any significant influence on survival in the overall population; however, in those patients receiving adjuvant endocrine therapy for ER positive tumours, those with positive LKB1 had significantly better 5-year breast cancer specific survival when compared to those without such expression (93% versus 74%, p = 0.03). Conclusion: LKB1 expression has shown association with poor prognostic factors in older women with breast cancer. However, LKB1 expression appears to be associated with better survival outcome among those patients receiving adjuvant endocrine therapy. Further research is required to explore its potential role as a therapeutic target.

A Continuing Mission to Optimize the Care of Older Women with Breast Cancer

The majority of cases of breast cancer occur in the older population who are often un-represented in clinical trials. Given the growing ageing population globally, it becomes urgent and important to identify an optimal approach so that older women with breast cancer are neither under- or over-treated. An inter-disciplinary research program is ongoing to investigate differing tumor biology according to age, and the potential use of a geriatric assessment tool, aiming to help select older women with primary breast cancer for a personalized and optimal treatment. Full considerations of the biology of the patient’s cancer and the geriatric domains of the patient must be taken into account when making treatment decisions.

Breast cancer in elderly women and altered clinico-pathological characteristics: a systematic review

PURPOSE

Breast cancer is the most common malignancy in women in terms of incidence and mortality. Age is undoubtedly the biggest breast cancer risk factor. In this study we examined clinical, histological, and biological characteristics and mortality of breast cancer in elderly women along with their changes with advancing age.

METHODS

We reviewed 63 original articles published between 2006 and 2016 concerning women over 70 years with breast cancer.

RESULTS

Compared to patients 70-79 years, patients aged 80 and over had larger tumor size with fewer T1 (42.9% vs 57.7%, p < 0.01) and more T2 lesions (43.5% vs 33.0%, p < 0.01). Lymph nodes and distant metastases were more frequent, with more N + (49.5% vs 44.0%, p < 0.01) and more M1 (8.0% vs 5.9%, p < 0.01). Infiltrating mucinous carcinomas were more frequent (4.3% vs 3.7%, p < 0.01). Tumors had lower grades, with more grade 1 (23.2% vs 19.8%, p = 0.01) and fewer grade 3 (21.5% vs 25.5%, p < 0.01), and were more hormone-sensitive: PR was more often expressed (72.6% vs 67.3%, p < 0.01). Lympho-vascular invasion was less frequent in the 80 years and over (22.9% vs 29.7%, p = 0.01). Breast cancer-specific mortality was higher both at 5 years (25.8% vs 17.2%, p < 0.01) and 10 years (32.7% vs 26.6%, p < 0.01).

CONCLUSION

Clinico-pathological characteristics, increased incidence, and mortality associated with aging can be explained on one hand by biological changes of the breast such as increased estrogen sensitivity, epithelial cell alterations, immune senescence, and tumor microenvironment modifications. However, sociologic factors such as increased life expectancy, under-treatment, late diagnosis, and insufficient individual screening, are also involved.

What happens when we do not operate? Survival following conservative bowel cancer management

Introduction While surgery is the cornerstone of bowel cancer treatment, it comes with significant risks. Among patients aged over 80 years, 30-day mortality is 13%-15%, and additionally 12% will not return home and go on to live in supportive care. The question for patients and clinicians is whether operative surgery benefits elderly, frail patients. Methods Multidisciplinary team outcomes between October 2010 and April 2012 were searched to conduct a retrospective analysis of patients with known localised colorectal cancer who did not undergo surgery due to being deemed unfit. Results Twenty six patients survived for more than a few weeks following surgery, of whom 20% survived for at least 36 months. The average life expectancy following diagnosis was 1 year and 176 days, with a mean age at diagnosis of 87 years (range 77-93 years). One patient survived for 3 years and 240 days after diagnosis. Conclusions Although surgeons are naturally focused on surgical outcomes, non-operative outcomes are equally as important for patients. Elderly, frail patients benefit less from surgery for bowel cancer and have higher risks than younger cohorts, and this needs to be carefully discussed when jointly making the decision whether or not to operate.

The decision-making process for senior cancer patients: treatment allocation of older women with operable breast cancer in the UK

Objective

Up to 40% of women over 70 years with primary operable breast cancer in the UK are treated with primary endocrine therapy (PET) as an alternative to surgery. A variety of factors are important in determining treatment for older breast cancer patients. This study aimed to identify the patient and tumor factors associated with treatment allocation in this population.

Methods

Prospectively collected data on treatment received (surgery vs. PET) were analysed with multivariable logistic regression using the variables age, modified Charlson Comorbidity Index (CCI), activities of daily living (ADL) score, Mini-Mental State Examination (MMSE) score, HER2 status, tumour size, grade and nodal status.

Results

Data were available for 1,122 cancers in 1,098 patients recruited between February 2013 and June 2015 from 51 UK hospitals. About 78% of the population were treated surgically, with the remainder being treated with PET. Increasing patient age at diagnosis, increasing CCI score, large tumor size (5 cm or more) and dependence in one or more ADL categories were all strongly associated with non-surgical treatment (P<0.05).

Conclusion

Increasing comorbidity, large tumor size and reduced functional ability are associated with reduced likelihood of surgical treatment of breast cancer in older patients. However, age itself remains a significant factor for non-surgical treatment; reinforcing the need for evidence-based guidelines.

The role of primary endocrine therapy in older women with operable breast cancer

ABSTRACT 

A Cochrane review of randomized trials shows no difference in overall survival between surgery and primary endocrine therapy (PET) in older women with operable primary breast cancer. Most of these trials were small and unselected for estrogen receptor (ER) status. Evidence exists showing a significant correlation between the degree of ER-positivity and response and outcome in patients receiving PET. Although surgery remains the treatment of choice, patients with ER-rich tumors tend to do equally well on PET. When deciding optimal therapies, co-morbidities and frailty (which impact on the likelihood of death due to competing causes), patient choice, agent of choice (notably the third-generation aromatase inhibitors) and biology (more than just being ER-positive) should all be taken into account.

Update of the Phase III trial 'GRETA' of surgery and tamoxifen versus tamoxifen alone for early breast cancer in elderly women

BACKGROUND

In the Phase III 'GRETA' trial 474 women aged ≥70 years with early breast cancer were randomly assigned to surgery plus tamoxifen for 5 years or tamoxifen alone for 5 years. This is a long-term update.

PATIENTS & METHODS

Focusing on patients still alive in 2003, outcome end points has been recalculated.

RESULTS

Median distant metastases disease-free survival is longer with tamoxifen alone for 5 years; (48.8 vs 37.9 months; p = 0.009). No difference was found in distant metastases rate, disease-free survival, breast cancer and overall survival.

CONCLUSION

Primary endocrine treatment until the the best response, followed by minimal surgery and prosecution endocrine treatment for 5-10 years is a suitable option for elderly breast cancer patients. Delayed surgery does not prejudice overall survival.

Management of operable primary breast cancer in older women

A considerable number of breast cancer diagnoses are made in older women. Differing physiological needs of older patients and biology of tumors compared with younger patients may alter treatment options between surgery and nonsurgical primary approaches. Adjuvant therapies may benefit these patients; however, concerns about toxicity and physical demands of treatment may affect patient choice regarding treatment. Furthermore, quality of life may be more important to the older individual than curative treatment alone. Growing evidence is emerging for employing Comprehensive Geriatric Assessment to determine other factors that may contribute to treatment decision-making in the older population. The way geriatric oncology is delivered varies, bringing the importance of the multidisciplinary team to the forefront of care delivery in this age group. Future research in this area should include combined consideration of tumor biology and geriatric needs.

A study of ductal versus non-ductal invasive breast carcinomas in older women: long-term clinical outcome and comparison with their younger counterparts

Ductal carcinoma is the commonest histological type found in invasive breast carcinomas and may be associated with worse prognosis, when compared to non-ductal carcinoma. Older patients tend to display more favourable tumour biology than younger patients. This study aimed to investigate the significance of histological type and its relationship with clinical outcome in the older group. A total of 808 older (≥70 years) women with early operable primary breast cancer underwent surgery as their primary treatment, followed by optimal adjuvant therapies, in the Nottingham Breast Unit between 1973 and 2009. The histological types of the surgical specimens were reviewed and compared with those in a previously characterised younger (<70 years) series (N = 1,733), in terms of distribution and correlation with clinical outcome. Ductal type was associated with a significantly worse clinical outcome when compared to non-ductal type in the older group in terms of 10-year rates of metastasis-free survival (75 vs 79 %, p = 0.028) and overall survival (44 vs 52 %; p = 0.015). Similar worse clinical outcome was found with the ductal type in the younger group in terms of 10-year rates of metastasis-free survival (65 vs 79 %; p = 0.001) and overall survival (60 vs 78 %; p = 0.001). For all patients with ductal type carcinomas, the older series showed significantly better 10-year metastasis-free survival (75 vs 65 %, p < 0.001) and breast cancer-specific survival (75 vs 69 %, p = 0.025) when compared to the younger series. In both old and the young, ductal cancers were associated with poor survival outcome when compared to non-ductal cancers. When compared to their younger counterparts, older patients with ductal type carcinomas had better metastasis-free and breast cancer-specific survival rates (their lower overall survival was likely to be due to death from other causes), despite having a lower likelihood of receiving adjuvant systemic therapy.

Biological characteristics and clinical outcome of triple negative primary breast cancer in older women - comparison with their younger counterparts

Triple negative (ER, PgR and HER2 negative) breast cancers (TNBCs) are often considered as a poor prognostic phenotype. There is dearth of evidence showing the prevalence and biological behaviour of TNBCs in older women. This study aimed to analyse their biological characteristics in comparison with a well characterised younger series from a single centre with long term clinical follow-up. Over 37 years (1973-2010), 1,758 older (≥70 years) women with early operable (<5 cm) primary breast cancer were managed in a dedicated clinic and have complete clinical information available. Of these 813 patients underwent primary surgery and 575 had good quality tumour samples available for tissue microarray analysis using indirect immunohistochemistry. A total of 127 patients (22.1%) had TNBCs and full biological analysis of 15 biomarkers was performed. The results were compared with those of their younger (<70 years) counterparts 342 (18.9%) from a previously characterised, consecutive series of primary breast cancer treated in the same unit (1986-1998). The 127 older patients with TNBCs showed lower rates of Ki67 and CK 7/8 positivity and high rates of bcl2 and CK18 positivity when compared with their younger counterparts (p<0.05). There was no significant difference in the long term clinical outcome between the two age groups, despite the fact that 47% of the younger patients had adjuvant chemotherapy, while none in the older cohort received such treatment. EGFR, axillary stage and pathological size showed prognostic significance in older women with TNBCs on univariate analysis. Despite not having received adjuvant chemotherapy, the older series had clinical outcome similar to the younger patients almost half of whom had chemotherapy. This appears to be related to other biomarkers (in addition to ER/PgR/HER2) eg Ki67, bcl2 and cytokeratins which have different expression patterns influencing prognosis.

Human epidermal growth receptor-2 overexpressing early operable primary breast cancers in older (≥70 years) women: biology and clinical outcome in comparison with younger (<70 years) patients

INTRODUCTION

There is dearth of literature reporting the prevalence and biological characteristics as well as the long-term clinical outcome of human epidermal growth factor receptor-2 (HER2) overexpressing tumours in older women. Currently, research involving trastuzumab at large focuses on the younger population. This study aimed to analyse their biological characteristics and to compare them with their younger counterparts from a single centre with a long-term clinical follow-up.

METHODS

Over 37 years (1973-2010), 1758 older (≥70 years) women with early operable (<5 cm) primary breast cancer were managed in a dedicated clinic and have complete clinical information available. Of these, 813 patients underwent primary surgery and 575 had good quality tumour samples available for tissue microarray analysis using indirect immunohistochemistry. Comparison was made with data from a well-characterised younger (<70 years) series (N = 1711) treated between 1986 and 1998 (before adjuvant trastuzumab became standard) in our institution. Forty five (7.6%) and 140 (8.2%) patients from the older and younger series, respectively, had HER2-positive tumours.

RESULTS

HER2 overexpression was seen in 45 (7.6%) older women and 140 (8.2%) in younger patients (P = 0.56). HER2 overexpressing tumours in older women when compared with that in their younger counterparts were associated with low Ki67 and high bcl2 expression (P < 0.05). Only 26% of the younger patients and none of the older patients received adjuvant chemotherapy, and no patients at the time received trastuzumab. However, there was no significant difference in the outcome of the two age groups (5-year breast cancer-specific survival rate: <70 years = 65% versus >70 years = 70%, P = 0.51).

CONCLUSION

HER2 overexpressing tumours in older women showed relatively a less aggressive phenotype and did not show any inferior long-term clinical outcome despite not having received chemotherapy when compared with the younger patients. The precise role of different adjuvant systemic therapies in this population needs to be delineated.

Biology of primary breast cancer in older women treated by surgery: with correlation with long-term clinical outcome and comparison with their younger counterparts

Background:

As age advances breast cancer appears to change its biological characteristics, however, very limited data are available to define the precise differences between older and younger patients.

Methods:

Over 36 years (1973–2009), 1758 older (⩾70 years) women with early operable primary breast cancer were managed in a dedicated clinic. In all, 813 underwent primary surgery and 575 good quality tumour samples were available for biological analysis. The pattern of biomarkers was analysed using indirect immunohistochemistry on tissue microarrays. Comparison was made with a previously characterised series of younger (<70 years) patients.

Results:

There was high expression of oestrogen receptor (ER), PgR, Bcl2, Muc1, BRCA1 and 2, E-cadherin, luminal cytokeratins, HER3, HER4, MDM2 and 4 and low expression of human epidermal growth factor receptor (HER)-2, Ki67, p53, EGFR and CK17. Oestrogen receptor and axillary stage appeared as independent prognostic factors. Unsupervised partitional clustering showed six biological clusters in older patients, five of which were common in the younger patients, whereas the low ER luminal cluster was distinct in the older series. The luminal phenotype showed better breast cancer-specific survival, whereas basal and HER2-overexpressing tumours were associated with poor outcome.

Conclusion:

Early operable primary breast cancer in older women appears as a distinct biological entity, with existence of a novel cluster. Overall older women showed less aggressive tumour biology and ER appeared as an independent prognostic factor alongside the time-dependent axillary stage. These biological characteristics may explain the differences in clinical outcome and should be considered in making therapeutic decisions.