A Comparison of Clinical Features, Pathology and Outcomes in Various Subtypes of Breast Cancer in Indian Women

Association of reproductive risk factors and breast cancer molecular subtypes: a systematic review and meta-analysis

BACKGROUND

Associations between reproductive factors and breast cancer (BC) risk vary by molecular subtype (i.e., luminal A, luminal B, HER2, and triple negative/basal-like [TNBC]). In this systematic review and meta-analysis, we summarized the associations between reproductive factors and BC subtypes.

METHODS

Studies from 2000 to 2021 were included if BC subtype was examined in relation to one of 11 reproductive risk factors: age at menarche, age at menopause, age at first birth, menopausal status, parity, breastfeeding, oral contraceptive (OC) use, hormone replacement therapy (HRT), pregnancy, years since last birth and abortion. For each reproductive risk factor, BC subtype, and study design (case-control/cohort or case-case), random-effects models were used to estimate pooled relative risks and 95% confidence intervals.

RESULTS

A total of 75 studies met the inclusion criteria for systematic review. Among the case-control/cohort studies, later age at menarche and breastfeeding were consistently associated with decreased risk of BC across all subtypes, while later age at menopause, later age of first childbirth, and nulliparity/low parity were associated with increased risk of luminal A, luminal B, and HER2 subtypes. In the case-only analysis, compared to luminal A, postmenopausal status increased the risk of HER2 and TNBC. Associations were less consistent across subtypes for OC and HRT use.

CONCLUSION

Identifying common risk factors across BC subtypes can enhance the tailoring of prevention strategies, and risk stratification models can benefit from subtype specificity. Adding breastfeeding status to current BC risk prediction models can enhance predictive ability, given the consistency of the associations across subtypes.

Prevalence of Molecular Subtypes in Operated Cases of Breast Cancer and Its Clinicopathological Correlation: A Single Institute Study from a Tertiary Cancer Centre in North India

Breast cancer has emerged as a major health problem among women in India. There are few Indian studies which have looked at prevalence of molecular subtypes of breast cancer in Indian population. The primary objective of our study was to find out the prevalence of various molecular subtypes in operated cases of breast cancer patients presenting to us. Three hundred sixty patients who were operated in our department were analysed. Clinicopathological features of all cases were recorded. Classification into various molecular subtypes was done using St. Gallen 2013 criteria. Luminal B HER2 negative was the predominant molecular subtype in our study population constituting 30.3% of patients. The percentage of aggressive subtypes, viz. triple negative breast cancer and HER2 enriched, were 21.7% and 11.4% respectively. Only 19.4% of patients in our study population had tumour size ≤ 2 cm with nodes being positive in 56.9% of our patients at presentation. Data from our study and other studies published from India show that the two most aggressive subtypes of, viz. triple negative breast cancer and HER2 enriched, may be more prevalent in our population as compared to western population.

Alternative splicing of ceramide synthase 2 alters levels of specific ceramides and modulates cancer cell proliferation and migration in Luminal B breast cancer subtype

Global dysregulation of RNA splicing and imbalanced sphingolipid metabolism has emerged as promoters of cancer cell transformation. Here, we present specific signature of alternative splicing (AS) events of sphingolipid genes for each breast cancer subtype from the TCGA-BRCA dataset. We show that ceramide synthase 2 (CERS2) undergoes a unique cassette exon event specifically in Luminal B subtype tumors. We validated this exon 8 skipping event in Luminal B cancer cells compared to normal epithelial cells, and in patient-derived tumor tissues compared to matched normal tissues. Differential AS-based survival analysis shows that this AS event of CERS2 is a poor prognostic factor for Luminal B patients. As Exon 8 corresponds to catalytic Lag1p domain, overexpression of AS transcript of CERS2 in Luminal B cancer cells leads to a reduction in the level of very-long-chain ceramides compared to overexpression of protein-coding (PC) transcript of CERS2. We further demonstrate that this AS event-mediated decrease of very-long-chain ceramides leads to enhanced cancer cell proliferation and migration. Therefore, our results show subtype-specific AS of sphingolipid genes as a regulatory mechanism that deregulates sphingolipids like ceramides in breast tumors, and can be explored further as a suitable therapeutic target.

Prevalence of Molecular Subtypes of Breast Cancer in India: a Systematic Review and Meta-analysis

In the last two decades, India has witnessed a substantial increase in the incidence of breast cancer and associated mortality. Studies on the prevalence of molecular subtypes of breast cancer in India have reported inconsistent results. Therefore, we conducted a systematic review of observational studies to document the prevalence of molecular subtypes of breast cancer. A complete literature search for observational studies was conducted in MEDLINE and EMBASE databases using key MeSH terms ((molecular classification) OR (molecular subtypes)) AND (breast cancer)) OR (breast carcinoma)) AND (prevalence)) AND (India). Two reviewers independently reviewed the retrieved studies. The screened studies satisfying the eligibility were included. The quality of included studies was assessed using the selected STROBE criteria. The overall pooled prevalence of luminal A, luminal B, HER2-enriched, and triple-negative breast cancer (TNBC) subtypes of breast cancer were 0.33 (95% CI 0.23-0.44), 0.17 (95% CI 0.12-0.23), 0.15 (95% CI 0.12-0.19), and 0.30 (95% CI 0.27-0.33), respectively. Subgroup analyses were performed by mean age of patients, time period, region, and sample size of the study. Among molecular subtypes of breast cancer, luminal A was the most prevalent subtype followed by TNBC, luminal B, and HER2-enriched subtypes. The overall prevalence of TNBC in India is high compared to other regions of the world. Additional research is warranted to identify the determinants of high TNBC in India. Differentiating TNBC from other molecular subtypes is important to guide therapeutic management of breast cancer.

Meta-Analysis of Prevalence of Triple-Negative Breast Cancer and Its Clinical Features at Incidence in Indian Patients With Breast Cancer

PURPOSE

Breast cancer is the most common cancer in women in India, with higher incidence rates of aggressive subtypes, such as triple-negative breast cancer (TNBC).

METHODS

A systematic review was performed to compute pooled prevalence rates of TNBC among patients with breast cancer, and clinical features at presentation were systematically compared with non-TNBC in an Indian cohort of 20,000 patients.

RESULTS

Combined prevalence of TNBC among patients with breast cancer was found to be on the higher side (27%; 95% CI, 24% to 31%). We found that the estrogen receptor (ER) expression cutoff used to determine ER positivity had an influence on the pooled prevalence and ranged from 30% (ER/progesterone receptor [PR] cut ff at 1%) to 24% (ER/PR cutoff at 10%). Odds for TNBC to present in the younger age-group were significantly higher (pooled odds ratio [OR], 1.35; 95% CI, 1.08 to 1.69), with a significantly younger mean age of incidence (weighted mean difference, -2.75; 95% CI, -3.59 to -1.92). TNBC showed a significantly higher odds of presenting with high grade (pooled OR, 2.57; 95% CI, 2.12 to 3.12) and lymph node positivity (pooled OR, 1.39; 95% CI, 1.21 to 1.60) than non-TNBC.

CONCLUSION

Systematic review and meta-analysis of 34 studies revealed a high degree of heterogeneity in prevalence of TNBC within Indian patients with breast cancer, yet pooled prevalence of TNBC is high in India. High proportions of patients with TNBC present with aggressive features, such as high grade and lymph node positivity, compared with patients without TNBC. We emphasize the need for standardized methods for accurate diagnosis in countries like India.

Prevalence of Molecular Subtypes of Breast Cancer: A Single Institutional Experience of 2062 Patients

Objective

The aim of the study was to analyze the prevalence of molecular subtypes of all breast cancer patients treated at tertiary cancer centre in West India in 12 years.

Materials and Methods

A retrospective observational study carried out in Tertiary Cancer Care Centre in Western India. Electronic medical records of all breast cancer patients were retrieved from the hospital database between March 2007 to March 2019. Patient's characteristic, histological features and molecular subtypes were collected and analyzed.

Results

A total of 2062 women fulfilled the criteria for this study and were analyzed. The median age of study population was 51 years (range 22-100 years). Among these, 1357 (65.8%) were of ≤55 years and 705 (34.2%) were over 55 years. The overall incidence of Hormonal Receptor-positive patients (either estrogen-receptor (ER) or progesterone-receptor (PR) or both) was 1162 (56.4%). The Mean tumor size was 3.8cm (range 0-18cm). The most common histology was IDC (96%). Axillary nodes were positive in 62.5%. Luminal type A was positive in 762 (37%) patients while Luminal type B was present in 157 (7.6%) patients. Basal-like subtype was observed in 537 (26%) patients while HER2 rich subtype was seen in 229 (11.1%). The incidence of Luminal A subtype increased with age. The highest observed among patients (72%) aged 70 years or more. Incidence of Basal like subtype was highest in patients less than 30 years (52%).

Conclusion

Luminal-like disease is the most common molecular subtype in India. Identification of Basal like breast cancer, a highly aggressive, biologically and clinically distinct subtype different than its non-basal variant, is important for treatment planning and target therapy.

Clinicopathological features and survival of early stage breast cancer in northwest China: A population-based retrospective study of 1287 patients

Background

Breast cancer (BC) displays different clinicopathological features and outcomes based on patient age, molecular subtype, and treatment. However, such features in BC patients in northwest China are unclear. This study investigated the clinicopathological features and overall survival (OS) of early stage BC patients using a population‐based study.

Methods

Patients who were newly diagnosed with BC at the First Affiliated Hospital of Xi'an Jiaotong University between January 2001 and June 2012 were included. Clinicopathological features and OS were assessed.

Results

The median age of 1287 patients was 50 years, with an average tumor size of 2.65 cm. Additionally, 42.7% were luminal A, 25.6% luminal B, 9.3% Her2 overexpression, and 17.7% triple negative. The cut‐off age was 35 years, and young patients (< 35) tended to have larger tumors, ≥ 4 positive lymph nodes, grade 2 or 3 histology, non‐luminal types, high Ki67, and poor outcomes. Patients with luminal A tumors showed moderate features: 50.6% had tumors < 2 cm, 56.7% had negative lymph nodes. Patients with Her2 overexpression tumors showed aggressive features and the poorest survival (5‐year OS 67.6%). Patients with triple negative tumors were the youngest (average 48.4 years), but had the largest proportion of grade 3 histology and poor outcomes.

Conclusion

Our results are consistent with those in other provinces in China, but showed an earlier age at diagnosis and more aggressive pathological features compared to developed countries. Additionally, each molecular subtype showed specific features and different survival outcomes.

Breast cancer: An overview of published Indian data

The Incidence of breast cancer has been steadily increasing in the last two decades, more so in urban areas of the sub-continent. Cancer ceters across the country have large numbers of patients being treated with multiple publications in this field. Inspite of paucity of prospective data and randomised clinical trials from India, there are large number of retrospective publications on various aspects of the disease including pathology, radiology, surgery, chemotherapy, radiation, palliative care and alternatitive treatment modalities. These published data provide an insight into the trends of breast cancer in the country and this comprehensive data review of Indian data will provide a basis for designing trials relevant to our population and planning health care.

Prevalence of Triple-Negative Breast Cancer in India: Systematic Review and Meta-Analysis

Purpose

There is considerable variation in prevalence rates of triple-negative breast cancer (TNBC) reported by various studies from India. We performed a systematic review and literature-based meta-analysis of these studies.

Methods

We searched databases of Medline, Scopus, EMBASE, and Web of Science for studies that reported on the prevalence of TNBC in India that were published between January 1, 1999, and December 31, 2015. We extracted relevant information from each study by using a standardized form. We pooled study-specific estimates by using random-effects meta-analysis to provide summary estimates. We explored sources of heterogeneity by using subgroup analyses and metaregression.

Results

Data were obtained from 17 studies that involved 7,237 patients with breast cancer. Overall combined prevalence of TNBC was 31% (95% CI, 27% to 35%). There was substantial heterogeneity across the studies (I² of 91% [95% CI, 88% to 94%]; P < .001) that was not explained by available study level characteristics, including study location, definition of human epidermal growth factor receptor 2 or estrogen receptor, mean age of participants, proportion of patients with premenopausal cancer, grade 3 disease, or tumor size > 5 cm. Overall combined prevalence of hormone receptor–positive and human epidermal growth factor receptor 2–positive breast cancer was 48% (95% CI, 42% to 54%) and 27% (95% CI, 24% to 31%), respectively. There was no evidence of publication bias.

Conclusion

Prevalence of TNBC in India is considerably higher compared with that seen in Western populations. As many as as one in three women with breast cancer could have triple-negative disease. This finding has significant clinical relevance as it may contribute to poor outcomes in patients with breast cancer in India. Additional research is needed to understand the determinants of TNBC in India.