The Association between Obesity and Premenopausal Breast Cancer According to Intrinsic Subtypes – a Systematic Review

Abstract

Introduction Obesity is a well-established risk factor for postmenopausal hormone-receptor positive breast cancer. The relationship between premenopausal breast cancer intrinsic subtypes and obesity is not completely elucidated; therefore, this systematic review was conducted to give an overview about the existing evidence. Methods This review followed the PRISMA Statement for Systematic Reviews and Meta-analyses. Full electronic search was conducted in PubMed and Orbis for articles published in English between January 2008 and June 2018. The literature search was performed in June 2018 using search strings that combined the Medical Subject Headings (MeSH terms) keywords and/or text words in any field were used: “body mass index” (BMI) OR obesity OR overweight AND premenopausal breast cancer. Results 391 articles were found to be eligible, of which ultimately 21 were included comprising a total of 55 580 breast cancer patients. 45% were case-control studies, 35% were single cohort studies, 15% were cohort studies, two were cross-sectional studies, one was a multicenter-study and one was a pooled analysis. The evidence shows a tendency for an increased risk for the more aggressive triple negative breast cancer subtype in obese premenopausal women and a decreased risk for less aggressive tumor subtypes such as the luminal A subtype. The evidence is limited by small sample sizes for triple negative and HER2-positive subtypes in severely obese patients. Conclusion Higher BMI might influence aggressive tumor characteristics among premenopausal women and has divergent impacts on the risk of different breast cancer subtypes. Further research is needed to confirm these results and to evaluate potential pathophysiologic mechanisms for the relationship between obesity and aggressive premenopausal breast cancer subtypes.

Type 2 Diabetes Mellitus and Clinicopathological Tumor Characteristics in Women Diagnosed with Breast Cancer: A Systematic Review and Meta-Analysis

“…Since specific morphologic and prognostic characteristics of young-onset breast cancer were advocated in previous findings [ 38 ], such as enhanced likelihood to be a large and poorly differentiated tumor, or less often containing hormone receptors at diagnosis, we further stratified the studies by age at breast cancer diagnosis, and found an increased risk of tumors without PR expression in young patients. High BMI (≥25 kg/m 2 ) was confirmed as another risk factor for developing breast cancer [ 85 ], and more specifically, obesity increases the risk for hormone receptor-positive breast cancer in postmenopausal women, but tends to increase the risk for TNBC in premenopausal women [ 86 ]. Evidence of the relation between BMI and Her2 status is limited [ 86 ].…”

“…High BMI (≥25 kg/m 2 ) was confirmed as another risk factor for developing breast cancer [ 85 ], and more specifically, obesity increases the risk for hormone receptor-positive breast cancer in postmenopausal women, but tends to increase the risk for TNBC in premenopausal women [ 86 ]. Evidence of the relation between BMI and Her2 status is limited [ 86 ]. Here, stratified analyses found a positive association between T2DM and lack of Her2 expression in studies [ 42 , 43 ] with BMI adjustment; these two studies had small sample sizes and recruited younger participants.…”

Update Breast Cancer 2021 Part 1 – Prevention and Early Stages

“…Außerdem scheint es weitere metabolische Faktoren zu geben, die unabhängig vom BMI einen Einfluss auf das Brustkrebsrisiko haben 43 . Auch hinsichtlich der Prognose konnte gezeigt werden, dass Übergewicht einen negativen Einfluss auf den Krankheitsverlauf und den molekularen Subtyp hat 46 , 47 . Dies lässt vermuten, dass eine Verbindung von Metabolismus und Brustkrebsrisiko mit komplexeren Mechanismen existiert.…”

“…Moreover, there seem to be other metabolic factors affecting the risk of breast cancer independently of BMI [43]. With regard to prognosis, it has also been established that obesity has a negative effect on the course of the disease and the molecular subtype [46,47] This suggests a link between metabolism and breast cancer risk with more complex mechanisms. One study looking into this is the cohort study "NutriNet-Santé" [48].…”

Age Under 30 Years As a Predictor of Poor Survival in a Cohort of Mexican Women With Breast Cancer

“… 4 , 5 Increased body mass index (BMI) in premenopausal women shows a higher proportion of hormone receptor negative, with a predominance of triple negative breast cancer (TNBC) molecular subtype. 6 , 7 …”