Body mass index, waist-to-hip ratio and late outcomes: a report from the Shanghai Breast Cancer Survival Study

Germline polygenic risk scores are associated with immune gene expression signature and immune cell infiltration in breast cancer

The tumor immune microenvironment (TIME) plays key roles in tumor progression and response to immunotherapy. Previous studies have identified individual germline variants associated with differences in TIME. Here, we hypothesize that common variants associated with breast cancer risk or cancer-related traits, represented by polygenic risk scores (PRSs), may jointly influence immune features in TIME. We derived 154 immune traits from bulk gene expression profiles of 764 breast tumors and 598 adjacent normal tissue samples from 825 individuals with breast cancer in the Nurses' Health Study (NHS) and NHSII. Immunohistochemical staining of four immune cell markers were available for a subset of 205 individuals. Germline PRSs were calculated for 16 different traits including breast cancer, autoimmune diseases, type 2 diabetes, ages at menarche and menopause, body mass index (BMI), BMI-adjusted waist-to-hip ratio, alcohol intake, and tobacco smoking. Overall, we identified 44 associations between germline PRSs and immune traits at false discovery rate q < 0.25, including 3 associations with q < 0.05. We observed consistent inverse associations of inflammatory bowel disease (IBD) and Crohn disease (CD) PRSs with interferon signaling and STAT1 scores in breast tumor and adjacent normal tissue; these associations were replicated in a Norwegian cohort. Inverse associations were also consistently observed for IBD PRS and B cell abundance in normal tissue. We also observed positive associations between CD PRS and endothelial cell abundance in tumor. Our findings suggest that the genetic mechanisms that influence immune-related diseases are also associated with TIME in breast cancer.

The relationship between women's body mass index and breast cancer outcomes was U-shaped

Background

Several studies have analyzed the relationship between body mass index (BMI) and the prognosis of breast cancer (BC). However, whether their relationship is linear or curvilinear remains unclear. This cohort study examined the specific relationship between BMI and BC outcomes.

Methods

This retrospective cohort study included 1049 BC patients from March 7, 2013 through December 31, 2019 in a hospital. Kaplan-Meier curves, multivariate Cox proportional models, and restricted cubic spline (RCS) was used to analysis the relationship between BMI and overall survival (OS) and breast cancer-specific survival (BCSS) was analyzed.

Results

During a median of 4.87 (IQR:3.26-6.84) years of follow-up period, 71 patients (6.77%) died, of which 50 (70.42%) were attributed to BC. RCS analysis revealed a U- shaped relationship between BMI levels and OS and BCSS after adjusting for other variables. The turning points of the U-shaped curves were 23 kg/m2. On the left side of the turning point, the risk of OS (HR, 0.83; 95% CI, 0.70, 0.98) and BCSS (HR, 0.80; 95% CI, 0.65, 0.98) were adversely correlated with BMI. In contrast, to the right of the turning point, the risk of OS (HR, 1.22; 95% CI, 1.10, 1.37) and BCSS (HR, 1.28; 95% CI, 1.13, 1.46) was positively related to BMI. Kaplan-Meier curves and multivariate Cox regression analyses shown consistent results with RCS analyses.

Conclusion

BMI was an independent prognostic factor for BC, and had a U-shaped relationship with OS and BCSS. Interventions should be designed to improve patient outcomes based on BMI.

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

Previous evidence on postdiagnosis body fatness and mortality after breast cancer was graded as limited-suggestive. To evaluate the evidence on body mass index (BMI), waist circumference, waist-hip-ratio and weight change in relation to breast cancer prognosis, an updated systematic review was conducted. PubMed and Embase were searched for relevant studies published up to 31 October, 2021. Random-effects meta-analyses were conducted to estimate summary relative risks (RRs). The evidence was judged by an independent Expert Panel using pre-defined grading criteria. One randomized controlled trial and 225 observational studies were reviewed (220 publications). There was strong evidence (likelihood of causality: probable) that higher postdiagnosis BMI was associated with increased all-cause mortality (64 studies, 32 507 deaths), breast cancer-specific mortality (39 studies, 14 106 deaths) and second primary breast cancer (11 studies, 5248 events). The respective summary RRs and 95% confidence intervals per 5 kg/m2 BMI were 1.07 (1.05-1.10), 1.10 (1.06-1.14) and 1.14 (1.04-1.26), with high between-study heterogeneity (I2  = 56%, 60%, 66%), but generally consistent positive associations. Positive associations were also observed for waist circumference, waist-hip-ratio and all-cause and breast cancer-specific mortality. There was limited-suggestive evidence that postdiagnosis BMI was associated with higher risk of recurrence, nonbreast cancer deaths and cardiovascular deaths. The evidence for postdiagnosis (unexplained) weight or BMI change and all outcomes was graded as limited-no conclusion. The RCT showed potential beneficial effect of intentional weight loss on disease-free-survival, but more intervention trials and well-designed observational studies in diverse populations are needed to elucidate the impact of body composition and their changes on breast cancer outcomes.

Adiposity and cancer survival: a systematic review and meta-analysis

PURPOSE

The increasing availability of clinical imaging tests (especially CT and MRI) that directly quantify adipose tissue has led to a rapid increase in studies examining the relationship of visceral, subcutaneous, and overall adiposity to cancer survival. To summarize this emerging body of literature, we conducted a systematic review and meta-analysis of imaging-measured as well as anthropometric proxies for adipose tissue distribution and cancer survival across a wide range of cancer types.

METHODS

Using keywords related to adiposity, cancer, and survival, we conducted a systematic search of the literature in PubMed and MEDLINE, Embase, and Web of Science Core Collection databases from database inception to 30 June 2021. We used a random-effect method to calculate pooled hazard ratios (HR) and corresponding 95% confidence intervals (CI) within each cancer type and tested for heterogeneity using Cochran's Q test and the I2 test.

RESULTS

We included 203 records for this review, of which 128 records were utilized for quantitative analysis among 10 cancer types: breast, colorectal, gastroesophageal, head and neck, hepatocellular carcinoma, lung, ovarian, pancreatic, prostate, and renal cancer. We found that imaging-measured visceral, subcutaneous, and total adiposity were not significantly associated with increased risk of overall mortality, death from primary cancer, or cancer progression among patients diagnosed with these 10 cancer types; however, we found significant or high heterogeneity for many cancer types. For example, heterogeneity was similarly high when the pooled HRs (95% CI) for overall mortality associated with visceral adiposity were essentially null as in 1.03 (0.55, 1.92; I2 = 58%) for breast, 0.99 (0.81, 1.21; I2 = 71%) for colorectal, versus when they demonstrated a potential increased risk 1.17 (0.85, 1.60; I2 = 78%) for hepatocellular carcinoma and 1.62 (0.90, 2.95; I2 = 84%) for renal cancer.

CONCLUSION

Greater adiposity at diagnosis (directly measured by imaging) is not associated with worse survival among cancer survivors. However, heterogeneity and other potential limitations were noted across studies, suggesting differences in study design and adiposity measurement approaches, making interpretation of meta-analyses challenging. Future work to standardize imaging measurements and data analyses will strengthen research on the role of adiposity in cancer survival.

Body mass index increases the recurrence risk of breast cancer: a dose-response meta-analysis from 21 prospective cohort studies

OBJECTIVE

The purpose of this study was to investigate the effect of body mass index (BMI) on the recurrence risk of breast cancer.

STUDY DESIGN

Dose-response meta-analysis.

METHODS

Cohort studies that included BMI and the recurrence of breast cancer were selected through various databases including PubMed, Web of Science, the China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals (VIP), and Wanfang Data Knowledge Service Platform (WanFang) until November 30, 2021. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of literature. A two-stage random-effects meta-analysis was performed to assess the dose-response relationship between BMI and breast cancer recurrence risk. Heterogeneity between studies is assessed using I².

RESULTS

The relative risk (RR) of BMI <25 kg/m² vs BMI ≥25 kg/m², BMI <30 kg/m² vs BMI ≥30 kg/m² were 1.09 (95% CI: 1.00-1.19) and 1.15 (95% CI: 1.04-1.27), suggesting that BMI had a significant effect on the recurrence risk of breast cancer, and there might be a dose-response relationship between them. A total of 21 studies were included in dose-response meta-analysis, which showed that there was a positive linear correlation between BMI and the risk of recurrence (RR = 1.02, 95% CI: 1.01-1.03). For every 1 kg/m² increment of BMI, the risk of recurrence increased by approximately 2%. In subgroup analyses, positive linear dose-response relationships between BMI and recurrence risk were observed among Asian and study period >10 years groups. For every 1 kg/m² increment of BMI, the risk of recurrence increased by 3.41% and 1.87%, respectively.

CONCLUSIONS

The recurrence risk of breast cancer increases with BMI, which is most obvious among Asian women.

Associations of adiposity and weight change with recurrence and survival in breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Adiposity and weight change among patients with breast cancer are associated with mortality, but there is limited evidence on the associations with distant recurrence or other causes of death or on central adiposity. Moreover, the relationship with breast cancer subtypes and by menopause status is unclear.

METHODS

We conducted a systematic review and meta-analysis of prospective studies of breast cancer patients investigating the associations of general and central adiposity (body mass index [BMI] and waist circumference [WC], respectively), before and after diagnosis, and weight change, with all-cause mortality, breast cancer-specific mortality (BCSM), and recurrence.

RESULTS

173 studies (519,544 patients, 60,249 deaths overall, and 25,751 breast cancer deaths) were included. For BMI  < 1 year post diagnosis, compared with normal weight women, the summary relative risk (RR) for obese women was 1.21 (1.15-1.27) for all-cause mortality, 1.22 (1.13-1.32) for BCSM, 1.12 (1.06-1.18) for recurrence, and 1.19 (1.11-1.28) for distant recurrence. Obesity was associated with all-cause mortality and BCSM in patients with ER+ or HER2+ tumors, whereas no clear association was observed in patients with triple-negative tumors. Similar associations were observed by menopausal status. Stronger associations were observed in East Asians than Europeans. Central adiposity was associated with all-cause mortality, while large weight gain was associated with all-cause mortality, BCSM, and recurrence.

CONCLUSION

Higher adiposity is associated with all-cause mortality, BCSM, recurrence, and distant recurrence in breast cancer patients, with similar associations by menopausal status and some evidence of heterogeneity by subtypes. Weight gain is also associated with recurrence and survival among breast cancer patients.

Associations of Body Fat Distribution and Cardiometabolic Risk of Testicular Cancer Survivors after Cisplatin-Based Chemotherapy

Background

It is unknown how body fat distribution modulates the cardiometabolic risk of testicular cancer survivors (TCSs) after cisplatin-based chemotherapy.

Methods

For 455 patients enrolled in The Platinum Study at Memorial Sloan Kettering Cancer Center, visceral (VAT) and subcutaneous (SAT) adipose tissue was quantified on pre-chemotherapy CT. VAT/SAT ratio was calculated as a quantitative measure of central adiposity. Endpoints were incidence of new post-chemotherapy cardiometabolic disease (new antihypertensive, lipid-lowering, or diabetes medication), and post-chemotherapy Framingham risk scores. Cox models and linear regression with interaction terms were applied. Post-chemotherapy body fat distribution was analyzed in 108 patients. All statistical tests were 2-sided.

Results

Baseline median age was 31 years (IQR = 26, 39), BMI 26 kg/m2 (IQR: 24, 29), and VAT/SAT ratio 0.49 (IQR: 0.31, 0.75). Median follow-up was 26 months (IQR: 16, 59). Higher pre-chemotherapy VAT/SAT ratios inferred a higher likelihood of new cardiometabolic disease among patients with BMI ≥30 kg/m2 (age-adjusted HR = 3.14, 95% CI = 1.02–9.71, p = 0.047), but not other BMI groups. Pre-chemotherapy VAT/SAT ratio was associated with post-chemotherapy Framingham risk scores in univariate regression analysis (exp(β)-estimate: 2.10, 95% CI: 1.84, 2.39, p &lt; 0.001); in a multivariate model, this association was stronger in younger versus older individuals. BMI increased in most patients after chemotherapy and correlated with increases in VAT/SAT (Spearman r = 0.39; p &lt; 0.001).

Conclusions

In TCSs, central adiposity is associated with increased cardiometabolic risk after cisplatin-based chemotherapy, particularly in obese or young men. Weight gain after chemotherapy occurs preferentially in the visceral compartment, providing insight into the pathogenesis of cardiovascular disease in this population.

Clinical verification of body mass index and tumor immune response in patients with breast cancer receiving preoperative chemotherapy

Purpose

The body mass index (BMI) is commonly used as a simple indicator of obesity; patients with early-stage breast cancer who are obese (OB) per BMI measurements have been shown to have high postoperative recurrence and low survival rates. On the other hand, it has been shown that lymphocytes present in the vicinity of malignant growths that are involved in the tumors’ immune responses influence the efficacy chemotherapy. Therefore, we hypothesized that OB patients with breast cancer have a lower density of tumor-infiltrating lymphocytes (TILs), which may influence the therapeutic effect of preoperative chemotherapy (POC). In this study, we measured pretreatment BMI and TILs in patients with breast cancer who underwent POC, examined the correlations between these two factors, and retrospectively analyzed their therapeutic outcomes and prognoses.

Methods

The participants in this study were 421 patients with breast cancer who underwent surgical treatment after POC between February 2007 and January 2019. The patient’s height and weight were measured before POC to calculate the BMI (weight [kg] divided by the square of the height [m²]). According to the World Health Organization categorization, patients who weighed under 18.5 kg/m² were classified as underweight (UW), those ≥18.5 kg/m² and > 25 kg/m² were considered normal weight (NW), those ≥25 kg/m² and < 30 kg/m² were overweight (OW), and those ≥30 kg/m² were OB. The TILs were those lymphocytes that infiltrated the tumor stroma according to the definition of the International TILs Working Group 2014.

Results

The median BMI was 21.9 kg/m² (range, 14.3–38.5 kg/m²); most patients (244; 64.5%) were NW. Among all 378 patients with breast cancer, the TIL density was significantly lower in OB than in NW and OW patients (vs. NW: p = 0.001; vs. OW: p = 0.003). Furthermore, when examining patients with each breast cancer type individually, the OS of those with TNBC who had low BMIs was significantly poorer than that of their high-BMI counterparts (log rank p = 0.031).

Conclusions

Our data did not support the hypothesis that obesity affects the tumor immune microenvironment; however, we showed that being UW does affect the tumor immune microenvironment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08857-7.

Metabolic comorbidities and the association with risks of recurrent metastatic disease in breast cancer survivors

BACKGROUND

Obesity and other metabolic comorbidities affect over 10% of patients with breast cancer and are closely related with adverse outcomes. Although metabolic comorbidities among breast cancer patients in low- and middle-income countries are suggested to be lower, only a few studies are currently available. Effective management of metabolic comorbidities in cancer patients has been associated with better outcomes.

METHODS

Non-metastatic breast cancer patients (N = 1081) treated in our department (2014-2018) were monitored for the presence of high Body Mass Index (BMI), diabetes or glucose intolerance, dyslipidemia, and hypertension and the development of recurrent metastatic diseases during a median follow-up of 3.9 years.

RESULTS

Glucose intolerance, hypertension, dyslipidemia, and BMI ≥ 27.7 kg/m² considered at risk for metabolic comorbidities were found in 26.5, 42.6, 27.7, and 23.3% of breast cancer patients, respectively. Diabetes or glucose intolerance and having both glucose intolerance and dyslipidemia were associated with the risk of recurrent metastatic disease (OR = 1.442, 95%CI = 1.071-1.943, p = 0.016 and OR = 1.495, 95%CI = 1.090-2.049, p = 0.010; respectively). Having three or more metabolic comorbidities was significantly associated with the risk of recurrent metastatic disease (OR = 1.647, 95%CI = 1.139-2.382, p = 0.008) compared to patients without any comorbidity. The metabolic comorbidities were distributed unevenly among breast cancer subtypes. A significant association with recurrent metastatic disease was found in the Luminal B-like subtype. In post-menopausal patients, having more than three comorbidities was associated with a higher risk of recurrent metastatic disease compared to those without any comorbidity (OR = 2.000, 95%CI = 1.035-3.067, p = 0.001). The risks of having three or more metabolic comorbidities were significantly higher in breast cancer survivors who were obese, lived in an urban area, and received hormonal therapy of aromatase inhibitors.

CONCLUSION

Metabolic comorbidities were frequently found in breast cancer patients and were associated with higher risks to develop recurrent metastatic disease, particularly in post-menopausal women. Subsequent larger studies are needed to better understand the association of metabolic comorbidities with patients' quality of life and prognosis, and to explore the potential combination of clinical intervention and lifestyle modification in breast cancer survivors to treat as well as reduce their impact.

Predicting the risk of type 2 diabetes through anthropometric indices in Pakistani adults- A sub-analysis of second National diabetes survey of Pakistan 2016-2017 (NDSP-07)

BACKGROUND AND AIM

Excess adiposity is associated with an increased risk of diabetes. Amongst the various measures of adiposity, the most appropriate one to predict the risk of diabetes remains debatable. Therefore, the aim of this study was to compare the ability of body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) in predicting type 2 diabetes mellitus (DM) among Pakistani adults.

SUBJECTS AND METHODS

This was the sub-analysis of a large population based Second National Diabetes Survey of Pakistan (NDSP) 2016-2017. With this survey, 10834 individuals were recruited and 4788 individuals fulfilled the inclusion criteria for this sub-analysis (subjects with missing anthropometric details were excluded). Participants were categorized into two groups; subjects with type 2 DM and subjects without DM. Data of participants was collected via pre-designed detailed questionnaire. Clinical and anthropometric measurements were measured using standardized techniques.

RESULTS

Out of 4788 individuals, 3085(64.4%) were non-DM subjects and 1703(35.6%) were type 2 DM subjects with mean age of 39.78 ± 13.79 and 50.38 ± 11.33 years, respectively. Logistic regression analysis revealed a significant association of WC with type 2 diabetes after adjustment for possible confounders. Area under the curve (AUC) of WC was found higher than AUC of BMI and WHR.

CONCLUSION

The findings from second NDSP (2016-2017) demonstrated that WC is a better marker than WHR and BMI in predicting type 2 DM for Pakistani population.

Obesity in Gynecologic Oncology

The decades-long global obesity epidemic has resulted in steady increase in the incidence of obesity-related malignancies. The associated diagnostic and therapeutic implications present a clinical challenge for gynecologic oncology treatment strategies. Recent studies have provided solid evidence for an independent, linear, positive correlation between a pathologically increased body mass index and the probability of developing endometrial or postmenopausal breast cancer. The pathogenesis is complex and the subject of current research. Proposed causes include pathologically increased serum levels of sexual steroids and adiponectin, obesity-induced insulin resistance, and systemic inflammatory processes. The scientific evidence for an association between obesity and other gynecological malignancies is, however, less solid. The clinical relevance of obesity as a risk factor for epithelial ovarian cancer, cervical cancer and vulvar cancer appears to be negligible. Nevertheless, obesity appears to have a negative impact on prognosis and oncologic outcomes for all gynecological cancers. Whether or not this effect can be interpreted as correlative or causal is still a subject of ongoing debate.

Nutritional status and feeding habits of females in public and private Universities in Osun state, Southwestern, Nigeria

This study examined the dietary habits, nutritional status and socio-demographic characteristics of female undergraduates in selected public and private Universities in Osun State, Southwestern, Nigeria.

The anthropometric assessment of selected respondents consisted measurements of height, weight, body circumferences, body mass index and waist-to-hip ratio of respondents. The food frequency questionnaire technique was adopted to evaluate the feeding/dietary habits using well-constructed questionnaires.

The results showed that over 60% of students in both public and private Universities fell within 18.5–24.9 kg/m², the normal weight range of body mass index according to the World Health Organisation classification. From the waist-to-hip ratio result over 60% were not at risk of non-communicable disease. The respondents were fond of snacking (74.9%) and skipping of meals (86.0%) especially breakfast (52.4%). There was a significant difference (p < 0.05) in the allowances (pocket money) of students where 33.7% of private University students received over N16,000 as compared to 12% of public University students. There was no significant difference (p > 0.05) between the nutritional status of students in public and private Universities.

In conclusion, the nutritional status and the dietary habits/pattern of female undergraduate students are influenced by type of schools and other underlying factors.

Predictors of weight gain in a cohort of premenopausal early breast cancer patients receiving chemotherapy

AIM

In breast cancer patients, post chemotherapy weight gain is linked with increased risk of cancer recurrence. We prospectively studied a cohort of premenopausal women receiving contemporary chemotherapy following a diagnosis of breast cancer to examine factors predicting weight increase.

METHODS

Between May 2005 and January 2008, 523 patients from the Prospective Outcomes in Sporadic versus Hereditary (POSH) breast cancer study entered this sub-study comparing weight prior to chemotherapy and weight and waist/hip measurements 12-months following chemotherapy.

RESULTS

Data from 380 patients were available. Mean (standard deviation [SD]) pre-treatment body mass index (BMI) was 26.3 (5.6) kg/m2; 30% women gained > 5% body weight during the study period. Lower BMI at diagnosis predicted greater subsequent post treatment weight gain (4.3% relative weight gain for those in the 1st quartile of BMI compared to 0.8% for those in the 4th quartile; r = -0.22; p < 0.001). No link to chemotherapy regimens, cigarette smoking, previous parity or chemotherapy induced amenorrhoea was noted. A total of 44% of women had central obesity (post-treatment waist measurement of ≥88 cm).

CONCLUSIONS

Almost a third of premenopausal patients receiving adjuvant chemotherapy for breast cancer will gain clinically significant weight and over 40% will have central obesity 12-months following diagnosis. A greater weight gain is predicted by lower pretreatment BMI.

Clinicopathologic and Prognostic Significance of Body Mass Index (BMI) among Breast Cancer Patients in Western China: A Retrospective Multicenter Cohort Based on Western China Clinical Cooperation Group (WCCCG)

Introduction

Clinicopathologic and prognostic significance of body mass index (BMI) in breast cancer (BC) patients remained conflicting. We aimed to investigate and modify the impact of BMI on clinicopathological significance and survival in western Chinese BC patients.

Materials and Methods

8,394 female BC patients from Western China Clinical Cooperation Group (WCCCG) between 2005 and 2015 were identified. Multivariable logistic regression and Cox proportion hazard regressions were used to examine the difference of clinicopathologic and survival characteristics between BMI categories.

Results

For the premenopausal, overweight and obese (OW) patients tended to have large tumor size (>5cm) (odds ratio [OR], 1.30, P<0.01) and triple-negative BC (OR, 1.31; P=0.01) compared with normal weight (NW) patients. Premenopausal underweight (UW) patients had a significantly higher risk of HER2 positive (OR, 1.71; P=0.02) and distant metastasis (OR, 2.59; P=0.01). For postmenopausal patients, OW patients showed higher risks of large tumor size (>5cm) (OR, 1.46; P=0.01), nuclear grade III (OR, 1.24; P=0.04), and lymphovascular invasion (OR, 1.46; P=0.01) compared with NW patients. An "U" shaped relationship between BMI and DFS was found (UW versus NW, adjusted hazard ratio (HR), 2.80, P<0.001; OW versus NW, adjusted HR, 1.40, P=0.02), whereas no significant difference of disease-free survival (DFS) between OW and NW premenopausal patients (adjusted HR=1.34, P=0.18) was revealed.

Conclusion

We concluded that UW and OW were associated with aggressively clinicopathological characteristics, regardless of menopausal status. An "U" shaped association of BMI and DFS was revealed, and no significant difference of DFS between OW and NW in postmenopausal subgroup was revealed.

Metabolic syndrome and risk of breast cancer mortality by menopause, obesity, and subtype

PURPOSE

To investigate the association between metabolic syndrome (MetS) and risk of breast cancer mortality by menopausal status, obesity, and subtype.

METHODS

Data from 94,555 women free of cancer at baseline in the National Institute of Health-American Association of Retired Persons Diet and Health Study cohort (NIH-AARP) were used to investigate the prospective associations of baseline MetS and components with risk of breast cancer mortality using Cox proportional hazard regression models adjusted for baseline behavioral and demographic covariates.

RESULTS

During a mean follow-up duration of 14 years, 607 women in the cohort died of breast cancer. Overall, MetS was associated with a 73% increased risk of breast cancer mortality (HR 1.73; 95% CI 1.09-2.75); the association remained significant among post-menopausal women overall (HR 2.07, 95% CI 1.32, 3.25), and among those with overweight/obesity (HR 1.15, 95% CI 0.81, 1.64). MetS was associated with increased risk of breast cancer mortality for ER+/PR+ (HR 1.28, 95% CI 0.52, 3.16) and lower risk for ER-/PR- (HR 0.44, 95% CI 0.11, 1.75) subtypes; however, the associations were not statistically significant. Of the individual MetS components, high waist circumference (HR 1.32, 95% CI 1.03, 1.70), high cholesterol (HR 1.24, 95% CI 1.05, 1.46), and hypertension (HR 1.24, 95% CI 1.05, 1.46) were independently associated with increased risk of breast cancer mortality.

CONCLUSIONS

MetS was associated with increased risk of breast cancer mortality, especially among post-menopausal women. Further studies with larger sample sizes are needed to definitively determine the extent to which these associations vary by breast cancer subtype.

Breast cancer risk factors, survival and recurrence, and tumor molecular subtype: analysis of 3012 women from an indigenous Asian population

BACKGROUND

Limited evidence, mostly from studies in Western populations, suggests that the prognostic effects of lifestyle-related risk factors may be molecular subtype-dependent. Here, we examined whether pre-diagnostic lifestyle-related risk factors for breast cancer are associated with clinical outcomes by molecular subtype among patients from an understudied Asian population.

METHODS

In this population-based case series, we evaluated breast cancer risk factors in relation to 10-year all-cause mortality (ACM) and 5-year recurrence by molecular subtype among 3012 women with invasive breast cancer in Sarawak, Malaysia. A total of 579 deaths and 314 recurrence events occurred during a median follow-up period of ~ 24 months. Subtypes (luminal A-like, luminal B-like, HER2-enriched, triple-negative) were defined using immunohistochemical markers for hormone receptors and human epidermal growth factor receptor 2 (HER2) in conjunction with histologic grade. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between risk factors and ACM/recurrence were estimated in subtype-specific Cox regression models.

RESULTS

We observed heterogeneity in the relationships between parity/breastfeeding, age at first full-term pregnancy (FFP), family history, body mass index (BMI), and tumor subtype (p value < 0.05). Among luminal A-like patients only, older age at menarche [HR (95% CI) _{≥15 vs ≤ 12 years} = 2.28 (1.05, 4.95)] and being underweight [HR_{BMI < 18.5kg/m}²_{vs. 18.5-24.9kg/m}² = 3.46 (1.21, 9.89)] or overweight [HR_25-29.9kg/m²_{vs. 18.5-24.9kg/m}²₌ 3.14 (1.04, 9.50)] were associated with adverse prognosis, while parity/breastfeeding [HR_{breastfeeding vs nulliparity} = 0.48 (0.27, 0.85)] and older age at FFP [HR _{> 30 vs < 21 years} = 0.20 (0.04, 0.90)] were associated with good prognosis. For these women, the addition of age at menarche, parity/breastfeeding, and BMI, provided significantly better fit to a prognostic model containing standard clinicopathological factors alone [LRχ² (8df) = 21.78; p value = 0.005]. Overall, the results were similar in relation to recurrence.

CONCLUSIONS

Our finding that breastfeeding and BMI were associated with prognosis only among women with luminal A-like breast cancer is consistent with those from previously published data in Western populations. Further prospective studies will be needed to clarify the role of lifestyle modification, especially changes in BMI, in improving clinical outcomes for women with luminal A-like breast cancer.