World Cancer Research Fund International: Continuous Update Project-systematic literature review and meta-analysis of observational cohort studies on physical activity, sedentary behavior, adiposity, and weight change and breast cancer risk. Cancer Causes Control. 2019;30:1183-1200. [PMID: 31471762 DOI: 10.1007/s10552-019-01223-w]

The unique risk factor profile of triple-negative breast cancer: a comprehensive meta-analysis

BACKGROUND

Triple-negative breast cancer (TNBC) has a poor prognosis compared with other breast cancer subtypes. This systematic review and meta-analysis examines whether known risk factors for breast cancer are also associated with TNBC in adult women.

METHODS

EMBASE, Medline, SCOPUS, and gray literature were queried with no limit on the date or language of publication. The exposures of interest included parity, breastfeeding, duration of breastfeeding, age at menarche, age at first live birth, oral contraceptive (OC) use, duration of OC use, use of menopausal hormone therapy (MHT), family history, body mass index (BMI), alcohol use, smoking, and breast density. The main outcome of interest was TNBC. Study quality was determined using the Newcastle-Ottawa scale for case control studies and cohort studies. We estimated weighted odds ratios from random effects models to study the exposure-outcome associations. Protocol was registered under the number: PROSPERO 2021 CRD42021254594.

RESULTS

Thirty-three studies were included. Family history, longer duration of OC use, and higher breast density were significantly associated with increased risk for TNBC, whereas later age at menarche, later age at first birth, and breastfeeding were protective against TNBC. Parity, MHT, alcohol, smoking, and BMI were not significantly associated with TNBC overall, but higher parity was associated with higher risk among Black women.

CONCLUSION

Our findings highlight that TNBC has a distinct risk factor profile compared with overall breast cancer. This can be the foundational work in identification of actionable TNBC risk factors to improve prevention and early detection of these poor prognosis breast tumors.

Non-genetic factors and breast cancer: an umbrella review of meta-analyses

BACKGROUND

Previous research has found associations between various non-genetic factors and breast cancer (BrCa) risk. This study summarises and appraises the credibility of the available evidence on the association between non-genetic factors and BrCa risk.

METHODS

We conducted an umbrella review of meta-analyses. Medline, Scopus, and the Cochrane databases were systematically searched for meta-analyses examining non-genetic factors and BrCa incidence or mortality. The strength of the evidence was graded in four categories (i.e., weak, suggestive, highly suggestive, convincing).

RESULTS

A total of 781 meta-analyses from 280 publications were evaluated and graded. We included exposures related to anthropometric measurements, biomarkers, breast characteristics and diseases, diet and supplements, environment, exogenous hormones, lifestyle and social factors, medical history, medication, reproductive history, and pregnancy. The largest number of examined associations was found for the category of diet and supplements and for exposures such as aspirin use and active smoking. The statistically significant (P-value < 0.05) meta-analyses were 382 (49%), of which 204 (53.4%) reported factors associated with increased BrCa risk. Most of the statistically significant evidence (n = 224, 58.6%) was graded as weak. Convincing harmful associations with heightened BrCa risk were found for increased body mass index (BMI), BMI and weight gain in postmenopausal women, oral contraceptive use in premenopausal women, increased androstenedione, estradiol, estrone, and testosterone concentrations, high Breast Imaging Reporting and Data System (BIRADS) classification, and increased breast density. Convincing protective factors associated with lower BrCa risk included high fiber intake and high sex hormone binding globulin (SHBG) levels while highly suggestive protective factors included high 25 hydroxy vitamin D [25(OH)D] levels, adherence to healthy lifestyle, and moderate-vigorous physical activity.

CONCLUSIONS

Our findings suggest some highly modifiable factors that protect from BrCa. Interestingly, while diet was the most studied exposure category, the related associations failed to reach higher levels of evidence, indicating the methodological limitations in the field. To improve the validity of these associations, future research should utilise more robust study designs and better exposure assessment techniques. Overall, our study provides knowledge that supports the development of evidence-based BrCa prevention recommendations and guidance, both at an individual level and for public health initiatives.

TRIAL REGISTRATION

PROSPERO CRD42022370675.

Mammographic features differ with body composition in women with breast cancer

OBJECTIVES

There are several breast cancer (BC) risk factors-many related to body composition, hormonal status, and fertility patterns. However, it is not known if risk factors in healthy women are associated with specific mammographic features at the time of BC diagnosis. Our aim was to assess the potential association between pre-diagnostic body composition and mammographic features in the diagnostic BC image.

MATERIALS AND METHODS

The prospective Malmö Diet and Cancer Study includes women with invasive BC from 1991 to 2014 (n = 1116). BC risk factors at baseline were registered (anthropometric measures, menopausal status, and parity) along with mammography data from BC diagnosis (breast density, mammographic tumor appearance, and mode of detection). We investigated associations between anthropometric measures and mammographic features via logistic regression analyses, yielding odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

There was an association between high body mass index (BMI) (≥ 30) at baseline and spiculated tumor appearance (OR 1.370 (95% CI: 0.941-2.010)), primarily in women with clinically detected cancers (OR 2.240 (95% CI: 1.280-3.940)), and in postmenopausal women (OR 1.580 (95% CI: 1.030-2.440)). Furthermore, an inverse association between high BMI (≥ 30) and high breast density (OR 0.270 (95% CI: 0.166-0.438)) was found.

CONCLUSION

This study demonstrated an association between obesity and a spiculated mass on mammography-especially in women with clinically detected cancers and in postmenopausal women. These findings offer insights on the relationship between risk factors in healthy women and related mammographic features in subsequent BC.

CLINICAL RELEVANCE STATEMENT

With increasing numbers of both BC incidence and women with obesity, it is important to highlight mammographic findings in women with an unhealthy weight.

KEY POINTS

Women with obesity and BC may present with certain mammographic features. Spiculated masses were more common in women with obesity, especially postmenopausal women, and those with clinically detected BCs. Insights on the relationship between obesity and related mammographic features will aid mammographic interpretation.

Recreational physical activity and breast cancer risk by menopausal status and tumor hormone receptor status: results from the Nurses' Health Studies

PURPOSE

Physical activity is associated with lower breast cancer risk, especially in postmenopausal women. Associations in premenopausal women are less well established.

METHODS

We evaluated recreational physical activity and breast cancer risk in the Nurses' Health Study (NHS) and NHSII (187,278 women; n = 12,785 breast cancers; follow-up: NHS = 1986-2016, NHSII = 1989-2017) by menopausal status and estrogen (ER) and progesterone (PR) receptor status. Physical activity was evaluated as updated cumulative average of metabolic equivalent of task (MET)-h/week. Cox proportional hazards models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Recreational physical activity was inversely associated with breast cancer risk in pre- and postmenopausal women. Higher activity levels were associated with lower risk of ER+/PR + breast cancer in both pre- and postmenopausal women (e.g., total recreational activity, ≥ 27 vs < 3 MET-h/week, premenopausal HR = 0.83, 95%CI = (0.70-0.99), postmenopausal HR = 0.86 (0.78-0.95); pheterogeneity = 0.97). Results were attenuated with adjustment for current body mass index (BMI) among postmenopausal, but not premenopausal, women (e.g., ≥ 27 vs < 3 MET-h/week, premenopausal HR = 0.83 (0.69-0.98); postmenopausal HR = 0.95 (0.85-1.05); pheterogeneity = 0.99). In analyses of moderate-vigorous activity and breast cancer risk, no heterogeneity by menopausal status was observed (phet ≥ 0.53; e.g., ≥ 27 vs < 3 MET-h/week, ER+/PR+, premenopausal HR = 0.88 (0.69-1.11); postmenopausal HR = 0.71 (0.58-0.88). No associations were observed for ER-/PR- disease.

CONCLUSIONS

Recreational physical activity was associated with lower breast cancer risk in both pre- and postmenopausal women, supporting recreational physical activity as an accessible, modifiable exposure associated with reduced breast cancer risk regardless of menopausal status.

Obesity and Early-Onset Breast Cancer and Specific Molecular Subtype Diagnosis in Black and White Women: NIMHD Social Epigenomics Program

Importance

Epidemiologic data suggest an association of obesity with breast cancer (BC); however, obesity's contribution to early onset and risk of diagnosis with specific molecular subtypes by race is uncertain.

Objective

To examine the race-specific association of body mass index with early onset and diagnosis of specific molecular subtypes.

Design, Setting, and Participants

This retrospective cohort study included patients with BC diagnosed between October 1, 2017, and March 31, 2022, at 3 University of South Alabama Mitchell Cancer Institute clinics. Participants were also prospectively enrolled for serum leptin measurement.

Main Outcomes and Measures

The primary outcome was age at BC onset and specific subtype diagnosis. The secondary outcome was race-specific differences. Odds ratios (ORs) for associations of body mass index with age at onset and subtype were estimated using the Fisher exact test. Race was self-reported.

Results

Of the 1085 study patients, 332 (30.6%) were Black with a median age of 58 (IQR, 50-66) years, and 753 (69.4%) were White with a median age of 63 (IQR, 53-71) years. A total of 499 patients (46.0%) had obesity, with Black women with obesity receiving more frequent BC diagnosis than their White counterparts (OR, 2.40; 95% CI, 1.87-3.15; P < .001). In addition, Black women had a significantly higher incidence of early-onset disease (OR, 1.95; 95% CI, 1.33-2.86; P = .001) than White women, and obesity increased this risk significantly in Black women (OR, 2.92; 95% CI, 1.35-6.22; P = .006). Black women with obesity also had a significantly higher risk of luminal A BC (OR, 2.53; 95% CI, 1.81-3.56; P < .001) and triple-negative BC (TNBC) (OR, 2.48; 95% CI, 1.43-4.22; P = .002) diagnosis than White counterparts. Black women, with or without BC, had significantly higher serum leptin levels (median [IQR], 55.3 [40.3-66.2] ng/mL and 29.1 [21.1-46.5] ng/mL, respectively, P < .001) than White women (median [IQR], 33.4 [18.9-47.7] ng/mL and 16.5 [10.0-22.9] ng/mL, respectively), which was associated with higher odds of luminal A disease (OR, 5.25; 95% CI, 1.69-14.32, P = .003). Higher odds of early-onset disease (OR, 3.50; 95% CI, 0.43-23.15; P = .33 for trend), and TNBC diagnosis (OR, 6.00; 95% CI, 0.83-37.27; P = .14 for trend) were also seen, although these outcomes were not statistically significant.

Conclusions and Relevance

In this cohort study of patients with BC, obesity and high serum leptin levels were associated with an enhanced risk of early-onset BC and diagnosis of luminal A and TNBC subtypes in Black women. These findings should help in developing strategies to narrow the existing disparity gaps.

Synchronous or metachronous breast and colorectal cancers in younger-than-average-age patients: a case series

BACKGROUND

The incidence of breast and colorectal cancer (CRC) in younger-than-average-age patients is rising and poorly understood. This is the largest study on patients with both cancers who are less than 60 years old and aims to characterize demographic, clinicopathologic, and genetic features and describe therapeutic dilemmas and management strategies.

MATERIALS AND METHODS

This is a retrospective medical records review of patients at the University of California San Francisco with both primary breast and CRC before age 60.

RESULTS

Fifty-one patients were identified; 41 had detailed medical records. Median age of diagnosis with breast cancer was 43 (range 27-59) and CRC was 50 (28-59). Most were Caucasian (38, 74.5%) and never smokers (23, 56.1%); about half were current alcohol consumers (20, 48.8%) and about one-third had sedentary jobs (14, 34.1%). Average BMI was 25.8 (range: 14-49), and 30% were overweight or obese. Breast was the first cancer diagnosed in 36 patients (70.6%) and 44 (86.3%) had a metachronous CRC diagnosis. Breast cancer was early stage (0-2) in 32 (78.0%) patients whereas CRC was split between early stage (1-2) in 14 (34.1%) and later stage (3-4) in 19 (46.2%). Ten patients (24.3%) had a known germline mutation, although 23 (56.1%) had a family history of cancer in a first-degree relative.

CONCLUSION

Younger patients with both breast and CRC are a unique cohort, often without known risk factors. Alcohol consumption and sedentary jobs were the most common risk factors, and about one-quarter had a known genetic predisposition. Comanagement of both cancers requires individualized, multidisciplinary care.

Sedentary Behaviors, Light-Intensity Physical Activity, and Healthy Aging

Importance

Sleep duration and moderate-to-vigorous physical activity (MVPA) are associated with healthy aging, but the associations of sedentary behaviors and light-intensity physical activity (LPA) with healthy aging are still unclear.

Objective

To examine the independent association of sedentary behaviors and LPA with healthy aging, and to estimate the theoretical association of replacing sedentary behavior with LPA, MVPA, or sleep with healthy aging.

Design, Setting, and Participants

In this cohort study using data from the Nurses' Health Study, participants aged 50 years or older and free of major chronic diseases in 1992 were prospectively followed up for 20 years. Data were analyzed from January to May 2022.

Exposures

Three measures for sedentary behaviors (hours watching television, sitting at work, and other sitting at home) and 2 measures for LPA (hours of standing or walking around at home [LPA-Home] and at work [LPA-Work]).

Main Outcomes and Measures

Healthy aging was defined as survival to at least age 70 years with maintenance of 4 health domains (ie, no major chronic diseases and no impairment in subjective memory, physical function, or mental health). The isotemporal substitution model was used to evaluate the potential impact on healthy aging of replacing 1 hour of 1 behavior with equivalent duration of another.

Results

Among 45 176 participants (mean [SD] age, 59.2 [6.0] years), 3873 (8.6%) women achieved healthy aging. After adjustment for covariates including MVPA, each increment of 2 hours per day in sitting watching television was associated with a 12% (95% CI, 7%-17%) reduction in the odds of healthy aging. In contrast, each increase of 2 hours per day in LPA-Work was associated with a 6% (95% CI, 3%-9%) increase in the odds of healthy aging. Replacing 1 hour of sitting watching television with LPA-Home (OR, 1.08; 95% CI, 1.05-1.12), LPA-Work (OR, 1.10; 95% CI, 1.07-1.14), or MVPA (OR, 1.28; 95% CI, 1.23-1.34) was associated with increased odds of healthy aging. Among participants who slept 7 hours per day or less, replacing television time with sleep was also associated with increased odds of healthy aging.

Conclusions and Relevance

In this cohort study, longer television watching time decreased odds of healthy aging, whereas LPA and MVPA increased odds of healthy aging and replacing sitting watching television with LPA or MVPA, or with sleep in those who slept 7 hours per day or less, was associated with increased odds of healthy aging, providing evidence for rearranging 24-hour behavior to promote overall health.

The Association between Cardiorespiratory Fitness and the Risk of Breast Cancer in Women

INTRODUCTION

Studies have shown an inverse association between the risk of breast cancer in women and physical activity. However, information on the association between cardiorespiratory fitness (CRF) assessed objectively by a standardized test and the risk of developing breast cancer is limited.

PURPOSE

To examine the CRF-breast cancer risk association in healthy females.

METHODS

This retrospective study was derived from the Exercise Testing and Health Outcomes Study cohort ( n = 750,302). Female participants ( n = 44,463; mean age ± SD; 55.1 ± 8.9 yr) who completed an exercise treadmill test evaluation (Bruce protocol) at the Veterans Affairs Medical Centers nationwide from 1999 to 2020 were studied. The cohort was stratified into four age-specific CRF categories (Least-fit, Low-fit, Moderate-fit, and Fit), based on the peak METs achieved during the exercise treadmill test.

RESULTS

During 438,613 person-years of observation, 994 women developed breast cancer. After controlling for covariates, the risk of breast cancer was inversely related to exercise capacity. For each 1-MET increase in CRF, the risk of cancer was 7% lower (HR, 0.93; 95% CI, 0.90-0.95; P < 0.001). When risk was assessed across CRF categories with the Least-fit group as the referent, the risk was 18% lower for Low-fit women (HR, 0.82; 95% CI, 0.70-0.96; P = 0.013), 31% for Moderate-fit (HR, 0.69; 95% CI, 0.58-0.82; P < 0.001), and 40% for Fit (HR, 0.60; 95% CI, 0.47-0.75; P < 0.001).

CONCLUSIONS

We observed an inverse and graded association between CRF and breast cancer risk in women. Thus, encouraging women to improve CRF may help attenuate the risk of developing breast cancer.

Racial disparities in breast cancer risk factors and risk management

Racial disparities in breast cancer outcomes are well described across the spectrum of screening, diagnosis, treatment, and survivorship. Breast cancer mortality is markedly elevated for Non-Hispanic Black women compared with other racial and ethnic groups, with multifactorial causes. Here, we aim to reduce this burden by identifying disparities in breast cancer risk factors, risk assessment, and risk management before breast cancer is diagnosed. We describe a reproductive profile and modifiable risk factors specific to the development of triple-negative breast cancer. We also propose that screening strategies should be both risk- and race-based, given the prevalence of early-onset triple-negative breast cancer in young Black women. We emphasize the importance of early risk assessment and identification of patients at hereditary and familial risk and discuss indications for a high-risk referral. We discuss the subtleties following genetic testing and highlight "uncertain" genetic testing results and risk estimation challenges in women who test negative. We trace aspects of the obesity epidemic in the Black community to infant feeding patterns and emphasize healthy eating and activity. Finally, we discuss building an environment of trust to foster adherence to recommendations, follow-up care, and participation in clinical trials. Addressing relevant social determinants of health; educating patients and clinicians on factors impacting disparities in outcomes; and encouraging participation in targeted, culturally sensitive research are essential to best serve all communities.

Interaction of sedentary behaviour and educational level in breast cancer risk

OBJECTIVE

This cross-sectional study aims to analyse the relationship between sedentary behaviour and breast cancer (BC) risk from a social perspective.

METHODS

Women aged 45-70 who participated in the Valencia Region Breast Cancer Screening Programme (2018-2019) were included, with a total of 121,359 women analysed, including 506 with cancer and 120,853 without cancer. The response variable was BC (screen-detected) and the main explanatory variable was sedentary behaviour (≤2 / >2-≤3 / >3-≤5 / >5 hours/day, h/d). Nested logistic regression models (M) were estimated: M1: sedentary behaviour adjusted for age and family history of BC; M2: M1 + hormonal/reproductive variables (menopausal status, number of pregnancies, hormone replacement therapy; in addition, months of breastfeeding was added for a subsample of women with one or more live births); M3: M2 + lifestyle variables (body mass index, smoking habits); M4: M3 + socioeconomic variables (educational level, occupation); Final model: M4 + gender variables (childcare responsibilities, family size). Interaction between sedentary behaviour and educational level was analysed in the Final model. Moreover, for the whole sample, postmenopausal women and HR+ BC, the Final model was stratified by educational level.

RESULTS

Sedentary behaviour was associated with an increased risk of BC with a nearly statistically significant effect in the Final model (>2-≤3 h/d: OR = 1.22 (0.93-1.61); >3-≤5 h/d: OR = 1.14 (0.86-1.52); >5: OR = 1.19 (0.89-1.60)). For women with a low educational level, sitting more than 2 h/d was associated with an increased risk of BC in the whole sample (>2-≤3 h/d OR = 1.93 (1.19-3.21); in postmenopausal women (>2-≤3 h/d, OR = 2.12 (1.18-2.96), >5h/d OR = 1.75 (1.01-3.11)) and in HR+ BC (>2-≤3h/d, OR = 2.15 (1.22-3.99)). Similar results were observed for women with one or more live births. Conclusions Sitting >2 h/d is associated with BC risk in women with low educational level, especially in postmenopausal women and those with live births.

Outcomes of physical exercises on initiation, progression, and treatment of breast cancer

The emergence of drug resistance is a substantial obstacle to the effective management of breast cancer, which is the primary cause of cancer-related deaths in women worldwide. To facilitate the development of targeted therapies that can effectively overcome drug resistance, it is crucial to possess a comprehensive comprehension of the molecular mechanisms that underpin resistance to breast cancer treatment. So far, considerable progress has been made in the field of exercise-oncology research and overcome drug resistance, specifically about breast cancer. Evidence has suggested that participation in physical activity is correlated with a decrease in reappearance and fatality rates of breast cancer patients. It has been reported that participation in physical activity can yield favorable outcomes in the prevention, treatment, and post-treatment of breast cancer. An increasing body of empirical evidence suggests that participation in physical activity can alter diverse biological mechanisms, potentially augmenting breast cancer treatments' efficacy. Comparing increased physical activity versus reduced physical activity in breast cancer patients who received chemotherapy, radiotherapy, and surgery supported the significance of exercise in comprehensive care strategies to enhance overall health and treatment efficacy. Furthermore, previous studies have reported that physical activity can enhance the efficacy of breast cancer treatments. This review provides the current literature regarding the influence of physical activity on the occurrence and progression of breast cancer.

Causes and Risk Factors of Breast Cancer, What Do We Know for Sure? An Evidence Synthesis of Systematic Reviews and Meta-Analyses

Breast cancer affected more than 2.3 million women in 2022 and is the most diagnosed cancer among women worldwide. The incidence rates are greater in developed regions and are significantly higher among women with higher education and socioeconomic status. Therefore, it is reasonable to assume that the way women live their lives may impact their risk of being diagnosed with breast cancer. This systematic review aimed to identify what is known about the causes and risk factors of breast cancer, excluding genetic causes. A comprehensive systematic search identified 2387 systematic reviews, 122 were included and six overall themes identified. In our "top list" with the 36 most important findings, a study of breast density had the highest effect size for increasing the risk of breast cancer, and a high sex-hormone-binding globulin level was the most protective factor. Many of the included studies investigating the same topics had conflicting results. The conclusion from this evidence synthesis reveals a lack of consensus of factors associated with the causes and risk of breast cancer. These findings suggest that recommendations about lifestyle and breast cancer should be made with caution.

Trends in breast cancer mortality attributable to metabolic risks in Chinese women from 1990 to 2019: an age-period-cohort analysis

Objective

Metabolic risks (MRs) are the primary determinants of breast cancer (BC) mortality among women. This study aimed to examine the changing trends in BC mortality associated with MRs and explore how they related to age, time period, and birth cohorts in Chinese women aged 25 and above.

Methods

Data were sourced from the Global Burden of Disease Study 2019 (GBD2019). The BC mortality trajectories and patterns attributable to MRs were assessed using Joinpoint regression. The age-period-cohort (APC) model was employed to evaluate cohort and time period effects.

Results

The age-standardized mortality rate (ASMR) of BC mortality linked to MRs displayed an escalating trend from 1990 to 2019, demonstrating an average annual percentage change (AAPC) of 1.79% (95% CI: 1.69~1.87). AAPCs attributable to high fasting plasma glucose (HFPG) and high body mass index (HBMI) were 0.41% (95% CI: 0.32~0.53) and 2.75% (95% CI: 2.68~2.82), respectively. APC analysis revealed that BC mortality due to HBMI in women aged 50 and above showed a rise with age and mortality associated with HFPG consistently demonstrated a positive correlation with age. The impact of HBMI on BC mortality significantly outweighed that of HFPG. The risk of BC mortality linked to HBMI has steadily increased since 2005, while HFPG demonstrated a trend of initial increase followed by a decrease in the period effect. Regarding the cohort effect, the relative risk of mortality was greater in the birth cohort of women after the 1960s of MRs on BC mortality, whereas those born after 1980 displayed a slight decline in the relative risk (RR) associated with BC mortality due to HBMI.

Conclusion

This study suggests that middle-aged and elderly women should be considered as a priority population, and control of HBMI and HFPG should be used as a primary tool to control metabolic risk factors and effectively reduce BC mortality.

Associations between transport modes and site-specific cancers: a systematic review and meta-analysis

BACKGROUND

Physical inactivity is a global public health problem. A practical solution would be to build physical activity into the daily routine by using active modes of transport. Choice of transport mode can influence cancer risk through their effects on levels of physical activity, sedentary time, and environmental pollution. This review synthesizes existing evidence on the associations of specific transport modes with risks of site-specific cancers.

METHODS

Relevant literature was searched in PubMed, Embase, and Scopus from 1914 to 17th February 2023. For cancer sites with effect measures available for a specific transport mode from two or more studies, random effects meta-analyses were performed to pool relative risks (RR) comparing the highest vs. lowest activity group as well as per 10 Metabolic Equivalent of Task (MET) hour increment in transport-related physical activity per week (∼150 min of walking or 90 min of cycling).

RESULTS

27 eligible studies (11 cohort, 15 case-control, and 1 case-cohort) were identified, which reported the associations of transport modes with 10 site-specific cancers. In the meta-analysis, 10 MET hour increment in transport-related physical activity per week was associated with a reduction in risk for endometrial cancer (RR: 0.91, 95% CI: 0.83-0.997), colorectal cancer (RR: 0.95, 95% CI: 0.91-0.99) and breast cancer (RR: 0.99, 95% CI: 0.89-0.996). The highest level of walking only or walking and cycling combined modes, compared to the lowest level, were significantly associated with a 12% and 30% reduced risk of breast and endometrial cancers respectively. Cycling, compared to motorized modes, was associated with a lower risk of overall cancer incidence and mortality.

CONCLUSION

Active transport appears to reduce cancer risk, but evidence for cancer sites other than colorectum, breast, and endometrium is currently limited.

New Horizons: Epidemiology of Obesity, Diabetes Mellitus, and Cancer Prognosis

The global prevalence of obesity and diabetes mellitus has increased in parallel with increasing cancer incidence, due to environmental and lifestyle factors and population aging. Metabolic diseases are associated with increased cancer risk, so a growing number of patients with cancer have coexistent obesity and/or diabetes mellitus. In this narrative review, we highlight recent evidence on the clinical impact of obesity and diabetes mellitus on the prognosis of prostate, breast, and colorectal cancer, and provide an overview of the underlying mechanisms. There is evidence that obesity is associated with increased risk of recurrence, and all-cause and cancer-specific mortality among adults with prostate, breast, and colorectal cancer. Diabetes mellitus is associated with increased all-cause and cancer-specific mortality for these 3 cancers, beyond any impact of obesity. Evidence also suggests increased risk of colorectal cancer recurrence in patients with diabetes mellitus. The underlying mechanisms are multifactorial and likely include hormonal imbalances and chronic inflammation that promote cancer cell growth. Obesity and diabetes mellitus are associated with increased risk of complications and side effects of cancer treatment. Associated comorbidities such as impaired kidney function, cardiovascular disease, and neuropathies may preclude the use of guideline cancer treatment and are competing causes of death. Cancer patients with metabolic diseases require a designated clinical program and a multidisciplinary approach involving oncologists, endocrinologists, surgeons, nutritionists, and physiotherapists, to ensure coordinated and optimized patient care.

International Pooled Analysis of Leisure-Time Physical Activity and Premenopausal Breast Cancer in Women From 19 Cohorts

PURPOSE

There is strong evidence that leisure-time physical activity is protective against postmenopausal breast cancer risk but the association with premenopausal breast cancer is less clear. The purpose of this study was to examine the association of physical activity with the risk of developing premenopausal breast cancer.

METHODS

We pooled individual-level data on self-reported leisure-time physical activity across 19 cohort studies comprising 547,601 premenopausal women, with 10,231 incident cases of breast cancer. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% CIs for associations of leisure-time physical activity with breast cancer incidence. HRs for high versus low levels of activity were based on a comparison of risk at the 90th versus 10th percentiles of activity. We assessed the linearity of the relationship and examined subtype-specific associations and effect modification across strata of breast cancer risk factors, including adiposity.

RESULTS

Over a median 11.5 years of follow-up (IQR, 8.0-16.1 years), high versus low levels of leisure-time physical activity were associated with a 6% (HR, 0.94 [95% CI, 0.89 to 0.99]) and a 10% (HR, 0.90 [95% CI, 0.85 to 0.95]) reduction in breast cancer risk, before and after adjustment for BMI, respectively. Tests of nonlinearity suggested an approximately linear relationship (Pnonlinearity = .94). The inverse association was particularly strong for human epidermal growth factor receptor 2-enriched breast cancer (HR, 0.57 [95% CI, 0.39 to 0.84]; Phet = .07). Associations did not vary significantly across strata of breast cancer risk factors, including subgroups of adiposity.

CONCLUSION

This large, pooled analysis of cohort studies adds to evidence that engagement in higher levels of leisure-time physical activity may lead to reduced premenopausal breast cancer risk.

How does weight gain since the age of 18 years affect breast cancer risk in later life? A meta-analysis

Early life factors are important risk factors for breast cancer. The association between weight gain after age 18 and breast cancer risk is inconsistent across previous epidemiologic studies. To evaluate this association, we conducted a meta-analysis according to PRISMA guidelines and the established inclusion criteria. We performed a comprehensive literature search using Medline (Ovid), Embase, Scopus, Cochrane Library, and ClinicalTrials.gov to identify relevant studies published before June 3, 2022. Two reviewers independently reviewed the articles for final inclusion. Seventeen out of 4,725 unique studies met the selection criteria. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS), and all were of moderate to high quality with NOS scores ranging from 5 to 8. We included 17 studies (11 case-control, 6 cohort) in final analysis. In case-control studies, weight gain after age 18 was associated with an increased risk of breast cancer (odds ratio [OR] = 1.25; 95% CI = 1.07-1.48), when comparing the highest versus the lowest categories of weight gain. Menopausal status was a source of heterogeneity, with weight gain after age 18 associated with an increased risk of breast cancer in postmenopausal women (OR = 1.53; 95% CI = 1.40-1.68), but not in premenopausal women (OR = 1.01; 95% CI = 0.92-1.12). Additionally, a 5 kg increase in weight was positively associated with postmenopausal breast cancer risk (OR = 1.12; 95%CI = 1.05-1.21) in case-control studies. Findings from cohort studies were identical, with a positive association between weight gain after age 18 and breast cancer incidence in postmenopausal women (relative risk [RR] = 1.30; 95% CI = 1.09-1.36), but not in premenopausal women (RR = 1.06; 95% CI = 0.92-1.22). Weight gain after age 18 is a risk factor for postmenopausal breast cancer, highlighting the importance of weight control from early adulthood to reduce the incidence of postmenopausal breast cancer.

Assessing the survival time of women with breast cancer in Northwestern Ethiopia: using the Bayesian approach

BACKGROUND

Despite the significant weight of difficulty, Ethiopia's survival rate and mortality predictors have not yet been identified. Finding out what influences outpatient breast cancer patients' survival time was the major goal of this study.

METHODS

A retrospective study was conducted on outpatients with breast cancer. In order to accomplish the goal, 382 outpatients with breast cancer were included in the study using information obtained from the medical records of patients registered at the University of Gondar referral hospital in Gondar, Ethiopia, between May 15, 2016, and May 15, 2020. In order to compare survival functions, Kaplan-Meier plots and the log-rank test were used. The Cox-PH model and Bayesian parametric survival models were then used to examine the survival time of breast cancer outpatients. The use of integrated layered Laplace approximation techniques has been made.

RESULTS

The study included 382 outpatients with breast cancer in total, and 148 (38.7%) patients died. 42 months was the estimated median patient survival time. The Bayesian Weibull accelerated failure time model was determined to be suitable using model selection criteria. Stage, grade 2, 3, and 4, co-morbid, histological type, FIGO stage, chemotherapy, metastatic number 1, 2, and >=3, and tumour size all have a sizable impact on the survival time of outpatients with breast cancer, according to the results of this model. The breast cancer outpatient survival time was correctly predicted by the Bayesian Weibull accelerated failure time model.

CONCLUSIONS

Compared to high- and middle-income countries, the overall survival rate was lower. Notable variables influencing the length of survival following a breast cancer diagnosis were weight loss, invasive medullar histology, comorbid disease, a large tumour size, an increase in metastases, an increase in the International Federation of Gynaecologists and Obstetricians stage, an increase in grade, lymphatic vascular space invasion, positive regional nodes, and late stages of cancer. The authors advise that it is preferable to increase the number of early screening programmes and treatment centres for breast cancer and to work with the public media to raise knowledge of the disease's prevention, screening, and treatment choices.

Lifestyle changes in middle age and risk of cancer: evidence from the European Prospective Investigation into Cancer and Nutrition

In this study, we aimed to provide novel evidence on the impact of changing lifestyle habits on cancer risk. In the EPIC cohort, 295,865 middle-aged participants returned a lifestyle questionnaire at baseline and during follow-up. At both timepoints, we calculated a healthy lifestyle index (HLI) score based on cigarette smoking, alcohol consumption, body mass index and physical activity. HLI ranged from 0 (most unfavourable) to 16 (most favourable). We estimated the association between HLI change and risk of lifestyle-related cancers-including cancer of the breast, lung, colorectum, stomach, liver, cervix, oesophagus, bladder, and others-using Cox regression models. We reported hazard ratios (HR) with 95% confidence intervals (CI). Median time between the two questionnaires was 5.7 years, median age at follow-up questionnaire was 59 years. After the follow-up questionnaire, we observed 14,933 lifestyle-related cancers over a median follow-up of 7.8 years. Each unit increase in the HLI score was associated with 4% lower risk of lifestyle-related cancers (HR 0.96; 95%CI 0.95-0.97). Among participants in the top HLI third at baseline (HLI > 11), those in the bottom third at follow-up (HLI ≤ 9) had 21% higher risk of lifestyle-related cancers (HR 1.21; 95%CI 1.07-1.37) than those remaining in the top third. Among participants in the bottom HLI third at baseline, those in the top third at follow-up had 25% lower risk of lifestyle-related cancers (HR 0.75; 95%CI 0.65-0.86) than those remaining in the bottom third. These results indicate that lifestyle changes in middle age may have a significant impact on cancer risk.

Association of physical weight statuses defined by body mass index (BMI) with molecular subtypes of premenopausal breast cancer: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

The association between overweight/obesity and postmenopausal breast cancer has been proven. However, uncertainty exists regarding the association between physical weight statuses and premenopausal breast cancer subtypes. This study aimed to explore the association of body weight statuses with molecular subtypes of premenopausal breast cancer.

METHOD

A systematic search of Medline, PubMed, Embase, and Web of Science was performed. The Newcastle-Ottawa Scale (NOS) and the Joanna Briggs Institute (JBI) Critical Appraisal tools were used to evaluate the quality of the literature. STATA and R software were used to analyze the extracted data.

RESULT

The meta-analysis included 35 observational studies with a total of 41,049 premenopausal breast cancer patients. The study showed that the proportion of underweight patients was 4.8% (95% CI = 3.9-5.8%, P = 0.01), overweight was 29% (95%CI = 27.1-30.9%, P < 0.01), obesity was 17.8% (95% CI = 14.9-21.2%, P < 0.0001), and normal weight was 51.6% (95% CI = 46.7-56.5%, P < 0.0001). The pooled results showed that in comparison to the normal weight group, being physically underweight is related to a 1.44-fold risk (OR = 1.44, 95%CI = 1.28-1.63, P < 0.0001) of HER2 + breast cancer. Overweight is related to a 1.16-fold risk (OR = 1.16, 95%CI = 1.06-1.26, P = 0.002) of TNBC and a 16% lower risk (OR = 0.84, 95%CI = 0.75-0.93, P = 0.001) of ER + breast cancer. When compared to underweight/normal weight populations, both overweight (OR = 0.74, 95%CI = 0.56-0.97, P = 0.032) and obesity (OR = 0.70, 95%CI = 0.50-0.98, P = 0.037) can reduce the risk of ER + PR + breast cancer.

CONCLUSION

In the premenopausal breast cancer population, the distribution of patients' numbers with different weight statuses was significantly distinct among the various breast cancer subtypes. Additionally, the associations between physical weight statuses and the risk of premenopausal breast cancer subtypes are divergent.

Compliance with the WCRF/AICR Recommendations in Qualitative Adaptation and the Occurrence of Breast Cancer: A Case-Control Study

PURPOSE

The aim of the study was twofold: (1) the qualitative adaptation of the 2018 WCRF/AICR (QAd-WCRF/AICR) score, and (2) the assessment of the association between the level of compliance with the WCRF/AICR recommendations and the occurrence of breast cancer in peri- and postmenopausal women.

METHODS

This case-control study involved 420 women, aged 40-79 years, from northeastern Poland, including 190 newly diagnosed breast cancer cases. Data related to the WCRF/AICR recommendations were collected in face-to-face interviews with 409 women, including 179 women with breast cancer. The frequency of food consumption data were collected using the FFQ-6® and KomPAN® questionnaires. Body weight, height, and waist circumference were measured. The QAd-WCRF/AICR score (range: 0-8 points) was calculated on the basis of eight components, including two components from to the WCRF/AICR recommendations: (1) body mass index (BMI), and (2) waist circumference, with six components expressed qualitatively: (3) overall physical activity, as well as the frequency of the consumption of (4) vegetables/fruits/whole grains/nuts/seeds/legumes, (5) highly processed foods, including fast foods/sweets/instant soups, (6) red/processed meat, (7) sweetened/energy drinks, and (8) alcohol. Logistic regression analysis was performed to assess the occurrence of breast cancer.

RESULTS

The moderate (4-5 points) and maximal (6-8 points) compliance with the qualitative adaptation of the WRCF/AICR recommendations reduced the odds of breast cancer by 54% and 72%, respectively, compared to the results noted for minimal compliance (≤3 points). Lower odds of breast cancer were associated with moderate or high physical activity, consumption of a minimum of four serving per day of vegetables/fruits/whole grains/nuts/seeds/legumes, and limiting the consumption of highly processed food/fast foods and red/processed meat to a maximum of 1-3 times/month. Higher odds of breast cancer were associated with a higher waist circumference and alcohol abstinence.

CONCLUSIONS

These findings may prove useful in establishing cancer prevention recommendations based on simple suggestions regarding the frequency of food consumption.

Trajectories of body mass index across the lifecourse and associations with post-menopausal breast cancer by estrogen receptor status

BACKGROUND

Associations between a high body mass index (BMI) at single timepoints during child- and adulthood and risks of post-menopausal breast cancer are well-established, but associations with BMI across the lifecourse remains largely unknown. Therefore, we examined whether lifecourse BMI trajectories were associated with risks of post-menopausal breast cancer overall and by estrogen receptor (ER) status.

METHODS

We included 6698 Danish women born 1930-1946. Information on BMI at ages 6-15 years came from the Copenhagen School Health Records Register, and information on BMI at ages 20, 30, 40, 50 and/or 50-64 years came from the Diet, Cancer and Health cohort. Breast cancer cases (n = 577) were identified in the Danish Breast Cancer Cooperative Group database. Six BMI trajectories were identified using latent class trajectory modelling. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression models.

RESULTS

Compared to women with a trajectory characterized by an average BMI gain across life, women with the two trajectories with steep increases in BMI during childhood and adolescence that thereafter largely stabilized, had lower risks of post-menopausal breast cancer and ER-positive tumors. The adjusted HRs for ER-positive tumors were 0.67 (95% CI: 0.47-0.95) and 0.68 (95% CI: 0.46-1.01), respectively. In contrast, women with a trajectory with a low gain in BMI during childhood and adolescence followed by a subsequent steep increase during adulthood, had higher risks of post-menopausal breast cancer and ER-positive tumors when compared to women with an average BMI gain. The adjusted HR for ER-positive tumors was 1.28 (95% CI: 0.98-1.67).

CONCLUSIONS

Our findings suggest that the timing of excess gain in BMI across the lifecourse impacts subsequent post-menopausal breast cancer risks. Thus, the BMI development across life is likely useful in the identification of women at increased risks of post-menopausal breast cancer.

[Nutrition in breast cancer genesis]

Introduction

Breast cancer is the most prevalent tumor in women, ranking first in incidence and mortality in many countries. Although the causes of breast cancer are complex and multifactorial, nutritional factors and those related to nutritional status play an important role in the development of the disease. In this way, factors that increase breast cancer risk have been identified, such as weight gain, the amount of adipose tissue, waist circumference, alcohol consumption or the consumption of red meat and processed meat, while other factors have been identified that reduce the risk, such as eating fruits and vegetables. Nutritional factors or factors that depend on the state of nutrition are modifiable and preventable, so they must be considered when designing effective prevention programs.

Agreement between Accelerometer-Assessed and Self-Reported Physical Activity and Sedentary Behavior in Female Breast Cancer Survivors

An accurate quantitative assessment of physical activity and sedentary lifestyles enables a better understanding of their relationship with the health records of cancer survivors. The objective of this study was to compare the subjective and objective methods of physical activity measurement in female breast cancer survivors. Materials and methods: In total, 135 female breast cancer survivors at the Holycross Cancer Center, Kielce, Poland, were included in this study. A shortened version of the International Physical Activity Questionnaire (IPAQ) was used to subjectively assess the participants' physical activity (PA), and an ActiGraph GT3X-BT accelerometer was used for an objective assessment. In total, 75% of the studied women did not report any vigorous PA, irrespective of the measurement method. The average values of moderate PA and moderate-to-vigorous PA (MVPA) measured with IPAQ compared with the accelerometer were sevenfold and tenfold higher, respectively. Conversely, the sedentary behavior values measured with the accelerometer were almost three times higher than those measured with IPAQ. The PA and sedentary behavior measurements were significantly different. Irrespective of PA intensity, the accelerometer-based measurements produced significantly lower results than IPAQ, while higher results were observed for sedentary behavior. The measurement differences between these two methods increased as the average differences grew. Regardless of the measurement method, a negative association was observed between moderate PA with general adiposity and adipose tissue distribution, whereas sedentary behavior demonstrated an opposite trend. This indicates the detrimental role of obesity in limiting PA.

The relationship between central obesity and risk of breast cancer: a dose-response meta-analysis of 7,989,315 women

Purpose

Central obesity may contribute to breast cancer (BC); however, there is no dose-response relationship. This meta-analysis examined the effects of central obesity on BC and their potential dose-response relationship.

Methods

In the present study, PubMed, Medline, Embase, and Web of Science were searched on 1 August 2022 for published articles. We included the prospective cohort and case-control studies that reported the relationship between central obesity and BC. Summary effect size estimates were expressed as risk ratios (RRs) or odds ratios (ORs) with 95% confidence intervals (95% CI) and were evaluated using random-effect models. The inconsistency index (I2) was used to quantify the heterogeneity magnitude derived from the random-effects Mantel-Haenszel model.

Results

This meta-analysis included 57 studies (26 case-control and 31 prospective cohort) as of August 2022. Case-control studies indicated that waist circumference (WC) (adjusted OR = 1.18; 95% CI: 1.00-1.38; P = 0.051) and waist-to-hip ratio (WHR) (adjusted OR = 1.28; 95% CI: 1.07-1.53; P = 0.008) were significantly positively related to BC. Subgroup analysis showed that central obesity measured by WC increased the premenopausal (adjusted OR = 1.15; 95% CI: 0.99-1.34; P = 0.063) and postmenopausal (adjusted OR = 1.18; 95% CI: 1.03-1.36; P = 0.018) BC risk and the same relationship appeared in WHR between premenopausal (adjusted OR = 1.38; 95% CI: 1.19-1.59; P < 0.001) and postmenopausal (adjusted OR = 1.41; 95% CI: 1.22-1.64; P < 0.001). The same relationship was observed in hormone receptor-positive (HR+) (adjusted ORWC = 1.26; 95% CI: 1.02-1.57; P = 0.035, adjusted ORWHR = 1.41; 95% CI: 1.00-1.98; P = 0.051) and hormone receptor-negative (HR-) (adjusted ORWC = 1.44; 95% CI: 1.13-1.83; P = 0.003, adjusted ORWHR = 1.42; 95% CI: 0.95-2.13; P = 0.087) BCs. Prospective cohort studies indicated that high WC (adjusted RR = 1.12; 95% CI: 1.08-1.16; P < 0.001) and WHR (adjusted RR = 1.05; 95% CI: 1.018-1.09; P = 0.017) may increase BC risk. Subgroup analysis demonstrated a significant correlation during premenopausal (adjusted RR = 1.08; 95% CI: 1.02-1.14; P = 0.007) and postmenopausal (adjusted RR = 1.14; 95% CI: 1.10-1.19; P < 0.001) between BC and central obesity measured by WC, and WHR was significantly positively related to BC both premenopausal (adjusted RRpre = 1.04; 95% CI: 0.98-1.11; P = 0.169) and postmenopausal (adjusted RRpost = 1.04; 95% CI: 1.02-1.07; P = 0.002). Regarding molecular subtype, central obesity was significantly associated with HR+ (adjusted ORWC = 1.13; 95% CI: 1.07-1.19; P < 0.001, adjusted ORWHR = 1.03; 95% CI: 0.98-1.07; P = 0.244) and HR- BCs (adjusted ORWC =1.11; 95% CI: 0.99-1.24; P = 0.086, adjusted ORWHR =1.01; 95% CI: 0.91-1.13; P = 0.808). Our dose-response analysis revealed a J-shaped trend in the relationship between central obesity and BC (measured by WC and WHR) in case-control studies and an inverted J-shaped trend between BMI (during premenopausal) and BC in the prospective cohort.

Conclusion

Central obesity is a risk factor for premenopausal and postmenopausal BC, and WC and WHR may predict it. Regarding the BC subtype, central obesity is proven to be a risk of ER+ and ER- BCs. The dose-response analysis revealed that when BMI (during premenopausal) exceeded 23.40 kg/m2, the risk of BC began to decrease, and WC higher than 83.80 cm or WHR exceeded 0.78 could efficiently increase the BC risk.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022365788.

Trajectories of body mass index in adulthood and risk of subtypes of postmenopausal breast cancer

BACKGROUND

Body fatness is a dynamic exposure throughout life. To provide more insight into the association between body mass index (BMI) and postmenopausal breast cancer, we aimed to examine the age at onset, duration, intensity, and trajectories of body fatness in adulthood in relation to risk of breast cancer subtypes.

METHODS

Based on self-reported anthropometry in the prospective Norwegian Women and Cancer Study, we calculated the age at onset, duration, and intensity of overweight and obesity using linear mixed-effects models. BMI trajectories in adulthood were modeled using group-based trajectory modeling. We used Cox proportional hazards models to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the associations between BMI exposures and breast cancer subtypes in 148,866 postmenopausal women.

RESULTS

A total of 7223 incident invasive postmenopausal breast cancer cases occurred during follow-up. Increased overweight duration and age at the onset of overweight or obesity were associated with luminal A-like breast cancer. Significant heterogeneity was observed in the association between age at overweight and overweight duration and the intrinsic-like subtypes (pheterogeneity 0.03). Compared with women who remained at normal weight throughout adulthood, women with a descending BMI trajectory had a reduced risk of luminal A-like breast cancer (HR 0.54, 95% CI 0.33-0.90), whereas women with ascending BMI trajectories were at increased risk (HR 1.09; 95% CI 1.01-1.17 for "Normal-overweight"; HR 1.20; 95% CI 1.07-1.33 for "Normal-obesity"). Overweight duration and weighted cumulative years of overweight and obesity were inversely associated with luminal B-like breast cancer.

CONCLUSIONS

In this exploratory analysis, decreasing body fatness from obesity in adulthood was inversely associated with overall, hormone receptor-positive and luminal A-like breast cancer in postmenopausal women. This study highlights the potential health benefits of reducing weight in adulthood and the health risks associated with increasing weight throughout adult life. Moreover, our data provide evidence of intrinsic-like tumor heterogeneity with regard to age at onset and duration of overweight.

Obesity and Risk of Recurrence in Patients With Breast Cancer Treated With Aromatase Inhibitors

Importance

Clinical studies confirm that obesity is a risk factor for recurrence in postmenopausal women with hormone receptor-positive (HR+) breast cancer. Evidence suggests that women with obesity do not obtain similar protection from aromatase inhibitors as women with healthy weight.

Objective

To examine the associations of body mass index (BMI) with recurrence.

Design, Setting, and Participants

The cohort study was conducted using data from the Danish Breast Cancer Group and enrolled postmenopausal women diagnosed with stage I to III HR+ breast cancer from 1998 through 2016. Data analysis was conducted from November 2022 to April 2023.

Exposures

BMI was classified as (1) healthy weight (18.5-24.9), (2) overweight (25.0-29.9), (3) obesity (30.0-34.9), and (4) severe obesity (≥35.0) using the World Health Organization guidelines. Healthy weight was considered the reference group in statistical analyses.

Main Outcomes and Measures

Follow-up began 6 months after breast cancer surgery and continued until the first event of recurrence, contralateral breast cancer, new primary malignant neoplasm, death, emigration, end of clinical follow-up at 10 years, or September 25, 2018. Cox regression was used to estimate crude and adjusted hazard ratios with 95% CIs, adjusting for patient, tumor, and treatment characteristics.

Results

A total of 13 230 patients (median [IQR] age at diagnosis, 64.4 [58.6-70.2] years) with information on BMI were enrolled. There were 1587 recurrences with a median (IQR) potential estimated follow-up of 6.2 (3.6-8.5) years. Multivariable analyses revealed increased recurrence hazards associated with obesity (adjusted hazard ratio, 1.18 [95% CI, 1.01-1.37]) and severe obesity (adjusted hazard ratio, 1.32 [95% CI, 1.08-1.62]) vs patients with healthy weight. Patients with overweight had a greater risk, but the results were not statistically significant (adjusted hazard ratio, 1.10 [95% CI, 0.97-1.24]).

Conclusions and Relevance

In this study, obesity was associated with an increased risk of breast cancer recurrence among postmenopausal patients with HR+ early-stage breast cancer treated with aromatase inhibitors. Physicians should be aware of the significance of obesity on breast cancer outcomes to secure optimal treatment benefit in all patients.

Socioeconomic Status at Birth and Breast Tissue Composition in Adolescence and Adulthood

BACKGROUND

Socioeconomic status (SES) at birth is associated with breast cancer risk. Whether this association is driven by changes in breast tissue composition (BTC) prior to adulthood remains unclear.

METHODS

We used multivariable linear regression models to examine whether SES at birth is associated with BTC in adolescence and adulthood using data from a New York City cohort of daughters (n = 165, 11-20 years) and mothers (n = 160, 29-55 years). We used maternal-reported data on daughters' household income and maternal education at birth, analyzed individually and in combination (SES index). Women also reported their own mothers' education at birth. We used optical spectroscopy to evaluate BTC measures that positively (water content, collagen content, optical index) and negatively (lipid content) correlate with mammographic breast density, a recognized breast cancer risk factor.

RESULTS

Being in the highest versus lowest category of the SES index was associated with lower lipid content [βadjusted (βadj) = -0.80; 95% confidence interval (CI), -1.30 to -0.31] and higher collagen content (βadj = 0.54; 95% CI, 0.09-0.99) in adolescence. In women with a body mass index (BMI) <30 kg/m2, higher maternal education at birth (≥ vs. < high school degree) was associated with lower lipid content (βadj = -0.57; 95% CI, -0.97 to -0.17), higher water content (βadj = 0.70; 95% CI, 0.26-1.14), and higher optical index (βadj = 0.53; 95% CI, 0.10-0.95).

CONCLUSIONS

This study supports that SES at birth is associated with BTC in adolescence and adulthood, although the latter association may depend on adult BMI.

IMPACT

Further research is needed to identify the socially patterned early life factors influencing BTC.

Association between estimated cardiorespiratory fitness and breast cancer: a prospective cohort study

OBJECTIVE

To examine the association between cardiorespiratory fitness (CRF) and the risk of breast cancer in postmenopausal women.

METHODS

This study used data from 17 840 cancer-free postmenopausal women with a CRF assessment from the UK Biobank. High estimated CRF (eCRF) was categorised as being >80th percentile within 10-year age bands. Fine and Gray regression was used to examine the association between eCRF and breast cancer risk, accounting for both non-breast cancer diagnoses and all-cause mortality as competing risks. Age was used as the time scale. Several different models were produced, including those adjusting for known breast cancer risk factors, and stratified by measures of body fat (body mass index and per cent body fat).

RESULTS

Over a median follow-up of 11.0 years there were 529 cases of invasive breast cancer, 1623 cases of non-breast cancer disease and 241 deaths. With adjustment for breast cancer risk factors, high eCRF was associated with a 24% (subdistribution HR (SDHR) 0.76, 95% CI 0.60 to 0.97) lower risk of breast cancer. When stratified by measures of body fat, we found evidence of effect measure modification. Mainly, having high eCRF was only associated with a lower risk of breast cancer among those classified as having overweight/obesity (SDHR 0.33, 95% CI 0.11 to 1.01) or percentage body fat above the 1st quintile (SDHR 0.65, 95% CI 0.45 to 0.94).

CONCLUSION

Having higher CRF may be a protective factor against breast cancer in postmenopausal women but only for women with elevated body fat.

Biological and clinical implications of early-onset cancers: A unique subtype

In recent years, the incidence of cancers is continuously increasing in young adults. Early-onset cancer (EOC) is usually defined as patients with cancers under the age of 50, and may represent a unique subgroup due to its special disease features. Overall, EOCs often initiate at a young age, present as a better physical performance but high degree of malignancy. EOCs also share common epidemiological and hereditary risk factors. In this review, we discuss several representative EOCs which were well studied previously. By revealing their clinical and molecular similarities and differences, we consider the group of EOCs as a unique subtype compared to ordinary cancers. In consideration of EOC as a rising threat to human health, more researches on molecular mechanisms, and large-scale, prospective clinical trials should be carried out to further translate into improved outcomes.

Geographical Variation in Social Determinants of Female Breast Cancer Mortality Across US Counties

Importance

Breast cancer mortality is complex and traditional approaches that seek to identify determinants of mortality assume that their effects on mortality are stationary across geographic space and scales.

Objective

To identify geographic variation in the associations of population demographics, environmental, lifestyle, and health care access with breast cancer mortality at the US county-level.

Design, Setting, and Participants

This geospatial cross-sectional study used data from the Surveillance, Epidemiology, and End Results (SEER) database on adult female patients with breast cancer. Statistical and spatial analysis was completed using adjusted mortality rates from 2015 to 2019 for 2176 counties in the US. Data were analyzed July 2022.

Exposures

County-level population demographics, environmental, lifestyle, and health care access variables were obtained from open data sources.

Main Outcomes and Measures

Model coefficients describing the association between 18 variables and age-adjusted breast cancer mortality rate. Compared with a multivariable linear regression (OLS), multiscale geographically weighted regression (MGWR) relaxed the assumption of spatial stationarity and allowed for the magnitude, direction, and significance of coefficients to change across geographic space.

Results

Both OLS and MGWR models agreed that county-level age-adjusted breast cancer mortality rates were significantly positively associated with obesity (OLS: β, 1.21; 95% CI, 0.88 to 1.54; mean [SD] MGWR: β, 0.72 [0.02]) and negatively associated with proportion of adults screened via mammograms (OLS: β, -1.27; 95% CI, -1.70 to -0.84; mean [SD] MGWR: β, -1.07 [0.16]). Furthermore, the MGWR model revealed that these 2 determinants were associated with a stationary effect on mortality across the US. However, the MGWR model provided important insights on other county-level factors differentially associated with breast cancer mortality across the US. Both models agreed that smoking (OLS: β, -0.65; 95% CI, -0.98 to -0.32; mean [SD] MGWR: β, -0.75 [0.92]), food environment index (OLS: β, -1.35; 95% CI, -1.72 to -0.98; mean [SD] MGWR: β, -1.69 [0.70]), exercise opportunities (OLS: β, -0.56; 95% CI, -0.91 to -0.21; mean [SD] MGWR: β, -0.59 [0.81]), racial segregation (OLS: β, -0.60; 95% CI, -0.89 to -0.31; mean [SD] MGWR: β, -0.47 [0.41]), mental health care physician ratio (OLS: β, -0.93; 95% CI, -1.44 to -0.42; mean [SD] MGWR: β, -0.48 [0.92]), and primary care physician ratio (OLS: β, -1.46; 95% CI, -2.13 to -0.79; mean [SD] MGWR: β, -1.06 [0.57]) were negatively associated with breast cancer mortality, and that light pollution was positively associated (OLS: β, 0.48; 95% CI, 0.24 to 0.72; mean [SD] MGWR: β, 0.27 [0.04]). But in the MGWR model, the magnitude of effect sizes and significance varied across geographical regions. Inversely, the OLS model found that disability was not a significant variable for breast cancer mortality, yet the MGWR model found that it was significantly positively associated in some geographical locations.

Conclusions and Relevance

This cross-sectional study found that not all social determinants associated with breast cancer mortality are spatially stationary and provides spatially explicit insights for public health practitioners to guide geographically targeted interventions.

Trends in Diet and Cancer Research: A Bibliometric and Visualization Analysis

Diet plays a critical role for patients across the cancer continuum. The World Cancer Research Fund International and the American Cancer Society have published evidence supporting the role of nutrition in cancer prevention. We conducted an analysis of the literature on dietary nutrients and cancer to uncover opportunities for future research. The objective of the bibliometric analysis was to describe trends in peer-reviewed publications on dietary components and cancer and to highlight research gaps. PubMed was queried for manuscripts with diet- and cancer-related keywords and Medical Subject Headings (MeSH) terms. Metadata covering 99,784 publications from 6469 journals were analyzed to identify trends since 1970 on diet topics across 19 tumor types. Publications focused largely on breast, colorectal, and liver cancer, with fewer papers linking diet with other cancers such as brain, gallbladder, or ovarian. With respect to "unhealthy" diets, many publications focused on high-fat diets and alcohol consumption. The largest numbers of publications related to "healthy" diets examined the Mediterranean diet and the consumption of fruits and vegetables. These findings highlight the need for additional research focused on under-investigated cancers and dietary components, as well as dietary studies during cancer therapy and post-therapy, which may help to prolong survivorship.

Surviving the Test of Time: A Young Patient's Triumph Over Early-Onset Invasive Ductal Carcinoma and Its Recurrence a Decade Later

Breast cancer is a complex, heterogeneous disease with diverse clinical presentations and variable outcomes. In this report, we provide a detailed analysis of a case involving a 22-year-old woman diagnosed with invasive ductal carcinoma, highlighting the difficulties of managing breast cancer in young patients. Through the examination of this patient's 10-year journey, from the initial diagnosis to surgery, adjuvant therapy, and recurrence, we underline the crucial role of early detection, personalised treatment, and interdisciplinary cooperation in optimising patient outcomes. Overall, the case study serves as a compelling narrative, effectively highlighting the aggressive nature of breast cancer in younger individuals and underscoring the need to provide care that addresses the multifaceted dimensions of this disease.

Influence of analytic methods, data sources, and repeated measurements on the population attributable fraction of lifestyle risk factors

Population attributable risk (PAR%) reflects the preventable fraction of disease. However, PAR% estimates of cancer have shown large variation across populations, methods, data sources, and timing of measurements. Three statistical methods to estimate PAR% were identified from a systematic literature review: the Levin's formula, the comparative incidence rate method, and the comparative risk assessment method. We compared the variations in PAR% of postmenopausal breast cancer in the Nurses' Health Study to evaluate the influence by method choice, source of prevalence data, use of single vs repeated exposure measurements, and potential joint effects of obesity, alcohol, physical activity, fruit and vegetable intake. Across models of the three methods, the estimated PAR% using repeated measurements were higher than that using baseline measurement; overall PAR% for the baseline, simple update, and cumulative average models were 13.8%, 21.1%, 18.6% by Levin's formula; 13.7%, 28.0%, 31.2% by comparative risk assessment; and 17.4%, 25.2%, 29.3% by comparative incidence rate method. The estimated PAR% of the combination of multiple risk factors was higher than the product of the individual PAR%: 18.9% when assuming independence and 31.2% when considering the risk factors jointly. The three methods provided similar PAR% based on the same data source, timing of measurements, and target populations. However, sizable increases in the PAR% were observed for repeated measures over a single measure and for calculations based on achieving all recommendations jointly rather than individually.

Associations of height, body mass index, and weight gain with breast cancer risk in carriers of a pathogenic variant in BRCA1 or BRCA2: the BRCA1 and BRCA2 Cohort Consortium

INTRODUCTION

Height, body mass index (BMI), and weight gain are associated with breast cancer risk in the general population. It is unclear whether these associations also exist for carriers of pathogenic variants in the BRCA1 or BRCA2 genes.

PATIENTS AND METHODS

An international pooled cohort of 8091 BRCA1/2 variant carriers was used for retrospective and prospective analyses separately for premenopausal and postmenopausal women. Cox regression was used to estimate breast cancer risk associations with height, BMI, and weight change.

RESULTS

In the retrospective analysis, taller height was associated with risk of premenopausal breast cancer for BRCA2 variant carriers (HR 1.20 per 10 cm increase, 95% CI 1.04-1.38). Higher young-adult BMI was associated with lower premenopausal breast cancer risk for both BRCA1 (HR 0.75 per 5 kg/m2, 95% CI 0.66-0.84) and BRCA2 (HR 0.76, 95% CI 0.65-0.89) variant carriers in the retrospective analysis, with consistent, though not statistically significant, findings from the prospective analysis. In the prospective analysis, higher BMI and adult weight gain were associated with higher postmenopausal breast cancer risk for BRCA1 carriers (HR 1.20 per 5 kg/m2, 95% CI 1.02-1.42; and HR 1.10 per 5 kg weight gain, 95% CI 1.01-1.19, respectively).

CONCLUSION

Anthropometric measures are associated with breast cancer risk for BRCA1 and BRCA2 variant carriers, with relative risk estimates that are generally consistent with those for women from the general population.

The association of a combined healthy lifestyle with the risk of postmenopausal breast cancer subtypes in the Netherlands Cohort Study

The association between combined healthy lifestyle and postmenopausal breast cancer risk has been studied in various cohort studies, but only few evaluated the association with estrogen/progesterone (ER/PR) receptor subtypes of breast cancer, with inconsistent results. The relationship of a healthy lifestyle score (HLS) with risk of postmenopausal breast cancer (subtypes) was investigated in the Netherlands Cohort Study. In 1986, 62,573 women aged 55-69 years provided information on dietary and lifestyle habits. The HLS was derived from information on smoking, body mass index, physical activity, Mediterranean diet adherence, and alcohol intake. After 20.3 years of follow-up, multivariable case-cohort analyses were based on 2321 incident breast cancer cases, and 1665 subcohort members with complete data on lifestyles and confounders. The HLS showed a statistically significant inverse relationship with postmenopausal breast cancer risk, in a linear fashion. A one-point increment of the HLS was accompanied by a Hazard Ratio (HR) reduction of 20% for overall breast cancer. The associations between HLS and risk of ER/PR breast cancer subtypes were also significantly inverse, except for ER- breast cancer where the inverse association did not reach statistical significance. Per HLS-increment of one point, the HR reduction ranged from 14% for ER-breast cancer to 29% for ER + PR- breast cancer. These findings suggest that adhering to a combination of healthy modifiable lifestyle factors may substantially reduce the risk of overall postmenopausal breast cancer and its hormone receptor subtypes.

Objective Measurement of Physical Activity and Sedentary Behavior in Patients with Chronic Obstructive Pulmonary Disease: Points to Keep in Mind during Evaluations

Objective measurement methods using accelerometers have become the mainstream approach for evaluating physical activity (PA) and sedentary behavior (SB). However, several problems face the objective evaluation of PA and SB in patients with chronic obstructive pulmonary disease (COPD). For example, indicators of PA differ depending on whether the accelerometer detects the kind of activity on the one hand, or its intensity on the other. Measured data are also strongly influenced by environmental factors (weather, season, employment status, etc.) and methodological factors (days with uncommon activities, non-wearing time, minimum required wearing time per day, minimum number of valid days required, etc.). Therefore, adjusting for these factors is required when evaluating PA or SB, especially when evaluating the effects of intervention. The exclusion of sleeping time, unification of total measurement time, and minimization of the required wearing time per day might be more important for the evaluation of ST than for evaluating PA. The lying-down-time-to-sitting-time ratio was shown to be larger in COPD patients than in healthy subjects. In this review, we clarified the problems encountered during objective evaluations of PA and SB in patients with COPD and encouraged investigators to recognize the presence of these problems and the importance of adjusting for them.

Linking Physical Activity to Breast Cancer Risk via Inflammation, Part 1: The Effect of Physical Activity on Inflammation

The protective effect of physical activity on breast cancer incidence may partially be mediated by inflammation. Systematic searches of Medline, EMBASE, and SPORTDiscus were performed to identify intervention studies, Mendelian randomization studies, and prospective cohort studies that examined the effects of physical activity on circulating inflammatory biomarkers in adult women. Meta-analyses were performed to generate effect estimates. Risk of bias was assessed, and the Grading of Recommendations Assessment, Development, and Evaluation system was used to determine the overall quality of the evidence. Thirty-five intervention studies and one observational study met the criteria for inclusion. Meta-analyses of randomized controlled trials (RCT) indicated that, compared with control groups, exercise interventions reduced levels of C-reactive protein (CRP) [standardized mean difference (SMD) = -0.27, 95% confidence interval (CI) = -0.62 to 0.08), tumor necrosis factor alpha (TNFα, SMD = -0.63, 95% CI = -1.04 to -0.22), interleukin-6 (IL6, SMD = -0.55, 95% CI = -0.97 to -0.13) and leptin (SMD = -0.50, 95% CI = -1.10 to 0.09). Owing to heterogeneity in effect estimates and imprecision, evidence strength was graded as low (CRP, leptin) or moderate (TNFα and IL6). High-quality evidence indicated that exercise did not change adiponectin levels (SMD = 0.01, 95% CI = -0.14 to 0.17). These findings provide support for the biological plausibility of the first part of the physical activity-inflammation-breast cancer pathway.

Linking Physical Activity to Breast Cancer via Inflammation, Part 2: The Effect of Inflammation on Breast Cancer Risk

This review synthesized and appraised the evidence for an effect of inflammation on breast cancer risk. Systematic searches identified prospective cohort and Mendelian randomization studies relevant to this review. Meta-analysis of 13 biomarkers of inflammation were conducted to appraise the evidence for an effect breast cancer risk; we examined the dose-response of these associations. Risk of bias was evaluated using the ROBINS-E tool and the quality of evidence was appraised with Grading of Recommendations Assessment, Development, and Evaluation. Thirty-four observational studies and three Mendelian randomization studies were included. Meta-analysis suggested that women with the highest levels of C-reactive protein (CRP) had a higher risk of developing breast cancer [risk ratio (RR) = 1.13; 95% confidence interval (CI), 1.01-1.26] compared with women with the lowest levels. Women with highest levels of adipokines, particularly adiponectin (RR = 0.76; 95% CI, 0.61-0.91) had a reduced breast cancer risk, although this finding was not supported by Mendelian randomization analysis. There was little evidence of an effect of cytokines, including TNFα and IL6, on breast cancer risk. The quality of evidence for each biomarker ranged from very low to moderate. Beyond CRP, the published data do not clearly support the role of inflammation in the development of breast cancer.

Obesity, the Adipose Organ and Cancer in Humans: Association or Causation?

Epidemiological observations, experimental studies and clinical data show that obesity is associated with a higher risk of developing different types of cancer; however, proof of a cause-effect relationship that meets the causality criteria is still lacking. Several data suggest that the adipose organ could be the protagonist in this crosstalk. In particular, the adipose tissue (AT) alterations occurring in obesity parallel some tumour behaviours, such as their theoretically unlimited expandability, infiltration capacity, angiogenesis regulation, local and systemic inflammation and changes to the immunometabolism and secretome. Moreover, AT and cancer share similar morpho-functional units which regulate tissue expansion: the adiponiche and tumour-niche, respectively. Through direct and indirect interactions involving different cellular types and molecular mechanisms, the obesity-altered adiponiche contributes to cancer development, progression, metastasis and chemoresistance. Moreover, modifications to the gut microbiome and circadian rhythm disruption also play important roles. Clinical studies clearly demonstrate that weight loss is associated with a decreased risk of developing obesity-related cancers, matching the reverse-causality criteria and providing a causality correlation between the two variables. Here, we provide an overview of the methodological, epidemiological and pathophysiological aspects, with a special focus on clinical implications for cancer risk and prognosis and potential therapeutic interventions.

Changes in mammographic density and risk of breast cancer among a diverse cohort of women undergoing mammography screening

PURPOSE

Mammographic density (MD) is a strong breast cancer risk factor. MD may change over time, with potential implications for breast cancer risk. Few studies have assessed associations between MD change and breast cancer in racially diverse populations. We investigated the relationships between MD and MD change over time and breast cancer risk in a large, diverse screening cohort.

MATERIALS AND METHODS

We retrospectively analyzed data from 8462 women who underwent ≥ 2 screening mammograms from Sept. 2010 to Jan. 2015 (N = 20,766 exams); 185 breast cancers were diagnosed 1-7 years after screening. Breast percent density (PD) and dense area (DA) were estimated from raw digital mammograms (Hologic Inc.) using LIBRA (v1.0.4). For each MD measure, we modeled breast density change between two sequential visits as a function of demographic and risk covariates. We used Cox regression to examine whether varying degrees of breast density change were associated with breast cancer risk, accounting for multiple exams per woman.

RESULTS

PD at any screen was significantly associated with breast cancer risk (hazard ratio (HR) for PD = 1.03 (95% CI [1.01, 1.05], p < 0.0005), but neither change in breast density nor more extreme than expected changes in breast density were associated with breast cancer risk. We found no evidence of differences in density change or breast cancer risk due to density change by race. Results using DA were essentially identical.

CONCLUSIONS

Using a large racially diverse cohort, we found no evidence of association between short-term change in MD and risk of breast cancer, suggesting that short-term MD change is not a strong predictor for risk.

Associations of body fat mass and fat-free mass with breast cancer incidence in postmenopausal women: A Danish prospective cohort study

PURPOSE

Previous studies have established associations between body mass index and breast cancer, but fat mass is a more direct measure of the amount of fat tissue in the body than body mass index. This study examined the association between body fat mass, fat-free mass, and other anthropometric measures and breast cancer in postmenopausal women according to use of hormone replacement therapy (HRT).

METHODS

From the Danish Diet, Cancer and Health cohort established during 1993-1997, 24,219 postmenopausal women were included who had anthropometric and bioimpedance measurements performed by a laboratory technician at baseline. Information on breast cancer incidence (outcome), other cancer diagnoses, and vital status (censoring variables) through 2016 was obtained from nationwide registers. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CIs) while adjusting for known breast cancer risk factors and stratifying by HRT use and running age.

RESULTS

During a total of 431,104 person-years, 1919 women developed breast cancer. Among never-users of HRT, the HR for breast cancer at or after age 65 years was 1.06 (95% CI, 1.03-1.08) per 1 kg/m² higher body fat mass index (BFMI), and 1.30 (95% CI, 1.14-1.47) per 10% higher body fat percentage. The corresponding HRs for breast cancer before age 65 years were close to unity. The HRs were 1.11 (95% CI, 1.02-1.21) and 1.17 (95% CI, 1.10-1.23) for each 1 kg/m² increase in fat-free mass index, respectively, for breast cancer below and above age 65 years. Mutual adjustment attenuated the HRs for BFMI and body fat percentage, whereas the HRs for fat-free mass index were largely unaffected. Among ever-users of HRT, there was no statistical significant association between any of the body composition measures and breast cancer incidence in the two age groups.

CONCLUSIONS

Among postmenopausal women who never used HRT, BFMI was associated with breast cancer in women aged 65 years or older. Fat-free mass index was found to be more strongly associated with postmenopausal breast cancer incidence than BFMI independently of age in never-users of HRT.

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.

Monitoring and Modulating Diet and Gut Microbes to Enhance Response and Reduce Toxicity to Cancer Treatment

The gut microbiome comprises a diverse array of microbial species that have been shown to dynamically modulate host immunity both locally and systemically, as well as contribute to tumorigenesis. In this review, we discuss the scientific evidence on the role that gut microbes and diet play in response and toxicity to cancer treatment. We highlight studies across multiple cancer cohorts that have shown an association between particular gut microbiome signatures and an improved response to immune checkpoint blockade, chemotherapy, and adoptive cell therapies, as well as the role of particular microbes in driving treatment-related toxicity and how the microbiome can be modulated through strategies, such as fecal transplant. We also summarize the current literature that implicate high fiber and ketogenic diets in improved response rates to immunotherapy and chemotherapy, respectively. Finally, we discuss the relevance of these findings in the context of patient care, advocate for a holistic approach to cancer treatment, and comment on the next frontier of targeted gut and tumor microbiome modulation through novel therapeutics, dietary intervention, and precision-medicine approaches.

Obesity and Cancer: A Current Overview of Epidemiology, Pathogenesis, Outcomes, and Management

BACKGROUND

Obesity or excess body fat is a major global health challenge that has not only been associated with diabetes mellitus and cardiovascular disease but is also a major risk factor for the development of and mortality related to a subgroup of cancer. This review focuses on epidemiology, the relationship between obesity and the risk associated with the development and recurrence of cancer and the management of obesity.

METHODS

A literature search using PubMed and Google Scholar was performed and the keywords 'obesity' and cancer' were used. The search was limited to research papers published in English prior to September 2022 and focused on studies that investigated epidemiology, the pathogenesis of cancer, cancer incidence and the risk of recurrence, and the management of obesity.

RESULTS

About 4-8% of all cancers are attributed to obesity. Obesity is a risk factor for several major cancers, including post-menopausal breast, colorectal, endometrial, kidney, esophageal, pancreatic, liver, and gallbladder cancer. Excess body fat results in an approximately 17% increased risk of cancer-specific mortality. The relationship between obesity and the risk associated with the development of cancer and its recurrence is not fully understood and involves altered fatty acid metabolism, extracellular matrix remodeling, the secretion of adipokines and anabolic and sex hormones, immune dysregulation, and chronic inflammation. Obesity may also increase treatment-related adverse effects and influence treatment decisions regarding specific types of cancer therapy. Structured exercise in combination with dietary support and behavior therapy are effective interventions. Treatment with glucagon-like peptide-1 analogues and bariatric surgery result in more rapid weight loss and can be considered in selected cancer survivors.

CONCLUSIONS

Obesity increases cancer risk and mortality. Weight-reducing strategies in obesity-associated cancers are important interventions as a key component of cancer care. Future studies are warranted to further elucidate the complex relationship between obesity and cancer with the identification of targets for effective interventions.

Associations between overall, healthful, and unhealthful low-fat dietary patterns and breast cancer risk in a Mediterranean cohort: The SUN project

OBJECTIVES

Dietary patterns may have a greater influence on human health than individual foods or nutrients, and they are also of substantial interest in the field of breast cancer prevention. Beyond the adequate balance of macronutrients, evidence indicates that the quality of macronutrient sources may play an important role in health outcomes. We sought to examine the relationship between healthful and unhealthful low-fat dietary patterns in relation to breast cancer.

METHODS

We used observational data from a Mediterranean cohort study (the Seguimiento Universidad de Navarra project). We prospectively followed 10 930 middle-aged women initially free of breast cancer during a median follow-up of 12.1 y. We calculated an overall, an unhealthful, and a healthful low-fat diet score, based on a previously validated 136-item food frequency questionnaire and grouped participants into tertiles. Incident breast cancer-overall and stratified by menopausal status-was the primary outcome. It was self-reported by participants and confirmed based on medical reports or consultation of the National Death Index. We used multivariable Cox regression models adjusted for potential confounders.

RESULTS

During 123 297 person-years of follow-up, 150 cases of incident breast cancer were confirmed. No significant associations were observed for overall or premenopausal breast cancer. For postmenopausal women, we observed a significant association for moderate adherence to the unhealthful low-fat dietary score and postmenopausal breast cancer (comparing tertile 2 to tertile 1; hazard ratio = 2.18; 95% confidence interval, 1.15-4.13).

CONCLUSIONS

In conclusion, no clear associations were observed, although more research is needed to address the association between an unhealthful dietary pattern and postmenopausal breast cancer risk.

Physical activity and breast cancer survival: results from the Nurses' Health Studies

BACKGROUND

Physical activity is generally associated with better outcomes following diagnosis; however, few studies have evaluated change in pre- to postdiagnosis activity and repeated measures of activity by intensity and type.

METHODS

We evaluated physical activity and survival following a breast cancer diagnosis in the Nurses' Health Study and Nurses' Health Study II (n = 9308 women, n = 1973 deaths). Physical activity was evaluated as updated cumulative average of metabolic equivalent of task (MET)-h/wk (assigned per activity based on duration and intensity) and change in pre- to postdiagnosis activity. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Higher postdiagnosis activity was inversely associated with breast cancer-specific mortality in categories from ≥9 MET-h/wk (vs <3 MET h/wk, HR≥9 to <18 = 0.74 [95% CI = 0.55 to 0.99]; HR≥27 = 0.69 [95% CI = 0.50 to 0.95]; Ptrend = .04) and all-cause mortality from ≥3 MET-h/wk (HR≥3 to <9 = 0.73 [95% CI = 0.61 to 0.88]; HR≥27 = 0.51 [95% CI = 0.41 to 0.63]; Ptrend < .001). Associations were predominantly observed for estrogen receptor-positive tumors and in postmenopausal women. Walking was associated with lower risk of all-cause mortality (≥9 vs <3 MET-h/wk, HR= 0.69 [95% CI = 0.57 to 0.84]) as was strength training. Relative to stable activity pre- to postdiagnosis (±3 MET-h/wk), increases from ≥3 to 9 MET-h/wk were associated with lower all-cause mortality risk (Ptrend < .001). Results were robust to adjustment for prediagnosis physical activity.

CONCLUSIONS

Physical activity was associated with lower risk of death following diagnosis. Increased pre- to postdiagnosis activity corresponding to at least 1-3 h/wk of walking was associated with lower risk of death. These results provide further impetus for women to increase their activity after a breast cancer diagnosis, though reverse causation cannot be fully excluded.

Linking Physical Activity to Breast Cancer Risk via Insulin/Insulin-Like Growth Factor Signaling System, Part 1: The Effect of Physical Activity on the Insulin/Insulin-Like Growth Factor Signaling System

Physical activity may reduce the risk of developing breast cancer via its effect on the insulin/insulin-like growth factor (IGF) signaling system. A systematic review searched for randomized controlled trials (RCT), Mendelian randomization and prospective cohort studies that examined the effects of physical activity on insulin/IGF signaling [IGFs, their binding proteins (IGFBP), and markers of insulin resistance] in adult women. Meta-analyses were performed to generate effect estimates. Risk of bias was assessed, and the Grading of Recommendations Assessment, Development, and Evaluation system used to determine the overall quality of the evidence. Fifty-eight RCTs met our inclusion criteria, no observational or Mendelian randomization studies met the criteria for inclusion. Meta-analyses indicated that physical activity interventions (vs. control) reduced fasting insulin, the Homeostatic Model Assessment for Insulin Resistance and fasting glucose. Physical activity increased IGF-1, but there was no clear effect on IGFBP-3 or the ratio of IGF-1:IGFBP-3. Strong evidence was only established for fasting insulin and insulin resistance. Further research is needed to examine the effect of physical activity on C-peptide and HBA1c in women. Reductions in fasting insulin and insulin resistance following exercise suggest some biological plausibility of the first part of the physical activity-insulin/IGF signaling-breast cancer pathway. See related article by Drummond et al., p. 2116.

Promote Community Engagement in Participatory Research for Improving Breast Cancer Prevention: The P.I.N.K. Study Framework

Breast cancer (BC) has overtaken lung cancer as the most common cancer in the world and the projected incidence rates show a further increase. Early detection through population screening remains the cornerstone of BC control, but a progressive change from early diagnosis only-based to a personalized preventive and risk-reducing approach is widely debated. Risk-stratification models, which also include personal lifestyle risk factors, are under evaluation, although the documentation burden to gather population-based data is relevant and traditional data collection methods show some limitations. This paper provides the preliminary results from the analysis of clinical data provided by radiologists and lifestyle data collected using self-administered questionnaires from 5601 post-menopausal women. The weight of the combinations of women's personal features and lifestyle habits on the BC risk were estimated by combining a model-driven and a data-driven approach to analysis. The weight of each factor on cancer occurrence was assessed using a logistic model. Additionally, communities of women sharing common features were identified and combined in risk profiles using social network analysis techniques. Our results suggest that preventive programs focused on increasing physical activity should be widely promoted, in particular among the oldest women. Additionally, current findings suggest that pregnancy, breast-feeding, salt limitation, and oral contraception use could have different effects on cancer risk, based on the overall woman's risk profile. To overcome the limitations of our data, this work also introduces a mobile health tool, the Dress-PINK, designed to collect real patients' data in an innovative way for improving women's response rate, data accuracy, and completeness as well as the timeliness of data availability. Finally, the tool provides tailored prevention messages to promote critical consciousness, critical thinking, and increased health literacy among the general population.