WHO-recommended levels of physical activity in relation to mammographic breast density, mammographic tumor appearance, and mode of detection of breast cancer.

BACKGROUND: Despite known benefits of physical activity in reducing breast cancer risk, its impact on mammographic characteristics remain unclear and understudied. This study aimed to investigate associations between pre-diagnostic physical activity and mammographic features at breast cancer diagnosis, specifically mammographic breast density (MBD) and mammographic tumor appearance (MA), as well as mode of cancer detection (MoD). METHODS: Physical activity levels from study baseline (1991-1996) and mammographic information from the time of invasive breast cancer diagnosis (1991-2014) of 1116 women enrolled in the Malmö Diet and Cancer Study cohort were used. Duration and intensity of physical activity were assessed according to metabolic equivalent of task hours (MET-h) per week, or World Health Organization (WHO) guideline recommendations. MBD was dichotomized into low-moderate or high, MA into spiculated or non-spiculated tumors, and MoD into clinical or screening detection. Associations were investigated through logistic regression analyses providing odds ratios (OR) with 95% confidence intervals (CI) in crude and multivariable-adjusted models. RESULTS: In total, 32% of participants had high MBD at diagnosis, 37% had non-spiculated MA and 50% had clinical MoD. Overall, no association between physical activity and MBD was found with increasing MET-h/week or when comparing women who exceeded WHO guidelines to those subceeding recommendations (ORadj 1.24, 95% CI 0.78-1.98). Likewise, no differences in MA or MoD were observed across categories of physical activity. CONCLUSIONS: No associations were observed between pre-diagnostic physical activity and MBD, MA, or MoD at breast cancer diagnosis. While physical activity is an established breast cancer prevention strategy, it does not appear to modify mammographic characteristics or screening detection.

Baseline breast tissue characteristics determine the effect of tamoxifen on mammographic density change.

Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1-20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR.

Impact of type 2 diabetes on complications after primary breast cancer surgery: Danish population-based cohort study.

BACKGROUND: Knowledge is sparse on the impact of type 2 diabetes (T2D) on surgical outcomes after breast cancer surgery. This study investigated the association between T2D and risk of complications after primary breast cancer surgery, and evaluated the biological interaction between T2D and co-morbidities. METHODS: Using the Danish Breast Cancer Group clinical database, a cohort of all Danish women diagnosed with early-stage breast cancer during 1996-2022 was created. All patients underwent mastectomy or breast-conserving surgery. Information on prevalent T2D was collected from Danish medical and prescription registries. Surgical complications were defined as hospital diagnoses for medical or surgical complications developing within 30 days after primary breast cancer surgery. The 30-day cumulative incidence proportion of complications was calculated, and Cox regression was used to estimate HRs. Interaction contrasts were computed to determine the additive interaction between T2D and co-morbidities on the incidence rate of complications. RESULTS: Among 98 589 women with breast cancer, 6332 (6.4%) had T2D at breast cancer surgery. Overall, 1038 (16.4%) and 9861 (10.7%) women with and without T2D developed surgical complications, yielding cumulative incidence proportions of 16 (95% c.i. 15 to 17) and 11 (10 to 11)% respectively, and a HR of 1.43 (95% c.i. 1.34 to 1.53). The incidence rate of surgical complications explained by the interaction of T2D with moderate and severe co-morbidity was 21 and 42%, respectively. CONCLUSION: Women with breast cancer and T2D had a higher risk of complications after primary breast cancer surgery than those without T2D. A synergistic effect of T2D and co-morbidity on surgical complications can explain this association.

Changes in experienced quality of oncological cancer care during the COVID-19 pandemic based on patient reported outcomes - a cross-sectional study.

AIM: The study aims to investigate the impact of the COVID-19 pandemic on cancer patients' perceptions of the quality of their oncological treatment and care. BACKGROUND: The COVID-19 pandemic disrupted healthcare delivery and oncological resources were repurposed, potentially leading to prolonged treatment and reduced access to innovative therapies and clinical trials. Still, little is known about how patients perceived the quality of their treatment. METHODS: A cross-sectional study was conducted in the spring of 2020 among cancer patients at the Department of Oncology, Aarhus University Hospital and Rigshospitalet, Denmark. Patients were invited to complete an online questionnaire on clinical, socioeconomic, emotional, behavioural, and quality-related aspects of oncological cancer care. Patients who experienced reduced treatment quality and those who reported no or slight reductions were compared using multiple logistic regression, exploring the associations with patient characteristics, behaviours, and fear of cancer progression or recurrence. RESULTS: A total of 2,040/5,372 patients experienced changes in their treatment plans during the pandemic, and 1,570/5,372 patients experienced reduced treatment quality, with 236 reporting a high degree of reduction. Patients with breast, head and neck, and upper gastrointestinal cancers were more likely to experience reduced treatment quality. Altered interactions with healthcare providers, along with isolation, lack of social support, and heightened fear of cancer progression, were significant risk factors for experiencing reduced cancer care quality. INTERPRETATION: We identified subgroups of cancer patients needing targeted communication and care during health crises affecting cancer treatment. The findings underscore the importance of safeguarding the needs of vulnerable patient populations in future healthcare emergencies.

Effects of tamoxifen on normal breast tissue histological composition: Results from a randomised six-arm placebo-controlled trial in healthy women.

Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to "no dose" (0-1 mg), "low-dose" (2.5-5 mg) or "high-dose" (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen.

Side effects of low-dose tamoxifen: results from a six-armed randomised controlled trial in healthy women.

BACKGROUND: Adherence to adjuvant tamoxifen therapy is suboptimal, and acceptance of tamoxifen for primary prevention is poor. Published results indicate effect of low-dose tamoxifen therapy. Using questionnaire data from a randomised controlled trial, we describe side effects of standard and low-dose tamoxifen in healthy women. METHODS: In the KARISMA trial, 1440 healthy women were randomised to 6 months of daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. Participants completed a 48-item, five-graded Likert score symptom questionnaire at baseline and follow-up. Linear regression models were used to identify significant changes in severity levels across doses and by menopausal status. RESULTS: Out of 48 predefined symptoms, five were associated with tamoxifen exposure (hot flashes, night sweats, cold sweats, vaginal discharge and muscle cramps). When comparing these side effects in premenopausal women randomised to low doses (2.5, 5 mg) versus high doses (10, 20 mg), the mean change was 34% lower in the low-dose group. No dose-dependent difference was seen in postmenopausal women. CONCLUSIONS: Symptoms related to tamoxifen therapy are influenced by menopausal status. Low-dose tamoxifen, in contrast to high-dose, was associated with less pronounced side effects, a finding restricted to premenopausal women. Our findings give new insights which may influence future dosing strategies of tamoxifen in both the adjuvant and preventive settings. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03346200.

Breast cancer and incidence of type 2 diabetes mellitus: a systematic review and meta-analysis.

PURPOSE: Breast cancer and its treatments may increase the risk of type 2 diabetes (T2D). We conducted a systematic review and meta-analysis to investigate the association between breast cancer and the incidence of T2D overall, and according to breast cancer treatments. METHODS: We searched PubMed, Embase and references of relevant papers for studies on breast cancer, breast cancer treatment, and subsequent T2D risk. Using random-effects models, we calculated effect estimates and associated 95% confidence intervals of the association between breast cancer, adjuvant breast cancer treatments (i.e., endocrine therapy (tamoxifen, aromatase inhibitors, and combined) and chemotherapy), and subsequent T2D. We used funnel plots to assess publication bias. RESULTS: Among 15 eligible studies, 10 reported on T2D risk after breast cancer, chemotherapy, or endocrine therapy; five studies investigated more than one association. Compared with patients without breast cancer, those with breast cancer and those who received any endocrine therapy had elevated risk of incident T2D (EE = 1.23, 95% CI = 1.13-1.33 and EE = 1.23, 95% CI = 1.16-1.32, respectively). Among breast cancer patients only, the risk of T2D was higher for those who received tamoxifen compared with those who did not receive tamoxifen (EE = 1.28, 95% CI = 1.18-1.38). Due to few studies, analyses investigating T2D risk after treatment with aromatase inhibitors or chemotherapy were inconclusive. CONCLUSION: Our findings suggest an elevated risk of T2D in breast cancer survivors, particularly after tamoxifen therapy. Further research is needed to determine the impact of aromatase inhibitors, and chemotherapy on the incidence of T2D after breast cancer.

Caveolin-1 genotypes as predictor for locoregional recurrence and contralateral disease in breast cancer.

PURPOSE: Caveolin-1 (CAV1) has been implicated in breast cancer oncogenesis and metastasis and may be a potential prognosticator, especially for non-distant events. CAV1 functions as a master regulator of membrane transport and cell signaling. Several CAV1 SNPs have been linked to multiple cancers, but the prognostic impact of CAV1 SNPs in breast cancer remains unclear. Here, we investigated CAV1 polymorphisms in relation to clinical outcomes in breast cancer. METHODS: A cohort of 1017 breast cancer patients (inclusion 2002-2012, Sweden) were genotyped using Oncoarray by Ilumina. Patients were followed for up to 15 years. Five out of six CAV1 SNPs (rs10256914, rs959173, rs3807989, rs3815412, and rs8713) passed quality control and were used for haplotype construction. CAV1 genotypes and haplotypes in relation to clinical outcomes were assessed with Cox regression and adjusted for potential confounders (age, tumor characteristics, and adjuvant treatments). RESULTS: Only one SNP was associated with lymph node status, no other SNPs or haplotypes were associated with tumor characteristics. The CAV1 rs3815412 CC genotype (5.8% of patients) was associated with increased risk of contralateral breast cancer, adjusted hazard ratio (HRadj) 4.26 (95% CI 1.86-9.73). Moreover, the TTACA haplotype (13% of patients) conferred an increased risk for locoregional recurrence HRadj 2.24 (95% CI 1.24-4.04). No other genotypes or haplotypes were associated with clinical outcome. CONCLUSION: CAV1 polymorphisms were associated with increased risk for locoregional recurrence and contralateral breast cancer. These findings may identify patients that could derive benefit from more tailored treatment to prevent non-distant events, if confirmed.

Circulating lipids and breast cancer prognosis in the Malmö diet and cancer study.

PURPOSE: Examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). PATIENTS AND METHODS: Circulating lipid levels were measured in blood sampled upon enrollment in the female MDCS cohort (N = 17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991 and 2014. Follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or 5 years of follow-up. We estimated the incidence rates of recurrence at 5 years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). RESULTS: We enrolled 850 eligible patients. During the 5 years of follow-up, 90 invasive breast cancer recurrences were diagnosed over 3807 person-years. In multivariable analyses, high baseline levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR = 2.30 [95% CI 1.13-4.68]). However, high baseline levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR = 1.23 [95% CI 0.68-2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR = 1.34 [95% CI 0.70-2.58]) or all-cause mortality (tertile 3 vs. 1, HR = 1.12 [95% CI 0.61-2.05]). CONCLUSION: High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcomes.

Postmenopausal overweight and breast cancer risk; results from the KARMA cohort.

PURPOSE: To study the risk of incident breast cancer and subtype-specific breast cancer in relation to excess body weight in a contemporary Swedish prospective cohort study, The Karolinska Mammography Project for Risk Prediction of Breast Cancer, KARMA. METHODS: A total of 35,412 postmenopausal women attending mammography and included in the KARMA study provided baseline data on body mass index (BMI) and potential confounders. During eight years of follow-up, 822 incident invasive breast cancer cases were identified. RESULTS: Women with overweight (BMI ≥ 25-< 30 kg/m2) constituting 34% of the study cohort had an increased risk of incident breast cancer with an adjusted Hazard Ratio (HRadj) 1.19 (95% CI 1.01-1.4). A similar, however, non-significant, association was found for women with obesity (BMI ≥ 30 kg/m2) conferring 13% of the cohort, with a HRadj of 1.19 (95% CI 0.94-1.5). Overweight was associated with risk of node-negative disease (HRadj 1.29, 95% CI 1.06-1.58), whereas obesity was associated with node-positive disease (HRadj 1.64, 95% CI 1.09-2.48). Both overweight and obesity were associated with risk of estrogen receptor positive (ER+) disease (HRadj 1.20, 95% CI 1.00-1.44 and HRadj 1.33, 95% CI 1.03-1.71, respectively), and low-grade tumors (HRadj 1.25, 95% CI 1.02-1.54, and HRadj 1.40, 95% CI 1.05-1.86, respectively). Finally, obesity was associated with ER+HER2 negative disease (HRadj 1.37, 95% CI 1.05-1.78) and similarly luminal A tumors (HRadj 1.43, 95% CI 1.02-2.01). CONCLUSION: Overweight and obesity are associated with an increased risk of developing breast cancer, specifically ER+, low-grade, and for obesity, node-positive, high-risk breast cancer indicating a further need for risk communication and preventive programs.

Tumour-associated macrophages drive stromal cell-dependent collagen crosslinking and stiffening to promote breast cancer aggression.

Stromal stiffening accompanies malignancy, compromises treatment and promotes tumour aggression. Clarifying the molecular nature and the factors that regulate stromal stiffening in tumours should identify biomarkers to stratify patients for therapy and interventions to improve outcome. We profiled lysyl hydroxylase-mediated and lysyl oxidase-mediated collagen crosslinks and quantified the greatest abundance of total and complex collagen crosslinks in aggressive human breast cancer subtypes with the stiffest stroma. These tissues harbour the highest number of tumour-associated macrophages, whose therapeutic ablation in experimental models reduced metastasis, and decreased collagen crosslinks and stromal stiffening. Epithelial-targeted expression of the crosslinking enzyme, lysyl oxidase, had no impact on collagen crosslinking in PyMT mammary tumours, whereas stromal cell targeting did. Stromal cells in microdissected human tumours expressed the highest level of collagen crosslinking enzymes. Immunohistochemical analysis of biopsies from a cohort of patients with breast cancer revealed that stromal expression of lysyl hydroxylase 2, an enzyme that induces hydroxylysine aldehyde-derived collagen crosslinks and stromal stiffening, correlated significantly with disease specific mortality. The findings link tissue inflammation, stromal cell-mediated collagen crosslinking and stiffening to tumour aggression and identify lysyl hydroxylase 2 as a stromal biomarker.

The association between body mass index and pathological complete response in neoadjuvant-treated breast cancer patients.

BACKGROUND: Obesity seems to be associated with a poorer response to adjuvant chemotherapy in breast cancer (BC); however, associations in the neoadjuvant chemotherapy (NACT) setting and according to menopausal status are less studied. This study aims to investigate the association between pretreatment body mass index (BMI) and pathological complete response (pCR) following NACT in BC according to menopausal and estrogen receptor (ER) status. MATERIAL AND METHODS: The study cohort consisted of 491 patients receiving NACT in 2005-2019. Based on pre-NACT patient and tumor characteristics, the association between BMI and achieving pCR was analyzed using logistic regression models (crude and adjusted models (age, tumor size, and node status)) with stratification by menopausal and ER status. RESULTS: In the overall cohort, being overweight (BMI ≥25) compared by being normal-weight (BMI <25), increased the odds of accomplishing pCR by 15%. However, based on the 95% confidence interval (CI) the data were compatible with associations within the range of a decrease of 30% to an increase of 89%. Stratification according to menopausal status also showed no strong association: the odds ratio (OR) of accomplishing pCR in overweight premenopausal patients compared with normal-weight premenopausal patients was 1.76 (95% CI 0.88-3.55), whereas for postmenopausal patients the corresponding OR was 0.71 (95% CI 0.35-1.46). DISCUSSION: In a NACT BC cohort of 491 patients, we found no evidence of high BMI as a predictive factor of accomplishing pCR, neither in the whole cohort nor stratified by menopausal status. Given the limited precision in our results, larger studies are needed before considering BMI in clinical decision-making regarding NACT or not.

Long-term cancer risk in heterozygous familial hypercholesterolemia relatives: a 25-year cohort study.

BACKGROUND: Heterozygous familial hypercholesterolemia (HeFH) due to low-density lipoprotein receptor (LDLR) mutations predisposes patients to highly elevated levels of cholesterol, and patients are at increased risk of adverse cardiovascular events and other morbidities. Whether the LDLR mutation and high cholesterol levels affect the risk of cancer remains unknown. The purpose of the present study was to assess the long-term cancer risk in HeFH relatives. METHODS: Study participants were identified by cascade screening during 1992-1994. A comparison cohort was matched 10:1 to the relatives from the Danish general population based on birth year, gender and address. All participants were followed until a cancer diagnosis, migration, death, or end of follow-up as of December 31, 2019. The primary endpoint was any incident cancer diagnosis. RESULTS: In total, we included 221 relatives with a median age of 37 years (interquartile range: 27-53 years). A total of 117 (53%) of the relatives carried a LDLR gene mutation. The crude hazard ratio of our primary endpoint did not reveal any differences in cancer incidence in mutation-carrying relatives compared with the general population cohort (1.18; 95% CI, 0.81-1.71). Nonmutation-carrying relatives however had a lower cancer incidence than the general population (0.45: 95% CI, 0.26-0.80). Thus, the risk among mutation-carrying HeFH relatives compared with nonmutation-carrying HeFH relatives was increased (HR: 2.39; 95% CI, 1.24-4.61). CONCLUSION: In Denmark, LDLR mutation-carrying HeFH relatives did not have a different cancer risk than the general population. In contrast, nonmutation-carrying relatives had a lower risk of cancer.

Prognostic impact of tumor-specific insulin-like growth factor binding protein 7 (IGFBP7) levels in breast cancer: a prospective cohort study.

The prognostic impact of insulin-like growth factor binding protein 7 (IGFBP7) in breast cancer is unclear. Host factors, including lifestyle, anthropometry and metabolic profile, might influence tumor-specific IGFBP7. This study aimed to investigate whether IGFBP7 levels and messenger ribonucleic acid (mRNA) expression are associated with the patient and tumor characteristics and prognosis in breast cancer. Patients with primary breast cancer in Lund, Sweden, were included preoperatively in the study between 2002 and 2012 (n = 1018). Tumor-specific IGFBP7 protein levels were evaluated with immunohistochemistry using tissue microarrays in tumors from 878 patients. IGFBP7 mRNA expression and its corresponding clinical data were obtained from The Cancer Genome Atlas and analyzed for 809 patients. Tumor-specific IGFBP7 protein levels were categorized based on Histo 300 scores into IGFBP7low (6.2%), IGFBP7intermediate (75.7%) and IGFBP7high (18.1%). Both low IGFBP7 protein levels and mRNA expression were associated with less aggressive tumor characteristics. Overall, IGFBP7low conferred low recurrence risk. The prognostic impact of IGFBP7high varied according to any alcohol consumption and tamoxifen treatment. IGFBP7high was associated with low recurrence risk in alcohol consumers but high recurrence risk in alcohol abstainers (Pinteraction= 0.039). Moreover, the combination of IGFBP7high and estrogen receptor-positive tumors was associated with low recurrence risk only in tamoxifen-treated patients (Pinteraction= 0.029). To conclude, IGFBP7low might be a good, independent prognosticator in breast cancer. The prognostic impact of IGFBP7high depends on host factors and treatment. IGFBP7 merits further investigation to confirm whether it could be a suitable biomarker for treatment selection.

Low thyroid hormone receptor alpha-2 (THRα-2) tumor expression is associated with unfavorable tumor characteristics and high breast cancer mortality.

BACKGROUND: The active thyroid hormone triiodothyronine (T3) has been found to have an estrogen-like effect on breast cancer cells. Thyroid hormone receptor alpha-2 (THRα-2) acts as an antagonist for triiodothyronine (T3) signaling, and a low expression has been associated with unfavorable tumor characteristics and a higher mortality in breast cancer. However, the evidence are not conclusive. The present study evaluates tumor-specific THRα-2 expression in invasive breast cancers and its association with tumor characteristics and long-term mortality in a large population. METHOD: The Malmö Diet and Cancer Study (MDCS), a population-based cohort in Sweden that included 17,035 women from 1991 to 1996, was used. Women diagnosed with breast cancer during 1991-2010 were eligible for inclusion. A tissue micro array was constructed from stored tumor material and stained for THRα-2 using immunohistochemistry. Tumors from 654 patients were scored regarding the intensity and the fraction of cells stained, then dichotomized into low or high expression. Date and cause of death were collected up until 2018-12-31. Tumor- and patient characteristics were available from the MDCS. Missing data was imputed using chained equations. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for low vs high expression of THRα-2 related to specific tumor factors. Mortality was evaluated with Kaplan-Meier curves and Cox regression, rendering hazard ratios (HRs). Analyses were also stratified for estrogen receptor (ER) status. RESULTS: We found strong evidence of an association between low THRα-2 and unfavorable tumor characteristics, including estrogen receptor negativity: OR 4.04 (95% CI 2.28-7.15) and tumor size > 20-50 mm: OR 2.20 (95% CI 1.39-3.49). We found evidence of increased breast cancer-specific mortality for women with low THRα-2, HR 1.38 (95% CI 0.96-1.99), which remained after adjusting for age at diagnosis, HR 1.48 (95% CI 1.03-2.14), but not after adjusting for relevant prognostic factors, HR 0.98 (95% CI 0.66-1.45). THRα-2 expression in ER-negative tumors had an inverse correlation with overall mortality, HR 0.27 (95% CI 0.11-0.65). CONCLUSION: Low tumor-specific THRα-2 expression was in this study associated with prognostically unfavorable tumor characteristics and a higher mortality in breast cancer, but not independent from other prognostic factors.

Distinct mechanisms of resistance to fulvestrant treatment dictate level of ER independence and selective response to CDK inhibitors in metastatic breast cancer.

BACKGROUND: Resistance to endocrine treatment in metastatic breast cancer is a major clinical challenge. Clinical tools to predict both drug resistance and possible treatment combination approaches to overcome it are lacking. This unmet need is mainly due to the heterogeneity underlying both the mechanisms involved in resistance development and breast cancer itself. METHODS: To study the complexity of the mechanisms involved in the resistance to the selective estrogen receptor degrader (SERD) fulvestrant, we performed comprehensive biomarker analyses using several in vitro models that recapitulate the heterogeneity of developed resistance. We further corroborated our findings in tissue samples from patients treated with fulvestrant. RESULTS: We found that different in vitro models of fulvestrant resistance show variable stability in their phenotypes, which corresponded with distinct genomic alterations. Notably, the studied models presented adaptation at different cell cycle nodes to facilitate progression through the cell cycle and responded differently to CDK inhibitors. Cyclin E2 overexpression was identified as a biomarker of a persistent fulvestrant-resistant phenotype. Comparison of pre- and post-treatment paired tumor biopsies from patients treated with fulvestrant revealed an upregulation of cyclin E2 upon development of resistance. Moreover, overexpression of this cyclin was found to be a prognostic factor determining resistance to fulvestrant and shorter progression-free survival. CONCLUSIONS: These data highlight the complexity of estrogen receptor positive breast cancer and suggest that the development of diverse resistance mechanisms dictate levels of ER independence and potentially cross-resistance to CDK inhibitors.

Serum zinc and dietary intake of zinc in relation to risk of different breast cancer subgroups and serum levels as a marker of intake: a prospective nested case-control study.

PURPOSE: Zinc has been suggested to be protective against breast cancer, but the evidence remains inconclusive. One reason for inconsistent findings in previous studies may be that zinc only influences the risk of developing certain subtypes of breast cancer. Our study is the first study assessing zinc levels in relation to the risk of different breast cancer subgroups, defined by their tumor characteristics. In addition, we analyze serum zinc as a marker of dietary intake. METHODS: The Malmö Diet and Cancer Study is a population-based cohort study that took place 1991-1996 in Malmö, Sweden. Until end of follow-up, 31 December 2013, 1186 incident cases were identified and matched to an equal number of controls. Odds ratios (ORs) for breast cancer, and having a certain tumor characteristic, were estimated in quartiles of baseline serum zinc and zinc intake and adjusted for potential confounders. RESULTS: No associations were found between zinc, measured in serum or diet pre-diagnostically, and breast cancer risk. The adjusted OR for breast cancer in serum zinc Q4 compared to Q1 was 1.09 (0.85-1.41) and in zinc intake Q4 versus Q1 was 0.97 (0.77-1.23). Moreover, there were no clear associations between zinc and any breast cancer characteristics. The kappa value, 0.025 (P = 0.022), showed poor agreement between serum zinc and zinc intake. CONCLUSION: Our findings indicate that there is no clear association between zinc and overall breast cancer risk or risk of different breast cancer subgroups. Finally, our results suggest that serum zinc is a poor marker of zinc intake.

Predicting pathological axillary lymph node status with ultrasound following neoadjuvant therapy for breast cancer.

PURPOSE: High-performing imaging and predictive markers are warranted to minimize surgical overtreatment of the axilla in breast cancer (BC) patients receiving neoadjuvant chemotherapy (NACT). Here we have investigated whether axillary ultrasound (AUS) could identify axillary lymph node (ALN) metastasis (ALNM) pre-NACT and post-NACT for BC. The association of tumor, AUS features and mammographic density (MD) with axillary-pathological complete response (axillary-pCR) post-NACT was also assessed. METHODS: The NeoDense-study cohort (N = 202, NACT during 2014-2019), constituted a pre-NACT cohort, whereas patients whom had a cytology verified ALNM pre-NACT and an axillary dissection performed (N = 114) defined a post-NACT cohort. AUS characteristics were prospectively collected pre- and post-NACT. The diagnostic accuracy of AUS was evaluated and stratified by histological subtype and body mass index (BMI). Predictors of axillary-pCR were analyzed, including MD, using simple and multivariable logistic regression models. RESULTS: AUS demonstrated superior performance for prediction of ALNM pre-NACT in comparison to post-NACT, as reflected by the positive predictive value (PPV) 0.94 (95% CI 0.89-0.97) and PPV 0.76 (95% CI 0.62-0.87), respectively. We found no difference in AUS performance according to neither BMI nor histological subtype. Independent predictors of axillary-pCR were: premenopausal status, ER-negativity, HER2-overexpression, and high MD. CONCLUSION: Baseline AUS could, to a large extent, identify ALNM; however, post-NACT, AUS was insufficient to determine remaining ALNM. Thus, our results support the surgical staging of the axilla post-NACT. Baseline tumor biomarkers and patient characteristics were predictive of axillary-pCR. Larger, multicenter studies are needed to evaluate the performance of AUS post-NACT.

Dietary intake of trans fatty acids and breast cancer risk in 9 European countries.

BACKGROUND: Trans fatty acids (TFAs) have been hypothesised to influence breast cancer risk. However, relatively few prospective studies have examined this relationship, and well-powered analyses according to hormone receptor-defined molecular subtypes, menopausal status, and body size have rarely been conducted. METHODS: In the European Prospective Investigation into Cancer and Nutrition (EPIC), we investigated the associations between dietary intakes of TFAs (industrial trans fatty acids [ITFAs] and ruminant trans fatty acids [RTFAs]) and breast cancer risk among 318,607 women. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusted for other breast cancer risk factors. RESULTS: After a median follow-up of 8.1 years, 13,241 breast cancer cases occurred. In the multivariable-adjusted model, higher total ITFA intake was associated with elevated breast cancer risk (HR for highest vs lowest quintile, 1.14, 95% CI 1.06-1.23; P trend = 0.001). A similar positive association was found between intake of elaidic acid, the predominant ITFA, and breast cancer risk (HR for highest vs lowest quintile, 1.14, 95% CI 1.06-1.23; P trend = 0.001). Intake of total RTFAs was also associated with higher breast cancer risk (HR for highest vs lowest quintile, 1.09, 95% CI 1.01-1.17; P trend = 0.015). For individual RTFAs, we found positive associations with breast cancer risk for dietary intakes of two strongly correlated fatty acids (Spearman correlation r = 0.77), conjugated linoleic acid (HR for highest vs lowest quintile, 1.11, 95% CI 1.03-1.20; P trend = 0.001) and palmitelaidic acid (HR for highest vs lowest quintile, 1.08, 95% CI 1.01-1.16; P trend = 0.028). Similar associations were found for total ITFAs and RTFAs with breast cancer risk according to menopausal status, body mass index, and breast cancer subtypes. CONCLUSIONS: These results support the hypothesis that higher dietary intakes of ITFAs, in particular elaidic acid, are associated with elevated breast cancer risk. Due to the high correlation between conjugated linoleic acid and palmitelaidic acid, we were unable to disentangle the positive associations found for these fatty acids with breast cancer risk. Further mechanistic studies are needed to identify biological pathways that may underlie these associations.

Mammographic density as an image-based biomarker of therapy response in neoadjuvant-treated breast cancer patients.

PURPOSE: Personalized cancer treatment requires predictive biomarkers, including image-based biomarkers. Breast cancer (BC) patients receiving neoadjuvant chemotherapy (NACT) are in a clinically vulnerable situation with the tumor present. This study investigated whether mammographic density (MD), assessed pre-NACT, is predictive of pathological complete response (pCR). METHODS: A total of 495 BC patients receiving NACT in Sweden 2005-2019 were included, merged from two different cohorts. Cohort 1 was retrospectively collected (n = 295) and cohort 2 was prospectively collected (n = 200). Mammograms were scored for MD pre-NACT according to the Breast Imaging-Reporting and Data System (BI-RADS), 5th Edition. The association between MD and accomplishing pCR post-NACT was analyzed using logistic regression models-for the whole cohort, stratified by menopausal status, and in different St. Gallen surrogate subtypes. RESULTS: In comparison to patients with low MD (BI-RADS a), the multivariable-adjusted odds ratio (OR) of accomplishing pCR following NACT was on a descending scale: 0.62 (95% confidence interval (CI) 0.24-1.57), 0.38 (95% CI 0.14-1.02), and 0.32 (95% CI 0.09-1.08) for BI-RADS b, c, and d, respectively. For premenopausal patients selectively, the corresponding point estimates were lower, although wider CIs: 0.31 (95% CI 0.06-1.62), 0.24 (95% CI 0.04-1.27), and 0.13 (95% CI 0.02-0.88). Subgroup analyses based on BC subtypes resulted in imprecise estimates, i.e., wide CIs. CONCLUSIONS: It seemed as though patients with higher MD at baseline were less likely to reach pCR after NACT-a finding more pronounced in premenopausal women. Larger multicenter studies are needed to enable analyses and interpretation for different BC subtypes.