A Survey among Breast Cancer Specialists on the Low Uptake of Therapeutic Prevention with Tamoxifen or Raloxifene

Breast Articles From 2023: Informing Practice Across the Continuum of Care

With new investigations and clinical trials in breast oncology reported every year, it is critical that surgeons be aware of advances and insights into the evolving care paradigms and treatments available to their patients. This article highlights five publications found to be particularly impactful this past year. These articles report on efforts to select the minimal effective dose of tamoxifen for prevention, to challenge the existing age-based screening guidelines as they relate to race and ethnicity, to refine axillary management treatment standards, to optimize systemic therapy in multidisciplinary care settings, and to reduce the burden of breast cancer-related lymphedema after treatment. Taken together, these efforts have an impact on all facets of the continuum of care from prevention and screening through treatment and survivorship.

Spatial heterogeneity of peri-tumoural lipid composition in postmenopausal patients with oestrogen receptor positive breast cancer

Deregulation of lipid composition in adipose tissue adjacent to breast tumour is observed in ex vivo and animal models. Novel non-invasive magnetic resonance imaging (MRI) allows rapid lipid mapping of the human whole breast. We set out to elucidate the spatial heterogeneity of peri-tumoural lipid composition in postmenopausal patients with oestrogen receptor positive (ER +) breast cancer. Thirteen participants (mean age, 62 ± [SD] 6 years) with ER + breast cancer and 13 age-matched postmenopausal healthy controls were scanned on MRI. The number of double bonds in triglycerides was computed from MRI images to derive lipid composition maps of monounsaturated, polyunsaturated, and saturated fatty acids (MUFA, PUFA, SFA). The spatial heterogeneity measures (mean, median, skewness, entropy and kurtosis) of lipid composition in the peri-tumoural region and the whole breast of participants and in the whole breast of controls were computed. The Ki-67 proliferative activity marker and CD163 antibody on tumour-associated macrophages were assessed histologically. Mann Whitney U or Wilcoxon tests and Spearman's coefficients were used to assess group differences and correlations, respectively. For comparison against the whole breast in participants, peri-tumoural MUFA had a lower mean (median (IQR), 0.40 (0.02), p < .001), lower median (0.42 (0.02), p < .001), a negative skewness with lower magnitude (- 1.65 (0.77), p = .001), higher entropy (4.35 (0.64), p = .007) and lower kurtosis (5.13 (3.99), p = .001). Peri-tumoural PUFA had a lower mean (p < .001), lower median (p < .001), a positive skewness with higher magnitude (p = .005) and lower entropy (p = .002). Peri-tumoural SFA had a higher mean (p < .001), higher median (p < .001), a positive skewness with lower magnitude (p < .001) and lower entropy (p = .012). For comparison against the whole breast in controls, peri-tumoural MUFA had a negative skewness with lower magnitude (p = .01) and lower kurtosis (p = .009), however there was no difference in PUFA or SFA. CD163 moderately correlated with peri-tumoural MUFA skewness (rs = - .64), PUFA entropy (rs = .63) and SFA skewness (rs = .59). There was a lower MUFA and PUFA while a higher SFA, and a higher heterogeneity of MUFA while a lower heterogeneity of PUFA and SFA, in the peri-tumoural region in comparison with the whole breast tissue. The degree of lipid deregulation was associated with inflammation as indicated by CD163 antibody on macrophages, serving as potential marker for early diagnosis and response to therapy.

Efficacy of Alternative Dose Regimens of Exemestane in Postmenopausal Women With Stage 0 to II Estrogen Receptor-Positive Breast Cancer: A Randomized Clinical Trial

Importance

Successful therapeutic cancer prevention requires definition of the minimal effective dose. Aromatase inhibitors decrease breast cancer incidence in high-risk women, but use in prevention and compliance in adjuvant settings are hampered by adverse events.

Objective

To compare the noninferiority percentage change of estradiol in postmenopausal women with estrogen receptor-positive breast cancer given exemestane, 25 mg, 3 times weekly or once weekly vs a standard daily dose with a noninferiority margin of -6%.

Design, Setting, and Participants

This multicenter, presurgical, double-blind phase 2b randomized clinical trial evaluated 2 alternative dosing schedules of exemestane. Postmenopausal women with estrogen receptor-positive breast cancer who were candidates for breast surgery were screened from February 1, 2017, to August 31, 2019. Blood samples were collected at baseline and final visit; tissue biomarker changes were assessed from diagnostic biopsy and surgical specimen. Biomarkers were measured in different laboratories between April 2020 and December 2021.

Interventions

Exemestane, 25 mg, once daily, 3 times weekly, or once weekly for 4 to 6 weeks before surgery.

Main Outcomes and Measures

Serum estradiol concentrations were measured by solid-phase extraction followed by liquid chromatography-tandem mass spectrometry detection. Toxic effects were evaluated using the National Cancer Institute terminology criteria, and Ki-67 was assessed by immunohistochemistry.

Results

A total of 180 women were randomized into 1 of the 3 arms; median (IQR) age was 66 (60-71) years, 63 (60-69) years, and 65 (61-70) years in the once-daily, 3-times-weekly, and once-weekly arms, respectively. In the intention-to-treat population (n = 171), the least square mean percentage change of serum estradiol was -89%, -85%, and -60% for exemestane once daily (n = 55), 3 times weekly (n = 56), and once weekly (n = 60), respectively. The difference in estradiol percentage change between the once-daily and 3-times-weekly arms was -3.6% (P for noninferiority = .37), whereas in compliant participants (n = 153), it was 2.0% (97.5% lower confidence limit, -5.6%; P for noninferiority = .02). Among secondary end points, Ki-67 and progesterone receptor were reduced in all arms, with median absolute percentage changes of -7.5%, -5.0%, and -4.0% for Ki-67 in the once-daily, 3-times-weekly, and once-weekly arms, respectively (once daily vs 3 times weekly, P = .31; once daily vs once weekly, P = .06), and -17.0%, -9.0%, and -7.0% for progesterone receptor, respectively. Sex hormone-binding globulin and high-density lipoprotein cholesterol had a better profile among participants in the 3-times-weekly arm compared with once-daily arm. Adverse events were similar in all arms.

Conclusions and Relevance

In this randomized clinical trial, exemestane, 25 mg, given 3 times weekly in compliant patients was noninferior to the once-daily dosage in decreasing serum estradiol. This new schedule should be further studied in prevention studies and in women who do not tolerate the daily dose in the adjuvant setting.

Trial Registration

ClinicalTrials.gov Identifier: NCT02598557; EudraCT: 2015-005063-16.

Reassessing the Benefits and Harms of Risk-Reducing Medication Considering the Persistent Risk of Breast Cancer Mortality in Estrogen Receptor-Positive Breast Cancer

PURPOSE

Recent studies, including a meta-analysis of 88 trials, have shown higher than expected rates of recurrence and death in hormone receptor-positive breast cancer. These new findings suggest a need to re-evaluate the use of risk-reducing medication to avoid invasive breast cancer and breast cancer death in high-risk women.

METHODS

We adapted an established Cancer Intervention and Surveillance Modeling Network model to evaluate the lifetime benefits and harms of risk-reducing medication in women with a ≥ 3% 5-year risk of developing breast cancer according to the Breast Cancer Surveillance Consortium risk calculator. Model input parameters were derived from meta-analyses, clinical trials, and large observational data. We evaluated the effects of 5 years of risk-reducing medication (tamoxifen/aromatase inhibitors) with annual screening mammography ± magnetic resonance imaging (MRI) compared with no screening, MRI, or risk-reducing medication. The modeled outcomes included invasive breast cancer, breast cancer death, side effects, false positives, and overdiagnosis. We conducted subgroup analyses for individual risk factors such as age, family history, and prior biopsy.

RESULTS

Risk-reducing tamoxifen with annual screening (± MRI) decreased the risk of invasive breast cancer by 40% and breast cancer death by 57%, compared with no tamoxifen or screening. This is equivalent to an absolute reduction of 95 invasive breast cancers, and 42 breast cancer deaths per 1,000 high-risk women. However, these drugs are associated with side effects. For example, tamoxifen could increase the number of endometrial cancers up to 11 per 1,000 high-risk women. Benefits and harms varied by individual characteristics.

CONCLUSION

The addition of risk-reducing medication to screening could further decrease the risk of breast cancer death. Clinical guidelines for high-risk women should consider integrating shared decision making for risk-reducing medication and screening on the basis of individual risk factors.

Patient- versus physician-reported outcomes in a low-dose tamoxifen trial in noninvasive breast cancer

BACKGROUND

We recently conducted a de-escalation trial of low-dose tamoxifen 5 mg/day ("babytam", BT) or placebo given for 3 years in 500 women with noninvasive breast cancer. Women on babytam had a 52% reduction of recurrence (invasive breast cancer or DCIS) after 5 years. Since menopausal symptoms are major reasons for treatment withdrawal during tamoxifen preventive therapy, we compared and analyzed the patient-reported outcomes (PROs) with the physician-reported adverse events and studied their association with recurrence.

METHODS

Menopausal symptoms recorded by physicians using the Common Terminology Criteria (CTCAEs) were compared with a patient self-reported validated questionnaire reviewed by a research nurse at baseline and every 6 months up to 36 months. Hot flashes (HF), the main outcome measure, were detected through a self-report 7-day diary for frequency and intensity. Treatment adherence and efficacy were assessed by the Kaplan-Meier curves and the Cox model.

RESULTS

The number of HF events at 12, 24, and 36 months for PROs versus CTCAEs was 246 versus 12, 238 versus 8, and 210 versus 4, respectively. The majority of events were grade 1. There was no difference in PROs between babytam and placebo except for HF daily frequency, which increased by 1.5 events (95% CI, 1.1-1.8) on placebo to 2.1 on babytam (95% CI, 1.7-2.5, p = 0.05). The presence of HF at baseline was a favorable prognostic factor for recurrence and a predictive factor for response to babytam. Adherence was similar between babytam and placebo.

CONCLUSIONS

The use of PROs is effective for identifying frequent mild grade menopausal symptoms which are underestimated by physicians but important prognostic and predictive factors. Research nurse can use these results as a tool to reassure patients about symptoms, improve adherence to treatment, and limit dropouts.

Upgrade rates and outcomes of screen-detected atypical intraductal epithelial proliferation (AIDEP) diagnosed on core needle biopsy

INTRODUCTION

Atypical intraductal epithelial proliferation (AIDEP) is a breast lesion categorised as "indeterminate" if identified on core needle biopsy (CNB). The rate at which these lesions are upgraded following diagnostic excision varies in the literature. Women diagnosed with AIDEP are thought to be at increased risk of breast cancer. Our aim was to identify the rate of upgrade to invasive or in situ carcinoma in a group of patients diagnosed with AIDEP on screening mammography and to quantify their risk of subsequent breast cancer.

METHODS

We conducted a retrospective review of a prospectively maintained database containing all patients diagnosed with AIDEP on CNB between 2005 and 2012 in an Irish breast screening centre. Basic demographic data was collected along with details of the original CNB result, rate of upgrade to carcinoma and details of any subsequent cancer diagnoses.

RESULTS

In total 113 patients were diagnosed with AIDEP on CNB during the study period. The upgrade rate on diagnostic excision was 28.3% (n = 32). 6.2% (n = 7) were upgraded to invasive cancer and 22.1% (n = 25) to DCIS. 81 patients were not upgraded on diagnostic excision and were offered 5 years of annual mammographic surveillance. 9.88% (8/81) of these patients went on to receive a subsequent diagnosis of malignancy. The mean time to diagnosis of these subsequent cancers was 65.41 months (range 20.18-145.21).

CONCLUSION

Our data showing an upgrade rate of 28% to carcinoma reflects recently published data and we believe it supports the continued practice of excising AIDEP to exclude co-existing carcinoma.

Understanding low chemoprevention uptake by women at high risk of breast cancer: findings from a qualitative inductive study of women's risk-reduction experiences

BACKGROUND

Chemoprevention is one of several methods that have been developed to help high-risk women reduce their risk of breast cancer. Reasons for the low uptake of chemoprevention are poorly understood. This paper seeks a deeper understanding of this phenomenon by drawing on women's own narratives about their awareness of chemoprevention and their risk-related experiences.

METHODS

This research is based on a parent project that included fifty in-depth, semi-structured interviews with a purposive sample of African American and White women at elevated risk of breast cancer. This specific study draws on the forty-seven interviews conducted with women at high or severe risk of breast cancer, all of whom are eligible to use chemoprevention for breast cancer risk-reduction. Interviews were analyzed using grounded theory methods.

RESULTS

Forty-five percent of participants, and only 21% of African American participants, were aware of chemoprevention options. Women who had seen specialists were more likely to be aware, particularly if they had ongoing specialist access. Aware and unaware women relied on different types of sources for prevention-related information. Those whose main source of information was a healthcare provider were more likely to know about chemoprevention. Aware women used more nuanced information gathering strategies and worried more about cancer. Women simultaneously considered all risk-reduction options they knew about. Those who knew about chemoprevention but were reluctant to use it felt this way for multiple reasons, having to do with potential side effects, perceived extreme-ness of the intervention, similarity to chemotherapy, unknown information about chemoprevention, and reluctance to take medications in general.

CONCLUSIONS

Lack of chemoprevention awareness is a critical gap in women's ability to make health-protective choices. Future research in this field must consider complexities in both women's perspectives on chemoprevention and the reasons they are reluctant to use it.

Effect Modifiers of Low-Dose Tamoxifen in a Randomized Trial in Breast Noninvasive Disease

PURPOSE

Low-dose tamoxifen halved recurrence after surgery in a phase III trial in breast noninvasive disease without increasing adverse events. We explored the effect of low-dose tamoxifen in clinically relevant subgroups, including menopausal status, estradiol levels, smoking, body mass index, and proliferation of baseline lesion.

PATIENTS AND METHODS

Incidence of invasive breast cancer or ductal carcinoma in situ was the primary endpoint. HRs and interaction terms were estimated using Cox models.

RESULTS

A favorable HR and 95% confidence interval (CI) could be demonstrated for postmenopausal status (HR = 0.30; 95% CI, 0.11-0.82 vs. HR = 0.73; 95% CI, 0.30-1.76 in premenopausal women; P _interaction = 0.13), women with estradiol less than 15.8 pg/mL, presence of menopausal symptoms at baseline, and never smoking (P _interaction = 0.07), although the interaction P value was >0.05 for all characteristics. Efficacy was similar in all body mass index categories. Tumors with Ki-67 above the median level of 10% had a greater benefit (HR = 0.27; 95% CI, 0.09-0.81) than those with Ki-67 ≤10% (HR = 1.58; 95% CI, 0.45-5.60; P _interaction = 0.04).

CONCLUSIONS

The efficacy of low-dose tamoxifen seems to be greater in postmenopausal women and in women with lower estradiol levels. Benefits appear to be larger also in women with menopausal symptoms, never smokers, and tumors with Ki-67 >10%. Our results by menopausal status provide important insight into low-dose tamoxifen personalized treatment, although caution is necessary given their exploratory nature. Observation of an improved response in tumors with Ki-67 >10% is consistent but the use of the marker in this setting is investigational.See related commentary by Fabian, p. 3510.

Breast Cancer Chemoprevention: Use and Views of Australian Women and Their Clinicians

Guidelines endorse the use of chemoprevention for breast cancer risk reduction. This study examined the barriers and facilitators to chemoprevention use for Australian women at increased risk of breast cancer, and their clinicians. Surveys, based on the Theoretical Domains Framework, were mailed to 1,113 women at ≥16% lifetime risk of breast cancer who were enrolled in the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer cohort study (kConFab), and their 524 treating clinicians. Seven hundred twenty-five women (65%) and 221 (42%) clinicians responded. Only 10 (1.4%) kConFab women had ever taken chemoprevention. Three hundred seventy-eight (52%) kConFab women, two (3%) breast surgeons, and 51 (35%) family physicians were not aware of chemoprevention. For women, the strongest barriers to chemoprevention were side effects (31%) and inadequate information (23%), which operate in the Theoretical Domains Framework domains of "beliefs about consequences" and "knowledge," respectively. Strongest facilitators related to tamoxifen's long-term efficacy (35%, "knowledge," "beliefs about consequences," and "goals" domains), staying healthy for family (13%, "social role" and "goals" domains), and abnormal breast biopsy (13%, "environmental context" domain). The strongest barrier for family physicians was insufficient knowledge (45%, "knowledge" domain) and for breast surgeons was medication side effects (40%, "beliefs about consequences" domain). The strongest facilitators for both clinician groups related to clear guidelines, strong family history, and better tools to select patients ("environmental context and resources" domain). Clinician knowledge and resources, and beliefs about the side-effect consequences of chemoprevention, are key domains that could be targeted to potentially enhance uptake. PREVENTION RELEVANCE: Despite its efficacy in reducing breast cancer incidence, chemoprevention is underutilised. This survey study of Australian women and their clinicians used behavioural change theory to identify modifiable barriers to chemoprevention uptake, and to suggest interventions such as policy change, educational resources and public campaigns, that may increase awareness and use.See related Spotlight by Vogel, p. 1.

Specialist recommendation for chemoprevention medications in patients at familial risk of breast cancer: a cross-sectional survey in England

In England, the National Institute for Health and Care Excellence guideline for familial breast cancer recommends chemoprevention for women at high and moderate familial risk of breast cancer. However, prescribing of chemoprevention has not improved since the introduction of the guideline in 2013. The study aims to identify the current practice, in England, of familial cancer specialists offering chemoprevention and recommending prescribing in primary care. This was an anonymized national cross-sectional survey of familial breast cancer risk services in England. Lead clinicians were sent an online survey link. The survey questions included whether chemoprevention was offered/considered for high- and moderate-risk women, when chemoprevention prescribing and recommendation to primary care started, medications prescribed, age groups considered for chemoprevention, and existence of a shared prescribing protocol with primary care. The survey was sent to 115 hospital services; responses from 50 services (43%) were included in the analysis. Of the 40 services offering chemoprevention for high-risk women, 15 (38%) did not prescribe but 31 (78%) recommended prescribing to primary care. Of the 31 services considering chemoprevention for moderate risk, eight (26%) did not prescribe with 26 (84%) recommended prescribing to primary care. Only three services reported having a shared protocol with primary care. Within 3 years of the guidelines, many services recognized the role of chemoprevention for both high and moderate risk with a key role for primary care to initiate prescribing. However, there is still room for improvement.

Key steps for effective breast cancer prevention

Despite decades of laboratory, epidemiological and clinical research, breast cancer incidence continues to rise. Breast cancer remains the leading cancer-related cause of disease burden for women, affecting one in 20 globally and as many as one in eight in high-income countries. Reducing breast cancer incidence will likely require both a population-based approach of reducing exposure to modifiable risk factors and a precision-prevention approach of identifying women at increased risk and targeting them for specific interventions, such as risk-reducing medication. We already have the capacity to estimate an individual woman's breast cancer risk using validated risk assessment models, and the accuracy of these models is likely to continue to improve over time, particularly with inclusion of newer risk factors, such as polygenic risk and mammographic density. Evidence-based risk-reducing medications are cheap, widely available and recommended by professional health bodies; however, widespread implementation of these has proven challenging. The barriers to uptake of, and adherence to, current medications will need to be considered as we deepen our understanding of breast cancer initiation and begin developing and testing novel preventives.

Estimating the magnitude of clinical benefit of systemic therapy in patients with DCIS or pre-invasive disease of the breast

The challenge of effective management of ductal carcinoma in situ (DCIS) and other pre-malignant disorders of the breast is to select patients who will not progress to invasive carcinoma from those at the highest risk who require radiotherapy and/or endocrine therapy to minimize the risk of a subsequent invasive recurrence. Although IBIS-II and NSABP-B35 DCIS phase III trials proved that tamoxifen 20 mg/day and anastrozole reduce the risk of ipsilateral and contralateral events, the toxicities of both drugs have hampered the drug uptake by high-risk women. We recently reported results of a 3-year placebo-controlled trial of low-dose (5 mg/d) tamoxifen in 500 women with intraepithelial neoplasia (70% DCIS). At a median follow-up of 5 years, women randomly assigned to low-dose tamoxifen had half the number of subsequent diagnoses of DCIS or invasive cancer compared with those randomly assigned to placebo but no increase in thromboembolic events or endometrial cancers. The 5-year number needed to treat was 22 (95% CI, 20-27). Our attention is now focused on prognostic and predictive markers to identify patients who can derive the greatest benefits from low dose tamoxifen, such as for instance the expression of 23 genes involved in cell cycle progression (CCP). In conclusion, we endorse an active treatment of DCIS as the standard of care.

Accuracy of Risk Estimates from the iPrevent Breast Cancer Risk Assessment and Management Tool

BACKGROUND

iPrevent is an online breast cancer (BC) risk management decision support tool. It uses an internal switching algorithm, based on a woman's risk factor data, to estimate her absolute BC risk using either the International Breast Cancer Intervention Study (IBIS) version 7.02, or Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm version 3 models, and then provides tailored risk management information. This study assessed the accuracy of the 10-year risk estimates using prospective data.

METHODS

iPrevent-assigned 10-year invasive BC risk was calculated for 15 732 women aged 20-70 years and without BC at recruitment to the Prospective Family Study Cohort. Calibration, the ratio of the expected (E) number of BCs to the observed (O) number and discriminatory accuracy were assessed.

RESULTS

During the 10 years of follow-up, 619 women (3.9%) developed BC compared with 702 expected (E/O = 1.13; 95% confidence interval [CI] =1.05 to 1.23). For women younger than 50 years, 50 years and older, and BRCA1/2-mutation carriers and noncarriers, E/O was 1.04 (95% CI = 0.93 to 1.16), 1.24 (95% CI = 1.11 to 1.39), 1.13 (95% CI = 0.96 to 1.34), and 1.13 (95% CI = 1.04 to 1.24), respectively. The C-statistic was 0.70 (95% CI = 0.68 to 0.73) overall and 0.74 (95% CI = 0.71 to 0.77), 0.63 (95% CI = 0.59 to 0.66), 0.59 (95% CI = 0.53 to 0.64), and 0.65 (95% CI = 0.63 to 0.68), respectively, for the subgroups above. Applying the newer IBIS version 8.0b in the iPrevent switching algorithm improved calibration overall (E/O = 1.06, 95% CI = 0.98 to 1.15) and in all subgroups, without changing discriminatory accuracy.

CONCLUSIONS

For 10-year BC risk, iPrevent had good discriminatory accuracy overall and was well calibrated for women aged younger than 50 years. Calibration may be improved in the future by incorporating IBIS version 8.0b.

Heterogeneous risk profiles among B3 breast lesions of uncertain malignant potential

Background:

Most cases of breast lesions of uncertain malignant potential (B3) undergo surgical intervention. We aimed to analyze the outcome of B3 lesion subtypes in a large series of screen-detected cases.

Methods:

We screened 2,986 core needle biopsies to classify B3 lesions. Positive predictive values (PPVs) for malignancy were calculated for a comprehensive risk characterization according to clinicopathologic and morphologic variables.

Results:

B3 lesions comprised 35% atypical ductal hyperplasia (PPV = 20%), 16.7% flat epithelial atypia (PPV = 12%), 22.7% lobular neoplasia (PPV = 16.2%), 9% papillary lesion (PPV = 18.5%), 8.6% phyllodes tumor (PPV = 3.8%), and 8% radial scars (PPV = 4.1%) based on histopathologic diagnosis. Upgrade rates were 15.9% for calcifications, 13.7% for mass lesions, and 16.7% for architectural deformities, with 8.3% of malignant lesions classified as ductal carcinoma in situ and 6.7% as invasive cancers (PPV = 15%).

Conclusion:

B3 lesions entail a heterogeneous risk of malignancy, and careful radiologic–pathologic correlation is required for optimal treatment.

Regular use of aspirin and other non-steroidal anti-inflammatory drugs and breast cancer risk for women at familial or genetic risk: a cohort study

Background

The use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with reduced breast cancer risk, but it is not known if this association extends to women at familial or genetic risk. We examined the association between regular NSAID use and breast cancer risk using a large cohort of women selected for breast cancer family history, including 1054 BRCA1 or BRCA2 mutation carriers.

Methods

We analyzed a prospective cohort (N = 5606) and a larger combined, retrospective and prospective, cohort (N = 8233) of women who were aged 18 to 79 years, enrolled before June 30, 2011, with follow-up questionnaire data on medication history. The prospective cohort was further restricted to women without breast cancer when medication history was asked by questionnaire. Women were recruited from seven study centers in the United States, Canada, and Australia. Associations were estimated using multivariable Cox proportional hazards regression models adjusted for demographics, lifestyle factors, family history, and other medication use. Women were classified as regular or non-regular users of aspirin, COX-2 inhibitors, ibuprofen and other NSAIDs, and acetaminophen (control) based on self-report at follow-up of ever using the medication for at least twice a week for ≥1 month prior to breast cancer diagnosis. The main outcome was incident invasive breast cancer, based on self- or relative-report (81% confirmed pathologically).

Results

From fully adjusted analyses, regular aspirin use was associated with a 39% and 37% reduced risk of breast cancer in the prospective (HR = 0.61; 95% CI = 0.33–1.14) and combined cohorts (HR = 0.63; 95% CI = 0.57–0.71), respectively. Regular use of COX-2 inhibitors was associated with a 61% and 71% reduced risk of breast cancer (prospective HR = 0.39; 95% CI = 0.15–0.97; combined HR = 0.29; 95% CI = 0.23–0.38). Other NSAIDs and acetaminophen were not associated with breast cancer risk in either cohort. Associations were not modified by familial risk, and consistent patterns were found by BRCA1 and BRCA2 carrier status, estrogen receptor status, and attained age.

Conclusion

Regular use of aspirin and COX-2 inhibitors might reduce breast cancer risk for women at familial or genetic risk.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1135-y) contains supplementary material, which is available to authorized users.

Randomized Placebo Controlled Trial of Low-Dose Tamoxifen to Prevent Local and Contralateral Recurrence in Breast Intraepithelial Neoplasia

PURPOSE

Tamoxifen administered for 5 years at 20 mg/d is effective in breast cancer treatment and prevention, but toxicity has limited its broad use. Biomarker trials showed that 5 mg/d is not inferior to 20 mg/d in decreasing breast cancer proliferation. We hypothesized that a lower dose given for a shorter period could be as effective in preventing recurrence from breast intraepithelial neoplasia but have a lower toxicity than the standard dose.

PATIENTS AND METHODS

We conducted a multicenter randomized trial of tamoxifen, 5 mg/d or placebo administered for 3 years after surgery in women with hormone-sensitive or unknown breast intraepithelial neoplasia, including atypical ductal hyperplasia and lobular or ductal carcinoma in situ. The primary end point was the incidence of invasive breast cancer or ductal carcinoma in situ.

RESULTS

Five hundred women 75 years of age or younger were included. After a median follow-up of 5.1 years (interquartile range, 3.9-6.3 years), there were 14 neoplastic events with tamoxifen and 28 with placebo (11.6 v 23.9 per 1,000 person-years; hazard ratio, 0.48; 95% CI, 0.26 to 0.92; P = .02), which resulted in a 5-year number needed to treat of 22 (95% CI, 20 to 27). Tamoxifen decreased contralateral breast events by 75% (three v 12 events; hazard ratio, 0.25; 95% CI, 0.07 to 0.88; P = .02). Patient-reported outcomes were not different between arms except for a slight increase in frequency of daily hot flashes with tamoxifen (P = .02). There were 12 serious adverse events with tamoxifen and 16 with placebo, including one deep vein thrombosis and one stage I endometrial cancer with tamoxifen and one pulmonary embolism with placebo.

CONCLUSION

Tamoxifen at 5 mg/d for 3 years can halve the recurrence of breast intraepithelial neoplasia with a limited toxicity, which provides a new treatment option in these disorders.

Quality of Life in a Randomized Breast Cancer Prevention Trial of Low-Dose Tamoxifen and Fenretinide in Premenopausal Women

Menopausal symptoms are the main reason for withdrawal in tamoxifen prevention trials. Here, we present Menopause Quality of Life (MenQoL) assessment within a randomized 2 × 2 phase II clinical trial of low-dose tamoxifen and the synthetic retinoid fenretinide. A total of 235 premenopausal women at higher risk for breast cancer were randomized to either tamoxifen 5 mg daily, fenretinide 200 mg daily, their combination, or placebo. Climacteric symptoms were investigated using the MenQoL questionnaire which was self-administered at each visit for 2 years of treatment and for 1 year of follow-up. CYP2D6 was genotyped in subjects taking tamoxifen to study the association with menopausal symptoms. The MenQoL effect size analysis showed no statistically significant difference among the four treatment arms for all four domains (vasomotor, physical, psychosocial, and sexual). Vasomotor symptoms only slightly increased under tamoxifen, with a score at year two of 1.45, 1.21, 0.58, and 1.17 in the combined, tamoxifen, fenretinide, and placebo arms, respectively. Compared with the slow metabolizers, a higher percentage of subjects with CYP2D6 extensive metabolizer genotype complained of a ≥3 score in the vasomotor, psychosocial, and sexual domain in the tamoxifen arms (P value = 0.01, 0.007, and 0.007, respectively). QoL in premenopausal or perimenopausal women was not significantly worsened by low-dose tamoxifen or fenretinide. Our findings suggest that a low dose of tamoxifen may increase its acceptability for breast cancer prevention.

Bridging the Data Gap in Breast Cancer Risk Assessment to Enable Widespread Clinical Implementation across the Multiethnic Landscape of the US

Breast cancer remains the second leading cause of cancer death among women and is the most commonly diagnosed cancer in women. Breast cancer risk assessment has been clinically available for nearly 30 years yet is under-utilized in practice for multiple reasons. Incorporation of polygenic risk as well as breast density measurements, promise to increase the accuracy of risk assessment. With that comes the hope that both prevention and screening become more personalized and thus more effective. Incidence rates have been static over the past 15 years and have even increased slightly in African American and Asian/Pacific Islander populations despite the robust data on breast cancer risk reduction measures that exist. Current challenges in reducing breast cancer incidence begin with robust data curation that allows for appropriate risk stratification across our multiethnic population and conclude with the implementation of prevention strategies within our fractured healthcare system.