Making informed choices on incorporating chemoprevention into carE (MiCHOICE, SWOG 1904): Design and methods of a cluster randomized controlled trial

INTRODUCTION

Women with atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS) have a significantly increased risk of breast cancer, which can be substantially reduced with antiestrogen therapy for chemoprevention. However, antiestrogen therapy for breast cancer risk reduction remains underutilized. Improving knowledge about breast cancer risk and chemoprevention among high-risk patients and their healthcare providers may enhance informed decision-making about this critical breast cancer risk reduction strategy.

METHODS/DESIGN

We are conducting a cluster randomized controlled trial to evaluate the effectiveness and implementation of patient and provider decision support tools to improve informed choice about chemoprevention among women with AH or LCIS. We have cluster randomized 26 sites across the U.S. through the SWOG Cancer Research Network. A total of 415 patients and 200 healthcare providers are being recruited. They are assigned to standard educational materials alone or combined with the web-based decision support tools. Patient-reported and clinical outcomes are assessed at baseline, after a follow-up visit at 6 months, and yearly for 5 years. The primary outcome is chemoprevention informed choice after the follow-up visit. Secondary endpoints include other patient-reported outcomes, such as chemoprevention knowledge, decision conflict and regret, and self-reported chemoprevention usage. Barriers and facilitators to implementing decision support into clinic workflow are assessed through patient and provider interviews at baseline and mid-implementation.

RESULTS/DISCUSSION

With this hybrid effectiveness/implementation study, we seek to evaluate if a multi-level intervention effectively promotes informed decision-making about chemoprevention and provide valuable insights on how the intervention is implemented in U.S.

CLINICAL SETTINGS

TRIAL REGISTRATION

NCT04496739.

Epithelial Expressed B7-H4 Drives Differential Immunotherapy Response in Murine and Human Breast Cancer

Combinations of immune checkpoint inhibitors (ICI, including anti-PD-1/PD-L1) and chemotherapy have been FDA approved for metastatic and early-stage triple-negative breast cancer (TNBC), but most patients do not benefit. B7-H4 is a B7 family ligand with proposed immunosuppressive functions being explored as a cancer immunotherapy target and may be associated with anti-PD-L1 resistance. However, little is known about its regulation and effect on immune cell function in breast cancers. We assessed murine and human breast cancer cells to identify regulation mechanisms of B7-H4 in vitro. We used an immunocompetent anti-PD-L1-sensitive orthotopic mammary cancer model and induced ectopic expression of B7-H4. We assessed therapy response and transcriptional changes at baseline and under treatment with anti-PD-L1. We observed B7-H4 was highly associated with epithelial cell status and transcription factors and found to be regulated by PI3K activity. EMT6 tumors with cell-surface B7-H4 expression were more resistant to immunotherapy. In addition, tumor-infiltrating immune cells had reduced immune activation signaling based on transcriptomic analysis. Paradoxically, in human breast cancer, B7-H4 expression was associated with survival benefit for patients with metastatic TNBC treated with carboplatin plus anti-PD-L1 and was associated with no change in response or survival for patients with early breast cancer receiving chemotherapy plus anti-PD-1. While B7-H4 induces tumor resistance to anti-PD-L1 in murine models, there are alternative mechanisms of signaling and function in human cancers. In addition, the strong correlation of B7-H4 to epithelial cell markers suggests a potential regulatory mechanism of B7-H4 independent of PD-L1.

SIGNIFICANCE

This translational study confirms the association of B7-H4 expression with a cold immune microenvironment in breast cancer and offers preclinical studies demonstrating a potential role for B7-H4 in suppressing response to checkpoint therapy. However, analysis of two clinical trials with checkpoint inhibitors in the early and metastatic settings argue against B7-H4 as being a mechanism of clinical resistance to checkpoints, with clear implications for its candidacy as a therapeutic target.

NKG2A Is a Therapeutic Vulnerability in Immunotherapy Resistant MHC-I Heterogeneous Triple-Negative Breast Cancer

Despite the success of immune checkpoint inhibition (ICI) in treating cancer, patients with triple-negative breast cancer (TNBC) often develop resistance to therapy, and the underlying mechanisms are unclear. MHC-I expression is essential for antigen presentation and T-cell-directed immunotherapy responses. This study demonstrates that TNBC patients display intratumor heterogeneity in regional MHC-I expression. In murine models, loss of MHC-I negates antitumor immunity and ICI response, whereas intratumor MHC-I heterogeneity leads to increased infiltration of natural killer (NK) cells in an IFNγ-dependent manner. Using spatial technologies, MHC-I heterogeneity is associated with clinical resistance to anti-programmed death (PD) L1 therapy and increased NK:T-cell ratios in human breast tumors. MHC-I heterogeneous tumors require NKG2A to suppress NK-cell function. Combining anti-NKG2A and anti-PD-L1 therapies restores complete response in heterogeneous MHC-I murine models, dependent on the presence of activated, tumor-infiltrating NK and CD8+ T cells. These results suggest that similar strategies may enhance patient benefit in clinical trials.

SIGNIFICANCE

Clinical resistance to immunotherapy is common in breast cancer, and many patients will likely require combination therapy to maximize immunotherapeutic benefit. This study demonstrates that heterogeneous MHC-I expression drives resistance to anti-PD-L1 therapy and exposes NKG2A on NK cells as a target to overcome resistance. This article is featured in Selected Articles from This Issue, p. 201.

Atezolizumab in Combination With Carboplatin and Survival Outcomes in Patients With Metastatic Triple-Negative Breast Cancer: The TBCRC 043 Phase 2 Randomized Clinical Trial

Importance

Agents targeting programmed death ligand 1 (PD-L1) have demonstrated efficacy in triple-negative breast cancer (TNBC) when combined with chemotherapy and are now the standard of care in patients with PD-L1-positive metastatic disease. In contrast to microtubule-targeting agents, the effect of combining platinum compounds with programmed cell death 1 (PD-1)/PD-L1 immunotherapy has not been extensively determined.

Objective

To evaluate the efficacy of atezolizumab with carboplatin in patients with metastatic TNBC.

Design, Setting, and Participants

This phase 2 randomized clinical trial was conducted in 6 centers from August 2017 to June 2021.

Interventions

Patients with metastatic TNBC were randomized to receive carboplatin area under the curve (AUC) 6 alone or with atezolizumab, 1200 mg, every 3 weeks until disease progression or unacceptable toxic effects with a 3-year duration of follow-up.

Main Outcome and Measures

The primary end point was investigator-assessed progression-free survival (PFS). Secondary end points included overall response rate (ORR), clinical benefit rate (CBR), and overall survival (OS). Other objectives included correlation of response with tumor PD-L1 levels, tumor-infiltrating lymphocytes (TILs), tumor DNA- and RNA-sequenced biomarkers, TNBC subtyping, and multiplex analyses of immune markers.

Results

All 106 patients with metastatic TNBC who were enrolled were female with a mean (range) age of 55 (27-79) years, of which 12 (19%) identified as African American/Black, 1 (1%) as Asian, 73 (69%) as White, and 11 (10%) as unknown. Patients were randomized and received either carboplatin (n = 50) or carboplatin and atezolizumab (n = 56). The combination improved PFS (hazard ratio [HR], 0.66; 95% CI, 0.44-1.01; P = .05) from a median of 2.2 to 4.1 months, increased ORR from 8.0% (95% CI, 3.2%-18.8%) to 30.4% (95% CI, 19.9%-43.3%), increased CBR at 6 months from 18.0% (95% CI, 9.8%-30.1%) to 37.5% (95% CI, 26.0%-50.6%), and improved OS (HR, 0.60; 95% CI, 0.37-0.96; P = .03) from a median of 8.6 to 12.6 months. Subgroup analysis showed PD-L1-positive tumors did not benefit more from adding atezolizumab (HR, 0.62; 95% CI, 0.23-1.65; P = .35). Patients with high TILs (HR, 0.12; 95% CI, 0.30-0.50), high mutation burden (HR, 0.50; 95% CI, 0.23-1.06), and prior chemotherapy (HR, 0.59; 95% CI, 0.36-0.95) received greater benefit on the combination. Patients with obesity and patients with more than 125 mg/dL on-treatment blood glucose levels were associated with better PFS (HR, 0.35; 95% CI, 0.10-1.80) on the combination. TNBC subtypes benefited from adding atezolizumab, except the luminal androgen receptor subtype.

Conclusions and Relevance

In this randomized clinical trial, the addition of atezolizumab to carboplatin significantly improved survival of patients with metastatic TNBC regardless of PD-L1 status. Further, lower risk of disease progression was associated with increased TILs, higher mutation burden, obesity, and uncontrolled blood glucose levels.

Trial Registration

ClinicalTrials.gov Identifier: NCT03206203.

Molecular and clinical effects of aromatase inhibitor therapy on skeletal muscle function in early-stage breast cancer

We evaluated biochemical changes in skeletal muscle of women with breast cancer initiating aromatase inhibitors (AI), including oxidation of ryanodine receptor RyR1 and loss of stabilizing protein calstabin1, and detailed measures of muscle function. Fifteen postmenopausal women with stage I-III breast cancer planning to initiate AI enrolled. Quadriceps muscle biopsy, dual-energy x-ray absorptiometry, isokinetic dynamometry, Short Physical Performance Battery, grip strength, 6-min walk, patient-reported outcomes, and serologic measures of bone turnover were assessed before and after 6 months of AI. Post-AI exposure, oxidation of RyR1 significantly increased (0.23 ± 0.37 vs. 0.88 ± 0.80, p < 0.001) and RyR1-bound calstabin1 significantly decreased (1.69 ± 1.53 vs. 0.74 ± 0.85, p < 0.001), consistent with dysfunctional calcium channels in skeletal muscle. Grip strength significantly decreased at 6 months. No significant differences were seen in isokinetic dynamometry measures of muscle contractility, fatigue resistance, or muscle recovery post-AI exposure. However, there was significant correlation between oxidation of RyR1 with muscle power (r = 0.60, p = 0.02) and muscle fatigue (r = 0.57, p = 0.03). Estrogen deprivation therapy for breast cancer resulted in maladaptive changes in skeletal muscle, consistent with the biochemical signature of dysfunctional RyR1 calcium channels. Future studies will evaluate longer trajectories of muscle function change and include other high bone turnover states, such as bone metastases.

Racial Disparities in Breast Cancer: from Detection to Treatment

PURPOSE OF REVIEW

Update on current racial disparities in the detection and treatment of breast cancer.

RECENT FINDINGS

Breast cancer remains the leading cause of cancer death among Black and Hispanic women. Mammography rates among Black and Hispanic women have surpassed those among White women, with studies now advocating for earlier initiation of breast cancer screening in Black women. Black, Hispanic, Asian, and American Indian and Alaskan Native women continue to experience delays in diagnosis and time to treatment. Further, racial discrepancies in receipt of guideline-concordant care, access to genetic testing and surgical reconstruction persist. Disparities in the initiation, completion, toxicity, and efficacy of chemotherapy, endocrine therapy, and targeted drug therapy remain for racially marginalized women. Efforts to evaluate the impact of race and ethnicity across the breast cancer spectrum are increasing, but knowledge gaps remain and further research is necessary to reduce the disparity gap.

Impact of Muscle Measures on Outcome in Patients Receiving Endocrine Therapy for Metastatic Breast Cancer: Analysis of ECOG-ACRIN E2112

BACKGROUND

Observational data investigating the relationship between body habitus and outcomes in breast cancer have been variable and inconsistent, largely centered in the curative setting and focused on weight-based metrics. This study evaluated the impact of muscle measures on outcomes in patients with metastatic breast cancer receiving endocrine-based therapy.

METHODS

Baseline CT scans were collected from ECOG-ACRIN E2112, a randomized phase III placebo-controlled study of exemestane with or without entinostat. A CT cross-sectional image at the L3 level was extracted to obtain skeletal muscle mass and attenuation. Low muscle mass (LMM) was defined as skeletal muscle index <41 cm2/m2 and low muscle attenuation (LMA) as muscle density <25 HU or <33 HU if overweight/obese by body mass index (BMI). Multivariable Cox proportional hazard models determined the association between LMM or LMA and progression-free survival (PFS) and overall survival (OS). Correlations between LMM, LMA, and patient-reported outcomes were determined using 2-sample t tests.

RESULTS

Analyzable CT scans and follow-up data were available for 540 of 608 patients. LMM was present in 39% (n=212) of patients and LMA in 56% (n=301). Those with LMA were more likely to have obesity and worse performance status. LMM was not associated with survival (PFS hazard ratio [HR]: 1.13, P=.23; OS HR: 1.05, P=.68), nor was LMA (PFS HR: 1.01, P=.93; OS HR: 1.00, P=.99). BMI was not associated with survival. LMA, but not LMM, was associated with increased frequency of patient-reported muscle aches.

CONCLUSIONS

Both low muscle mass and density are prevalent in patients with hormone receptor-positive metastatic breast cancer. Muscle measures correlated with obesity and performance status; however, neither muscle mass nor attenuation were associated with prognosis. Further work is needed to refine body composition measurements and select optimal cutoffs with meaningful endpoints in specific breast cancer populations, particularly those living with metastatic disease.

Racial disparities in cascade testing for cancer predisposition genes

We sought to determine whether there are racial disparities in cascade testing rates and whether providing testing at no-charge impacts rates in Black and White at-risk-relatives (ARR). Probands with a pathogenic/likely pathogenic germline variant in a cancer predisposition gene were identified up to one year before and up to one year after cascade testing became no-charge in 2017. Cascade testing rates were measured as the proportion of probands who had at least one ARR obtain genetic testing through one commercial laboratory. Rates were compared between self-reported Black and White probands using logistic regression. Interaction between race and cost (pre/post policy) was tested. Significantly fewer Black probands than White probands had at least one ARR undergo cascade genetic testing (11.9% versus 21.7%, OR 0.49, 95% CI 0.39-0.61, p < 0.0001). This was seen both before (OR 0.38, 95% CI 0.24-0.61, p < 0.001) and after (OR 0.53, 95% CI 0.41-0.68, p < 0.001) the no-charge testing policy. Rates of an ARR undergoing cascade testing were low overall, and significantly lower in Black versus White probands. The magnitude of difference in cascade testing rates between Blacks and Whites did not significantly change with no-charge testing. Barriers to cascade testing in all populations should be explored in order to maximize the benefits of genetic testing for both treatment and prevention of cancer.

Imaging modalities for measuring body composition in patients with cancer: opportunities and challenges

Body composition assessment (ie, the measurement of muscle and adiposity) impacts several cancer-related outcomes including treatment-related toxicities, treatment responses, complications, and prognosis. Traditional modalities for body composition measurement include body mass index, body circumference, skinfold thickness, and bioelectrical impedance analysis; advanced imaging modalities include dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and positron emission tomography. Each modality has its advantages and disadvantages, thus requiring an individualized approach in identifying the most appropriate measure for specific clinical or research situations. Advancements in imaging approaches have led to an abundance of available data, however, the lack of standardized thresholds for classification of abnormal muscle mass or adiposity has been a barrier to adopting these measurements widely in research and clinical care. In this review, we discuss the different modalities in detail and provide guidance on their unique opportunities and challenges.

Association of Allostatic Load With All-Cause Mortality in Patients With Breast Cancer

Importance

Elevated allostatic load (AL) has been associated with adverse socioenvironmental stressors and tumor characteristics that convey poor prognosis in patients with breast cancer. Currently, the association between AL and all-cause mortality in patients with breast cancer is unknown.

Objective

To examine the association between AL and all-cause mortality in patients with breast cancer.

Design, Setting, and Participants

This cohort study used data from an institutional electronic medical record and cancer registry at the National Cancer Institute Comprehensive Cancer Center. Participants were patients with breast cancer diagnoses (stage I-III) between January 1, 2012, through December 31, 2020. Data were analyzed from April 2022 through November 2022.

Exposure

AL was expressed as a summary score calculated by assigning 1 point for biomarkers in the worst sample quartile. High AL was defined as AL greater than the median.

Main Outcomes and Measures

The main outcome was all-cause mortality. A Cox proportional hazard models with robust variance tested the association between AL and all-cause mortality.

Results

There were 4459 patients (median [IQR] age, 59 [49-67] years) with an ethnoracial distribution of 3 Hispanic Black patients (0.1%), 381 non-Hispanic Black patients (8.5%), 23 Hispanic White patients (0.5%), 3861 non-Hispanic White patients (86.6%), 27 Hispanic patients with other race (0.6%), and 164 non-Hispanic patients with other race (3.7%). The mean (SD) AL was 2.6 (1.7). Black patients (adjusted relative ratio [aRR], those with 1.11; 95% CI, 1.04-1.18), single marital status (aRR, 1.06; 95% CI, 1.00-1.12), and those with government-supplied insured (Medicaid aRR, 1.14; 95% CI, 1.07-1.21; Medicare aRR, 1.11; 95% CI, 1.03-1.19) had a higher adjusted mean AL than those who were White, married/living as married, or privately insured, respectively. Adjusting for sociodemographic, clinical, and treatment factors, high AL was associated with a 46% increase in mortality risk (hazard ratio [HR], 1.46; 95% CI, 1.11-1.93) over low AL. Similarly, compared with patients in the first AL quartile, those in the third quartile (HR, 1.53; 95% CI, 1.07-2.18) and the fourth quartile (HR, 1.79; 95% CI, 1.16-2.75) had significantly increased risks of mortality. There was a significant dose-dependent association between increased AL and a higher risk of all-cause mortality. Furthermore, AL remained significantly associated with higher all-cause mortality after adjusting for the Charlson Comorbidity Index.

Conclusions and Relevance

These findings suggest increased AL is reflective of socioeconomic marginalization and associated with all-cause mortality in patients with breast cancer.

Abstract OT1-15-01: SWOG 1904: Cluster-randomized controlled trial of patient and provider decision support to increase chemoprevention informed choice among women with atypical hyperplasia or lobular carcinoma in situ (MiCHOICE)

Background: Despite evidence of substantial breast cancer risk reduction, few high-risk women adopt chemopreventive medications such as selective estrogen receptor modulators (SERMs) or aromatase inhibitors (AIs). Women with benign breast disease, such as atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS), have an increased risk of developing breast cancer and derive a greater benefit from antiestrogens compared to other high-risk women. Reasons for low uptake of chemoprevention include insufficient patient and clinician knowledge about antiestrogens, time constraints during the clinical encounter, and concerns about side effects. To address these barriers, we have developed patient and provider web-based decision support tools to improve informed choice about breast cancer chemoprevention among women with AH or LCIS. Study design: We are conducting a cluster-randomized controlled trial of clinical decision support to improve chemoprevention informed choice among women with AH or LCIS and their treating providers. Twenty-six U.S. sites through the SWOG Cancer Research Network were randomly assigned 1:1 to standard educational materials alone or in combination with the patient-centered decision aid (RealRisks) and provider decision support tool (BNAV). A total of 415 patients and 200 healthcare providers will be recruited from these sites. RealRisks consists of interactive modules to calculate personalized breast cancer risk and elicit preferences on chemoprevention. The modules are available in English and Spanish. BNAV is comprised of self-directed case-based learning modules on breast cancer risk assessment and chemoprevention. Patients complete questionnaires at baseline, 6 and 12 months. Providers complete surveys at baseline and after their enrolled patient’s 6-month clinical encounter. The primary endpoint is chemoprevention informed choice at 6 months, using a measure combining knowledge, attitude, and intention scales. Secondary endpoints include perceived breast cancer risk/worry, chemoprevention knowledge/intention, decision conflict/regret, shared decision-making, and chemoprevention uptake. For patients who begin chemoprevention, adherence and reasons for discontinuation are assessed annually for up to 5 years. Barriers and facilitators to implementing RealRisks and BNAV into clinic workflow will be assessed by conducting patient and provider interviews at baseline and mid-implementation. Eligibility criteria: Eligible patients include women, age 35-74 years, with AH or LCIS, no history of breast cancer, no prior use of SERMs or AIs, no bilateral mastectomies, English or Spanish-speaking, and access to the internet. Eligible providers include breast surgeons, medical oncologists, primary care providers, and physician extenders who see patients with AH or LCIS. Statistical methods: We have 90% power to detect a 15% increase in the frequency of chemoprevention informed choice with a 1-sided 0.025 level test, assuming an intraclass correlation (ICC) of 0.02 to account for clustering, roughly equal accrual at each site, 10% loss to follow-up, and ≤10% event rate in the control arm. Current/target accrual: The trial was activated on 9/1/2020. As of 7/7/2022, all 26 sites have been randomized, 157/200 providers and 184/415 patients have been enrolled. Discussion: Our hybrid effectiveness/implementation study seeks to evaluate the effectiveness of a multi-level intervention in promoting informed decision-making about breast cancer chemoprevention. Study results will provide valuable insights on how the decision support tools are integrated in diverse clinical settings.

Citation Format: Katherine D. Crew, Garnet Anderson, Kathryn Arnold, Andrew Stieb, Jacquelyn N. Amenta, Cynthia Law, Ana Sandoval-Leon, Sarah Colonna, Tari King, Debra Mangino, Sandhya Pruthi, Maria Grosse Perdekamp, Christa Braun-Inglis, Stacy Krisher, Lisa Yee, Danielle Bertoni, Samantha Seaward, Kari B. Wisinski, Justin Floyd, Corrine Zarwan, Tarah J. Ballinger, Lindi VanderWalde, Masey M. Ross, Preston Steen, Shelly Lo, Alison Conlin, Kathleen Yost, John Ellerton, Erin Lin, Holly J. Pederson, Sagar Sardesai, Cheryl Jernigan, Dawn Hershman, Marian L. Neuhouser, Banu K. Arun, Rita Kukafka. SWOG 1904: Cluster-randomized controlled trial of patient and provider decision support to increase chemoprevention informed choice among women with atypical hyperplasia or lobular carcinoma in situ (MiCHOICE) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-15-01.

Abstract P3-05-26: Association of muscle mass and density with outcomes in patients with ER positive metastatic breast cancer: correlative analysis of ECOG-ACRIN 2112

Introduction: Observational data investigating the relationship between body habitus and survival or toxicity in breast cancer has been largely centered in the curative setting and focused on weight- based metrics, with variable and inconsistent results. Muscle is a large, active endocrine organ that affects physical function, drug metabolism, inflammation, and quality of life, but is not adequately measured by body weight alone. Very few studies have evaluated muscle measures in metastatic breast cancer (MBC) and have been focused on patients receiving cytotoxic chemotherapy. Here, we evaluate the impact of muscle mass and muscle density measured on CT scan on outcomes in patients with MBC receiving endocrine- based therapy. Methods: Baseline CT scans done at the time of study enrollment were centrally collected from participants in ECOG-ACRIN E2112, a randomized phase III study of exemestane with or without entinostat in MBC, which ultimately did not impact survival. A transverse cut at the L3 level was extracted and processed using semi-automated SliceOmatic software (Tomovision) by two independent investigators to obtain total body skeletal muscle mass and muscle attenuation. Low muscle mass was defined as skeletal muscle index (SMI, lean muscle area/height, cm2/m2) less than 41 and low skeletal muscle attenuation (SMA) was defined as average muscle density less than 41 HU, or less than 33 HU if the patient is overweight or obese by BMI. Chi-square tests were used to determine the association between SMI and SMA and other clinical characteristics, including body weight, race, and performance status. Multivariable Cox proportional hazard models were used to determine the association between low SMI or low SMA and overall survival (OS), progression free survival (PFS), and patient- reported outcomes. Results: Of the 608 patients randomized in E2112, 546 had analyzable CT scans and follow up data available. 45% (n=246) of participants had obesity by BMI (≥30); 39% (n=212) had low SMI and 56% (n=305) had low SMA. Obese patients were more likely to have higher SMI (p&lt; 0.001); however, 9.5% (n=52) of the study population had both obesity and low SMI. Low SMA was associated with higher rate of obesity and worse performance status (p&lt; 0.001), consistent with muscle quality being a predictor of functional status. Low SMI was not associated with survival outcomes (OS HR 1.04 95%CI 0.83-1.30, PFS HR 1.12 95% CI 0.92-1.36), nor was low SMA (OS HR 1.02 95%CI 0.81-1.28; PFS HR 1.02 95%CI 0.84-1.23). In addition, BMI was not related to survival outcomes. Conclusions: Low muscle mass and low muscle density are prevalent in estrogen receptor positive MBC patients. Muscle measures correlated with obesity and performance status; however, neither low SMI nor low SMA were associated with worse prognosis in this population. Further work is needed to refine body composition measurements and select optimal cutoffs and meaningful endpoints in specific breast cancer populations, particularly in those living with metastatic disease.

Citation Format: Tarah J. Ballinger, Gloria Xue, Helga S. Marques, Constantine Gatsonis, Richard Hoffman, Kathy D. Miller, Fengmin Zhao, Joseph Sparano, Roisin Connolly. Association of muscle mass and density with outcomes in patients with ER positive metastatic breast cancer: correlative analysis of ECOG-ACRIN 2112 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-26.

Energy balance in advanced breast cancer: extending beyond the curative setting

Outcomes in early-stage breast cancer, including quality of life, body composition, physical functioning, physiologic biomarkers, cancer recurrence, and mortality, are associated with body weight, diet, and physical activity. These same endpoints may also be relevant in patients with metastatic breast cancer; however, few studies have evaluated the role of energy balance in this setting. Future work is needed to determine how body weight, nutrition, and exercise or other physical activity might affect the disease course of metastatic breast cancer, and whether energy balance may be a component of beneficial supportive or therapeutic interventions for specific patient populations living with metastatic breast cancer.

The bone-muscle connection in breast cancer: implications and therapeutic strategies to preserve musculoskeletal health

Breast cancer and its therapies frequently result in significant musculoskeletal morbidity. Skeletal complications include bone metastases, pain, bone loss, osteoporosis, and fracture. In addition, muscle loss or weakness occurring in both the metastatic and curative setting is becoming increasingly recognized as systemic complications of disease and treatment, impacting quality of life, responsiveness to therapy, and survival. While the anatomical relationship between bone and muscle is well established, emerging research has led to new insights into the biochemical and molecular crosstalk between the skeletal and muscular systems. Here, we review the importance of both skeletal and muscular health in breast cancer, the significance of crosstalk between bone and muscle, and the influence of mechanical signals on this relationship. Therapeutic exploitation of signaling between bone and muscle has great potential to prevent the full spectrum of musculoskeletal complications across the continuum of breast cancer.

Proton Pump Inhibitor Use and Obesity-Associated Cancer in the Women's Health Initiative

Proton pump inhibitors (PPIs) have off-target activity on fatty acid synthase (FASN), a critical enzyme in energy balance and cancer growth. We evaluated risk of common obesity-related cancers: breast, colorectal (CRC), and endometrial, with use of PPI and histamine-2 receptor antagonists (H2RA) in 124,931 postmenopausal women enrolled in the Women's Health Initiative. Incident cancer cases were physician-adjudicated. Cox proportional hazards models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for cancer incidence after year 3. There were 7956 PPI ever users and 9398 H2RA only users. Ever use of either PPI or H2RA was not associated with risk of breast cancer (n = 9186) nor risk of endometrial cancer (n = 1231). The risk of CRC (n = 2280) was significantly lower in PPI users (HR = 0.75, 95% CI = 0.61-0.92), but not in H2RA users (HR = 1.13, 95% CI = 0.97-1.31). The association of PPI use with CRC was apparent regardless of BMI or NSAID use, and was stronger with longer PPI duration (p = 0.006) and potency (p = 0.005). The findings that PPI use, but not H2RA use, demonstrate an inverse dose-response relationship with risk of CRC is consistent with preclinical data showing FASN inhibition prevents colon cancer progression and supports a role of PPI in CRC prevention.

Initial Phase I Safety Study of Gedatolisib plus Cofetuzumab Pelidotin for Patients with Metastatic Triple-Negative Breast Cancer

PURPOSE

The PI3K pathway is dysregulated in the majority of triple-negative breast cancers (TNBC), yet single-agent inhibition of PI3K has been ineffective in TNBC. PI3K inhibition leads to an immediate compensatory upregulation of the Wnt pathway. Dual targeting of both pathways is highly synergistic against TNBC models in vitro and in vivo. We initiated a phase I clinical trial combining gedatolisib, a pan-class I isoform PI3K/mTOR inhibitor, and cofetuzumab pelidotin, an antibody-drug conjugate against the cell-surface PTK7 protein (Wnt pathway coreceptor) with an auristatin payload.

PATIENTS AND METHODS

Participants (pt) had metastatic TNBC or estrogen receptor (ER) low (ER and PgR < 5%, HER2-negative) breast cancer, and had received at least one prior chemotherapy for advanced disease. The primary objective was safety. Secondary endpoints included overall response rate (ORR), clinical benefit at 18 weeks (CB18), progression-free survival (PFS), and correlative analyses.

RESULTS

A total of 18 pts were enrolled in three dose cohorts: gedatolisib 110 mg weekly + cofetuzumab pelidotin 1.4 mg/kg every 3 weeks (n = 4), 180 mg + 1.4 mg/kg (n = 3), and 180 mg + 2.8 mg/kg (n = 11). Nausea, anorexia, fatigue, and mucositis were common but rarely reached ≥grade 3 severity. Myelosuppression was uncommon. ORR was 16.7% (3/18). An additional 3 pts had stable disease (of these 2 had stable disease for >18 weeks); CB18 was 27.8%. Median PFS was 2.0 months (95% confidence interval for PFS: 1.2-6.2). Pts with clinical benefit were enriched with genomic alterations in the PI3K and PTK7 pathways.

CONCLUSIONS

The combination of gedatolisib + cofetuzumab pelidotin was well tolerated and demonstrated promising clinical activity. Further investigation of this drug combination in metastatic TNBC is warranted.

Racial Disparities in Family Variant Testing for Cancer Predisposition Genes

PURPOSE

Despite the substantial clinical impact of genetic testing, racial disparities exist in the delivery of this service. Here, we partnered with a commercial laboratory (Invitae) to establish whether there are racial disparities in the uptake of family variant testing (FVT). We also investigated if providing FVT at no cost impacts rates of cascade testing in Black and White families.

METHODS

This is a retrospective analysis comparing rates of FVT in self-reporting Black probands to self-reporting White probands who underwent germline genetic testing for genes associated with hereditary cancer through Invitae. All Black and White patients found to have a pathogenic/likely pathogenic variant P/LPV) in a hereditary cancer syndrome gene were identified up to one year before and up to one year after FVT became no-charge in 1/2017. The proportion of probands with at least one at- risk family member who underwent FVT was compared between Black and White probands using logistic regression, including the interaction between covariates of cost and race.

RESULTS

Between 1/2016 and 1/2018, 8,530 Black and 87,846 White probands underwent genetic testing. Of these, 9.3% (n =791) Black probands and 11.4% (n=9,998) White probands had a P/LPV identified. The uptake of FVT, defined by percentage of positive probands with at least one family member undergoing testing, was significantly lower in Black participants compared to White participants (11.9% versus 21.7%, odds ratio 0.5, 95% CI 0.4-0.6, p<0.001). Period of testing before or after FVT was no-charge did not impact this difference (p=0.23 for the interaction). FVT rates were significantly lower in Black patients compared to White patients both before (8.1% versus 18.7%, OR 0.4, 95% CI 0.2-0.6, p<0.001) and after (13.6% versus 23.1%, OR 0.5, 95% CI 0.4-0.7, p<0.001) testing became no-charge.

CONCLUSION

While FVT rates were low overall, they were significantly lower in Black families compared to White families. Cost of FVT did not have a significant impact on the racial disparity seen, suggesting additional barriers exist. Recognizing these disparities and determining the contributing factors are crucial to developing tailored interventions that would ultimately advance racial equity in cancer care.

Proton Pump Inhibitor Use and Obesity-Associated Cancers in the Women's Health Initiative

PURPOSE

Proton pump inhibitors (PPIs) inhibit fatty acid synthase (FAS), a critical enzyme in lipogenesis, energy balance, and cancer cell survival. We aimed to evaluate the association of PPI use with incidence of common obesity- related cancers in women: postmenopausal breast, colorectal, and endometrial cancers.

METHODS

Our study included 124,931 postmenopausal who were enrolled in the Women's Health Initiative (WHI) observational study and clinical trials, and had responded to a year 3 follow-up assessment. We examined prescription and over the counter use of PPI and/or histamine 2 receptor antagonists (H2RA) at baseline and year 3, to isolate potential effects of FAS inhibition by PPI rather than simply acid suppression. Incident cancer cases were physician-adjudicated. Cox proportional hazard regression models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for associations between PPI and/or H2RA use and cancer incidence after year 3.

RESULTS

There were 7956 PPI ever users (with or without H2RA use) and 9398 H2RA only users. PPI or H2RA use was not associated with risk of breast cancer (n=9186 cases), compared to women who did not use either agent (HR 1.01, 95% CI 0.93-1.10 and HR 0.95 95% CI 0.87-1.03, respectively). The incidence of colorectal cancer (n=2280) was significantly lower in PPI users (HR 0.75, 95% CI 0.61-0.92), but not in H2RA users (HR 1.13, 95% CI 0.97-1.31). This association was strengthened with increasing duration (p=0.006) and potency (p=0.005) of PPI use and held regardless of BMI or NSAID use. PPI or H2RA use was not associated with endometrial cancer (n=1231) (HR 0.81, 95% CI 0.61-1.07 and HR 1.13, 95% CI 0.91-1.40, respectively), but showed a trend in decreased risk with increasing PPI potency (P=0.048).

CONCLUSIONS

Among postmenopausal women, PPI use, but not H2RA use, demonstrated an inverse, dose-responsive association with colorectal cancer incidence. This was consistent with preclinical data that FAS inhibition prevents colon cancer progression and supports further investigation of this commonly used medication as a cancer preventive agent. PPI use was not associated with incidence of breast or endometrial cancer.

Impact of African ancestry on the relationship between body mass index and survival in an early-stage breast cancer trial (ECOG-ACRIN E5103)

BACKGROUND

African ancestry (AA) and obesity are associated with worse survival in early-stage breast cancer. Obesity disproportionately affects women of AA; however, the intersection between ancestry and obesity on breast cancer outcomes remains unclear.

METHODS

A total of 2854 patients in the adjuvant trial E5103 were analyzed. Genetic ancestry was determined using principal components from a genome-wide array. The impact of continuous or binary body mass index (BMI) on disease-free survival (DFS) and overall survival (OS) was evaluated by multivariable Cox proportional hazards models in AA patients and European ancestry (EA) patients.

RESULTS

There were 2471 EA patients and 383 AA patients. Higher BMI was significantly associated with worse DFS and OS only in AA patients (DFS hazard ratio [HR], 1.25; 95% CI, 1.07-1.46; OS HR, 1.38; 95% CI, 1.10-1.73), not in EA patients (DFS HR, 0.97; 95% CI, 0.90-1.05; OS HR, 1.03; 95% CI, 0.93-1.14). Severe obesity (BMI ≥40) was significantly associated with worse survival in AA patients (DFS HR, 2.04; 95% CI, 1.21-3.43; OS HR, 2.21; 95% CI, 1.03-4.75) but had no impact on that of EA patients. In the estrogen receptor-positive (ER+) and triple-negative breast cancer subgroups, BMI was significantly associated with worse outcomes only in those AA patients with ER+ disease. Within the AA group, BMI remained associated with worse survival regardless of the AA proportion.

CONCLUSIONS

Higher BMI was statistically significantly associated with worse breast cancer outcomes in AA but not EA patients. This association was most significant for severe obesity and those with ER+ disease. These observations help define optimal populations for weight change interventions designed to affect disparities and survival in early-stage breast cancer.

LAY SUMMARY

African ancestry and obesity are both risk factors for worse survival after early-stage breast cancer. Women of African descent are also disproportionately affected by obesity; however, it is unclear what impact body weight has on racial disparities in breast cancer. Data from a large phase 3 clinical trial in high-risk, early-stage breast cancer were used to determine how body weight affects survival outcomes in European versus African Americans. Study results demonstrate that a higher body mass index is associated with increased risk of breast cancer recurrence and worse survival in women of African ancestry but not in women of European ancestry.

Abstract PD9-10: BRE12-158: A post-neoadjuvant, randomized phase 2 trial of personalized therapy vs. treatment of physician’s choice for patients with residual triple negative breast cancer

Purpose: Patients with triple negative breast cancer (TNBC) with residual disease after neoadjuvant chemotherapy (NAC) have high risk of recurrence with prior data suggesting improved outcomes with capecitabine. Targeted agents have demonstrated activity across multiple cancer types. BRE12-158 was a phase 2, multicenter trial that randomized TNBC patients with residual disease after NAC to genomically-directed therapy vs. treatment of physician choice (TPC). Patients and Methods: From March 2014 to December 2018, 197 patients were enrolled. Residual tumors were sequenced using a next generation sequencing (NGS) test. A molecular tumor board adjudicated all results. Patients were randomized to 4 cycles of genomically-directed therapy (arm A) vs. TPC (arm B). Patients without a target were assigned to arm B. Primary endpoint was 2-year disease free survival (DFS) among randomized patients. Secondary/exploratory endpoints included: distant disease free survival (DDFS), overall survival (OS), toxicity assessment, time-based evolution of therapy, and drug-specific outcomes. Results: 193 patients were randomized or were assigned to arm B. The estimated 2-year DFS was 56.6% (95%CI:0.45-0.70) for arm A vs. 62.4% (95%CI:0.52-0.75) for randomized arm B. No difference was seen in DFS, DDFS, or OS for the entire or randomized populations. There was increased uptake of capecitabine for TPC over time. Patients randomized later had less distant recurrences. ctDNA status remained a significant predictor of outcome with some patients demonstrating clearance with post-neoadjuvant therapy. Conclusion: Genomically directed therapy was not superior to TPC for patients with residual TNBC after NAC. Capecitabine should remain the standard of care; however, the activity of other agents in this setting provides rationale for testing optimal combinations to improve outcomes for this high-risk population. ctDNA should be considered a standard covariate for trials in this setting.

Citation Format: Bryan P Schneider, Guanglong Jiang, Tarah J Ballinger, Fei Shen, Christopher Chitambar, Rita Nanda, Carla Falkson, Filipa C Lynce, Christopher Gallagher, Claudine Isaacs, Marcelo Blaya, Elisavet Paplomata, Radhika Walling, Karen Daily, Reshma Mahtani, Michael A Thompson, Robert Graham, Maureen E Cooper, Dean C Pavlick, Lee A Albacker, Jeffery Gregg, Jeffery P Solzak, Yu-Hsiang Chen, Casey L Bales, Erica Cantor, Bradley A Hancock, Nawal Kassem, Paul Helft, Bert O'Neil, Anna Maria Storniolo, Sunil Badve, Kathy D Miller, Milan Radovich. BRE12-158: A post-neoadjuvant, randomized phase 2 trial of personalized therapy vs. treatment of physician’s choice for patients with residual triple negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD9-10.

Physical activity and risk of benign proliferative epithelial disorders of the breast, in the Women's Health Initiative

BACKGROUND

Recreational physical activity (PA) has been shown to be inversely associated with breast cancer risk. However, the association of recreational PA with benign proliferative epithelial disorders (BPED) of the breast, conditions associated with increased risk of breast cancer, has not been adequately studied.

METHODS

We used data from an ancillary study of benign breast disease conducted among the 68 132 postmenopausal women (aged 50-79 at recruitment) participating in the Women's Health Initiative randomized clinical trials. All clinical trial participants underwent annual or biennial mammogram screening. During the follow-up, for women who reported breast biopsies but were cancer free, the associated histological sections were obtained and subjected to standardized central pathology review. Self-reported recreational PA at baseline (n = 61 684) and at 3 years of the follow-up (n = 55 923) were quantified as metabolic equivalents [MET]-h/week. There were 1624 confirmed BPED cases during an average follow-up time of 7.7 years. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Higher average PA over 4 years was associated with lower risk of non-atypical BPED (P-trend = 0.02). There was a 6% lower risk of non-atypical BPED for every 5 MET-h/week increase between baseline and year 3 (HR = 0.94, 95% CI 0.89-0.99). Compared with women who remained inactive (PAbaseline and PAyear3 <9 MET-h/week), those who became active (PAbaseline<9 MET-h/week to PAyear3 ≥9 MET-h/weekee), remained active (PAbaseline and PAyear3 ≥9 MET-h/week), or decreased activity (PAbaseline ≥9 MET-h/week to PAyear3 <9 MET-h/week) had lower BPED risk.

CONCLUSIONS

Recreational physical activity after menopause was associated with lower BPED risk among postmenopausal women.

BRE12-158: A Postneoadjuvant, Randomized Phase II Trial of Personalized Therapy Versus Treatment of Physician's Choice for Patients With Residual Triple-Negative Breast Cancer

PURPOSE

Patients with triple-negative breast cancer (TNBC) with residual disease after neoadjuvant chemotherapy (NAC) have high risk of recurrence with prior data suggesting improved outcomes with capecitabine. Targeted agents have demonstrated activity across multiple cancer types. BRE12-158 was a phase II, multicenter trial that randomly allocated patients with TNBC with residual disease after NAC to genomically directed therapy versus treatment of physician choice (TPC).

PATIENTS AND METHODS

From March 2014 to December 2018, 193 patients were enrolled. Residual tumors were sequenced using a next-generation sequencing test. A molecular tumor board adjudicated all results. Patients were randomly allocated to four cycles of genomically directed therapy (arm A) versus TPC (arm B). Patients without a target were assigned to arm B. Primary end point was 2-year disease-free survival (DFS) among randomly assigned patients. Secondary/exploratory end points included distant disease-free survival, overall survival, toxicity assessment, time-based evolution of therapy, and drug-specific outcomes.

RESULTS

One hundred ninety-three patients were randomly allocated or were assigned to arm B. The estimated 2-year DFS for the randomized population only was 56.6% (95% CI, 0.45 to 0.70) for arm A versus 62.4% (95% CI, 0.52 to 0.75) for arm B. No difference was seen in DFS, distant disease-free survival, or overall survival for the entire or randomized populations. There was increased uptake of capecitabine for TPC over time. Patients randomly allocated later had less distant recurrences. Circulating tumor DNA status remained a significant predictor of outcome with some patients demonstrating clearance with postneoadjuvant therapy.

CONCLUSION

Genomically directed therapy was not superior to TPC for patients with residual TNBC after NAC. Capecitabine should remain the standard of care; however, the activity of other agents in this setting provides rationale for testing optimal combinations to improve outcomes. Circulating tumor DNA should be considered a standard covariate for trials in this setting.

Exercise load monitoring: integrated approaches to advance the individualisation of exercise oncology

Whether slowing disease progression or combatting the ills of advancing age, the extensive utility of exercise training has contributed to the outright declaration by the American College of Sports Medicine that 'exercise is medicine'. Consistent with general framework of adaptation, the advantages of exercise training are indiscriminate-benefitting even the most susceptible clinical populations. Still, the benefit of exercise training presupposes healthy adaptation wherein progressive overload matches sufficient recovery. Indeed, a difference exists between healthy adaptation and non-functional over-reaching (ie, when internal/external load exceeds recovery capacity)-a difference that may be blurred by cancer treatment and/or comorbidity. Recent advances in smartwatches make them ideally suited to non-invasively monitor the physiological stresses to exercise training. Resolving whether individuals are successfully adapting to exercise training via load monitoring bears clinical and practical relevance. While behaviour-change research aims to identify positive constructs of exercise adherence, further attention is needed to uncover how to optimise exercise prescription among cancer populations. Herein, we briefly discuss the constituents of exercise load monitoring, present examples of internal and external load and consider how such practices can be applied to cancer populations.

Landmark trials in the medical oncology management of metastatic breast cancer

Significant advances in the management of metastatic breast cancer (MBC) have guided more personalized treatment according to disease biology and led to improved survival outcomes and quality of life for patients. In this review, we discuss landmark clinical trials in medical oncology that have shaped the current standard of care for MBC. Combinations of endocrine therapy with cyclin-dependent kinase 4/6 inhibitors have led to substantial improvements in overall survival, thus becoming standard first-line treatment for patients with HR-positive MBC. Inhibition of the PI3K and mTOR pathway is another promising strategy to overcome resistance to endocrine therapy. HER2-targeted therapies have also evolved with the addition of pertuzumab to trastuzumab plus a taxane demonstrating remarkable overall survival advantage in patient with HER2-positive MBC. In second or later line therapies, novel anti-HER2 antibody-drug conjugates and TKIs have durable antitumor activity, survival benefit, and encouraging efficacy in the subgroup of patients with brain metastases. Triple negative breast cancer remains the most challenging subtype due to lack of druggable targets. Immunotherapy for patients with PDL-1 expression on tumor infiltrating immune cells and poly (ADP-ribose) polymerase inhibitors for those with germline BRCA1/2 mutations are the latest approved targeted strategies in this population. Numerous obstacles still exist in treating MBC, especially for patients whose disease develops resistance to available agents. Future research is eagerly awaited to address the optimal sequence or combination of therapies and to identify better biomarkers to guide precision medicine.

A Personalized, Dynamic Physical Activity Intervention Is Feasible and Improves Energetic Capacity, Energy Expenditure, and Quality of Life in Breast Cancer Survivors

Purpose

Despite survival and quality of life benefits associated with physical activity, many breast cancer survivors remain inactive. Effective, sustainable interventions must account for individual differences in capability, motivation, and environment. Here, we evaluate the feasibility, mechanics, and efficacy of delivering an individualized, dynamic intervention to increase energetic capacity and energy expenditure.

Methods

Stage 0–III breast cancer patients who had completed primary treatment were enrolled. Prior to the intervention, detailed movement data was collected with a wearable GPS and accelerometer for 3 weeks to establish baseline activity. Movement data was collected continuously throughout the 12-week intervention, during which patients received electronically delivered, tailored, dynamic activity “prescriptions”, adjusted based on demonstrated individual capability, daily movement in their environment, and progress.

Results

Of 66 enrolled, 57 participants began and completed the intervention. The intervention resulted in significant improvements in average steps (+558 steps/day, p = 0.01), energetic capacity measured by power generation on a stationary bicycle (1.76 to 1.99 W/kg lean mass, p < 0.01), and quality of life (FACT-B TOI, 72.8 to 74.8, p = 0.02). The greatest improvement in functional energetic capacity was seen in the lowest performing tertile at baseline (0.76 to 1.12 W/kg, p < 0.01).

Discussion

Wearable technology delivery of personalized activity prescriptions based on individual capability and movement behaviors demonstrates feasibility and early effectiveness. The high variability seen in baseline activity and function, as well as in response to the intervention, supports the need for future work in precision approaches to physical activity (NCT03158519).

Abstract PS10-26: An initial safety study of gedatolisib plus cofetuzumab pelidotin for metastatic triple-negative breast cancer

Background: The PI3K pathway is dysregulated in the majority of triple-negative breast cancer (TNBCs), yet single agent inhibition of PI3K in TNBC has minimal clinical activity. We previously reported that PI3K inhibition leads to an immediate compensatory up-regulation of the Wnt pathway. Dual targeting of both pathways is highly synergistic against TNBC models in vitro and in vivo. We initiated a Phase I clinical trial of gedatolisib, a pan-class I isoform PI3K/mTOR inhibitor, and cofetuzumab pelidotin, an antibody-drug conjugate against the cell-surface PTK7 protein (Wnt pathway co-receptor) with an auristatin payload. PTK7 is up-regulated after PI3K inhibition and auristatin is in itself synergistic with gedatolisib providing the potential for a dual mechanism of synergy.

Methods: Dose escalation proceeded using a traditional 3+3 schema with a small expansion cohort at the final dose level to better characterize safety. Participants had metastatic TNBC or ER low (ER and PgR &lt;5%, HER2 negative) breast cancer, and had received at least one prior line of chemotherapy. The primary objective was safety. Secondary endpoints included objective response (ORR), clinical benefit at 18 weeks (CB18), and progression-free survival (PFS). Exploratory analyses probed the association of tumor DNA, RNA, and IHC with clinical efficacy to identify putative biomarkers.

Results: Between January 2018 and January 2020, 18 patients were enrolled in 3 dose cohorts: gedatolisib (qw) & cofetuzumab pelidotin (q3w) 110mg+1.4mg/kg (n=4), 180mg+1.4mg/kg (n=3), and 180mg+2.8mg/kg dose levels (n=11). The median age was 53 years (32-77). Nausea (n=16), anorexia (n=13), fatigue (n=12), and mucositis (n=12) were common but rarely reached &gt;Grade 3 severity (nausea, n=1; fatigue, n=2). Myelosuppression was uncommon (Grade &gt;3 neutropenia, n=2). 16 participants were evaluable for response. 3 achieved a confirmed partial response (PR), and 3 had stable disease (SD). ORR=18.8%. All 3 PRs lasted &gt; 6 months. CB18=31.3%. Median PFS was 2.0 months (95% CI for PFS:1.2-6.2); median OS was 9.5 months (95% CI for OS:4.3-not reached). Correlative analyses of genomic, transcriptomic, and protein biomarkers with response are currently ongoing.

Conclusions: The combination of gedatolisib + cofetuzumab pelidotin for the treatment of metastatic TNBC was found to be well tolerated and demonstrated promising clinical activity. Further investigation of this drug combination in metastatic TNBC is warranted.

Trial Registration: NCT03243331

Citation Format: Milan Radovich, Jeffrey P. Solzak, Bradley A. Hancock, Sunil Badve, Anna Maria V. Storniolo, Tarah J. Ballinger, Bryan P. Schneider, Kathy D. Miller. An initial safety study of gedatolisib plus cofetuzumab pelidotin for metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-26.

Impact of Body Mass Index on Presence of ctDNA and Disease Recurrence after Neoadjuvant Chemotherapy for Triple-Negative Breast Cancer: Analysis from BRE12-158

PURPOSE

This retrospective analysis aimed to determine the relationship between body mass index (BMI) and circulating tumor DNA (ctDNA) in triple-negative breast cancer (TNBC), and to evaluate the impact of BMI on disease recurrence and survival in the homogeneous, high-risk population of patients with residual TNBC after neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

BRE12-158 was a phase II trial of genomically directed therapy versus physician's choice in residual TNBC after chemotherapy. ctDNA was isolated from plasma samples, and categorized as positive or negative. BMI (kg/m²) after surgery was analyzed as both a continuous and categorical variable: normal weight, <25; overweight, 25-30; and obese, ≥30. We compared ctDNA category and BMI, and estimated probability of disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS) by BMI.

RESULTS

Of 177 patients in BRE12-158, 172 had BMI and 140 had ctDNA data. There was no difference in mean BMI between those with ctDNA positivity versus negativity (P = 0.48). There was no relationship between BMI category and presence of ctDNA (P = 0.31). In multivariate analysis, continuous BMI was not prognostic of DDFS (P = 0.996), DFS (P = 0.41), or OS (P = 0.98). There was no association between BMI categories and survival (P = 0.92, 0.74, and 0.97 for DDFS, DFS, and OS, respectively).

CONCLUSIONS

In patients with residual TNBC after neoadjuvant chemotherapy, BMI was not prognostic of DDFS, DFS, or OS. There was no signal of a relationship between BMI and presence of ctDNA. This suggests inherent aggressive tumor biology, in which host phenotype may have less influence and impact of weight loss interventions may be diminished.

Association of Circulating Tumor DNA and Circulating Tumor Cells After Neoadjuvant Chemotherapy With Disease Recurrence in Patients With Triple-Negative Breast Cancer: Preplanned Secondary Analysis of the BRE12-158 Randomized Clinical Trial

Importance

A significant proportion of patients with early-stage triple-negative breast cancer (TNBC) are treated with neoadjuvant chemotherapy. Sequencing of circulating tumor DNA (ctDNA) after surgery, along with enumeration of circulating tumor cells (CTCs), may be used to detect minimal residual disease and assess which patients may experience disease recurrence.

Objective

To determine whether the presence of ctDNA and CTCs after neoadjuvant chemotherapy in patients with early-stage TNBC is independently associated with recurrence and clinical outcomes.

Design, Setting, and Participants

A preplanned secondary analysis was conducted from March 26, 2014, to December 18, 2018, using data from 196 female patients in BRE12-158, a phase 2 multicenter randomized clinical trial that randomized patients with early-stage TNBC who had residual disease after neoadjuvant chemotherapy to receive postneoadjuvant genomically directed therapy vs treatment of physician choice. Patients had blood samples collected for ctDNA and CTCs at time of treatment assignment; ctDNA analysis with survival was performed for 142 patients, and CTC analysis with survival was performed for 123 patients. Median clinical follow-up was 17.2 months (range, 0.3-58.3 months).

Interventions

Circulating tumor DNA was sequenced using the FoundationACT or FoundationOneLiquid Assay, and CTCs were enumerated using an epithelial cell adhesion molecule-based, positive-selection microfluidic device.

Main Outcomes and Measures

Primary outcomes were distant disease-free survival (DDFS), disease-free survival (DFS), and overall survival (OS).

Results

Among 196 female patients (mean [SD] age, 49.6 [11.1] years), detection of ctDNA was significantly associated with inferior DDFS (median DDFS, 32.5 months vs not reached; hazard ratio [HR], 2.99; 95% CI, 1.38-6.48; P = .006). At 24 months, DDFS probability was 56% for ctDNA-positive patients compared with 81% for ctDNA-negative patients. Detection of ctDNA was similarly associated with inferior DFS (HR, 2.67; 95% CI, 1.28-5.57; P = .009) and inferior OS (HR, 4.16; 95% CI,1.66-10.42; P = .002). The combination of ctDNA and CTCs provided additional information for increased sensitivity and discriminatory capacity. Patients who were ctDNA positive and CTC positive had significantly inferior DDFS compared with those who were ctDNA negative and CTC negative (median DDFS, 32.5 months vs not reached; HR, 5.29; 95% CI, 1.50-18.62; P = .009). At 24 months, DDFS probability was 52% for patients who were ctDNA positive and CTC positive compared with 89% for those who were ctDNA negative and CTC negative. Similar trends were observed for DFS (HR, 3.15; 95% CI, 1.07-9.27; P = .04) and OS (HR, 8.60; 95% CI, 1.78-41.47; P = .007).

Conclusions and Relevance

In this preplanned secondary analysis of a randomized clinical trial, detection of ctDNA and CTCs in patients with early-stage TNBC after neoadjuvant chemotherapy was independently associated with disease recurrence, which represents an important stratification factor for future postneoadjuvant trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT02101385.

Abstract PO-172: Impact of African ancestry on the relationship between body mass index (BMI) and survival in early stage breast cancer: Retrospective analysis from E5103

Purpose: Both African American (AA) race and obesity are associated with worse survival in early stage breast cancer. Obesity disproportionately affects AA women, and may further racial disparities in breast cancer. Prior work investigating the intersection of race, BMI, and outcome in the large adjuvant trial E1199 found obesity to be prognostic of worse survival in White patients, with no significant impact on the disparately inferior survival outcomes seen in Black patients. However, this analysis was based on self-reported race, which neglects underlying genetic ancestry that may drive biologic differences. Here, we investigate the impact of BMI on outcomes in patients of African or European ancestry in the phase III adjuvant breast cancer trial E5103. Methods: E5103 enrolled patients with high risk, HER2 negative, early stage breast cancer to receive adjuvant doxorubicin and cyclophosphamide for 4 cycles, followed by 12 weeks of weekly paclitaxel, with or without bevacizumab. Genetic ancestry was determined on the 3,373 patients with available germline DNA, BMI, and outcome data using principal components from a genome-wide array. The primary objective was to assess the impact of BMI on disease free survival (DFS) and overall survival (OS) by ancestry. A univariate Cox proportional hazard model was used to evaluate the correlation between continuous or binary BMI and survival in AA or European Americans (EA). Results: 11.6% (n=390) of patients were genetically classified as AA and 74.6% (n=2517) as EA. Higher BMI (increment of every 5 kg/m2) was significantly associated with worse DFS (HR=1.24, p=0.006) and OS (HR=1.38, p=0.005) only in AAs, but not in EAs (DFS p=0.76, OS p=0.35). Exploring BMI categories in AAs, survival differences were most significant between patients who had morbid obesity (BMI ≥40) and those who did not (DFS HR= 2.01, p=0.009; OS HR=2.19, p=0.045). However, in EAs, even morbid obesity was not associated with survival (DFS p=0.89, OS p=0.31). In the ER+ sub-population, BMI was associated with both DFS (HR=1.29, p=0.032) and OS (HR=1.60, p=0.017) in AAs, but only with OS in EAs (HR=1.15, p=0.049). In the triple negative sub-population, there was a trend toward worse survival with increasing BMI in AAs (p=0.098), but not in EAs (p=0.62). Conclusion: In contrast to prior work based on self-reported race, we found BMI to be significantly associated with worse survival in women of African ancestry in E5103, a large adjuvant trial that reflects our current approach to curative systemic therapy in breast cancer. Categorically, this association was significant only for morbid obesity, suggesting the relationship between BMI, race, and outcome may depend on the degree of obesity. Genetic ancestry may explain biologic differences driving both higher BMI and worse outcomes resulting in racial disparities in breast cancer.

Citation Format: Tarah J. Ballinger, Guanglong Jiang, Fei Shen, Kathy D. Miller, Bryan P. Schneider. Impact of African ancestry on the relationship between body mass index (BMI) and survival in early stage breast cancer: Retrospective analysis from E5103 [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-172.

TBCRC 048: Phase II Study of Olaparib for Metastatic Breast Cancer and Mutations in Homologous Recombination-Related Genes

PURPOSE

Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi), is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) in germline (g)BRCA1/2 mutation carriers. Olaparib Expanded, an investigator-initiated, phase II study, assessed olaparib response in patients with MBC with somatic (s)BRCA1/2 mutations or g/s mutations in homologous recombination (HR)-related genes other than BRCA1/2.

METHODS

Eligible patients had MBC with measurable disease and germline mutations in non-BRCA1/2 HR-related genes (cohort 1) or somatic mutations in these genes or BRCA1/2 (cohort 2). Prior PARPi, platinum-refractory disease, or progression on more than two chemotherapy regimens (metastatic setting) was not allowed. Patients received olaparib 300 mg orally twice a day until progression. A single-arm, two-stage design was used. The primary endpoint was objective response rate (ORR); the null hypothesis (≤ 5% ORR) would be rejected within each cohort if there were four or more responses in 27 patients. Secondary endpoints included clinical benefit rate and progression-free survival (PFS).

RESULTS

Fifty-four patients enrolled. Seventy-six percent had estrogen receptor-positive HER2-negative disease. Eighty-seven percent had mutations in PALB2, sBRCA1/2, ATM, or CHEK2. In cohort 1, ORR was 33% (90% CI, 19% to 51%) and in cohort 2, 31% (90% CI, 15% to 49%). Confirmed responses were seen only with gPALB2 (ORR, 82%) and sBRCA1/2 (ORR, 50%) mutations. Median PFS was 13.3 months (90% CI, 12 months to not available/computable [NA]) for gPALB2 and 6.3 months (90% CI, 4.4 months to NA) for sBRCA1/2 mutation carriers. No responses were observed with ATM or CHEK2 mutations alone.

CONCLUSION

PARP inhibition is an effective treatment for patients with MBC and gPALB2 or sBRCA1/2 mutations, significantly expanding the population of patients with breast cancer likely to benefit from PARPi beyond gBRCA1/2 mutation carriers. These results emphasize the value of molecular characterization for treatment decisions in MBC.

Protocol of a randomized trial of acceptance and commitment therapy for fatigue interference in metastatic breast cancer

Fatigue interference with activities, mood, and cognition is one of the most prevalent and distressing concerns of metastatic breast cancer patients. To date, there are no evidence-based interventions for reducing fatigue interference in metastatic breast cancer and other advanced cancer populations. In pilot studies, Acceptance and Commitment Therapy (ACT) has shown potential for reducing symptom-related suffering in cancer patients. The current Phase II trial seeks to more definitively examine the efficacy of telephone-based ACT for women with metastatic breast cancer who are experiencing fatigue interference. In this trial, 250 women are randomly assigned to either the ACT intervention or an education/support control condition. Women in both conditions attend six weekly 50-min telephone sessions. The primary aim of this study is to test the effect of telephone-based ACT on fatigue interference. Secondary outcomes include sleep interference, engagement in daily activities, and quality of life. Outcomes are assessed at baseline, 2 weeks post-intervention, and 3 and 6 months post-intervention. This trial also examines whether increases in psychological flexibility, defined as full awareness of the present moment while persisting in behaviors aligned with personal values, account for the beneficial effect of ACT on fatigue interference. After demonstrating ACT's efficacy, the intervention can be widely disseminated to clinicians who care for metastatic breast cancer patients. Our findings will also inform future ACT trials with various cancer populations and functional outcomes.

Patient-reported outcomes in the Translational Breast Cancer Research Consortium

Members of the Translational Breast Cancer Research Consortium conducted an expert-driven literature review to identify a list of domains and to evaluate potential measures of these domains for inclusion in a list of preferred measures. Measures were included if they were easily available, free of charge, and had acceptable psychometrics based on published peer-reviewed analyses. A total of 22 domains and 52 measures were identified during the selection process. Taken together, these measures form a reliable and validated list of measurement tools that are easily available and used in multiple cancer trials to assess patient-reported outcomes in relevant patients.

Impact of primary breast cancer therapy on energetic capacity and body composition

Purpose

This observational study was designed to measure baseline energy parameters and body composition in early-stage breast cancer patients, and to follow changes during and after various modalities of treatment. This will provide information to aid in the development of individualized physical activity intervention strategies.

Methods

Patients with newly diagnosed stage 0–III breast cancer were enrolled into three cohorts: A (local therapy alone), B (endocrine therapy), or C (chemotherapy with or without endocrine therapy). At baseline, 6 months, and 12 months, subjects underwent a stationary bicycle protocol to assess power generation and DEXA to assess body composition.

Results

Eighty-three patients enrolled. Patients had low and variable levels of power generation at baseline (mean power per kilogram lean mass 1.55 W/kg, SD 0.88). Power normalized to lean body mass (W/kg) decreased significantly, and similarly, by 6 months in cohorts B (1.42–1.04 W/kg, p = 0.008) and C (1.53–1.18 W/kg, p < 0.001). In all cohorts, there was no recovery of power generation by 12 months. Cohort C lost lean body mass (− 1.5 kg, p = 0.007), while cohort B maintained lean body mass (− 0.2 kg, p = 0.68), despite a similar trajectory in loss of power. Seven patients developed sarcopenia during the study period, including four patients who did not receive any chemotherapy (cohort B).

Conclusions

The stationary bike protocol was feasible, easy, and acceptable to patients as a way to measure energetic capacity in a clinical setting. Early-stage breast cancer patients had low and variable levels of power generation, which worsened following primary therapy and did not show evidence of ‘spontaneous recovery’ by 12 months. Effective physical activity interventions will need to be personalized, accounting for both baseline ability and the effect of treatment.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4924-6) contains supplementary material, which is available to authorized users.

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