Abstract PD6-08: Analysis of immune infiltrates (assessed via multiplex fluorescence immunohistochemistry) and immune gene expression signatures as predictors of response to the checkpoint inhibitor pembrolizumab in the neoadjuvant I-SPY 2 trial

Background: Pembrolizumab (Pembro), an anti-PD-1 immune checkpoint inhibitor, has been approved for the treatment of a variety of cancers including melanoma, non-small cell lung cancer, head and neck squamous cell carcinoma, and urothelial carcinoma. Pembro was recently evaluated in HER2- breast cancer patients in the neoadjuvant I-SPY 2 TRIAL and graduated in the triple negative (TN), HR+HER2-, and HER2- signatures. HER2- patients were randomized to receive Pembro+paclitaxel followed by doxorubicin/cyclophosphamide (P+T -> AC) vs. T -> AC. We and others have shown that TN breast cancers tend to have high numbers of immune infiltrates, including T cells and tumor associated macrophages (TAMs). We evaluated expression signatures representing 14 immune cell types (TILs, T cells, CD8 T cells, exhausted T cells, Th1, Tregs, cytotoxic cells, NK, NK CD56dim, dendritic cells, mast cells, B cells, macrophages, and neutrophils) as specific predictors of response to Pembro.

Methods: Data from 248 patients (Pembro: 69; controls: 179) were available. Pre-treatment biopsies were assayed using Agilent gene expression arrays. Signature scores are calculated by averaging cell type specific genes. All I-SPY 2 qualifying biomarker analyses follow a pre-specified analysis plan. We used logistic modeling to assess biomarker performance. A biomarker is considered a specific predictor of Pembro response if it associates with response in the Pembro arm but not the control arm, and if the biomarker x treatment interaction is significant (likelihood ratio test, p<0.05). This analysis is also performed adjusting for HR status as covariates, and within receptor subsets. For successful biomarkers, we use Bayesian modeling to estimate the pCR rates of 'predicted sensitive' patients in each arm. Our statistics are descriptive rather than inferential and do not adjust for multiplicities of other biomarkers outside this study.

Results: 10 out of the 14 cell-type signatures tested are associated with response in the Pembro arm. Higher expression levels of 9 of these cell-type signatures are associated with higher pCR rates (T cells, exhausted T cells, Th1, cytotoxic cells, NK, NK CD56dim, dendritic cells, B cells, and macrophages), whereas higher mast cell signature expression is associated with non-pCR. Interestingly, many of these same signatures also associate or trend towards association with response in the control arm; and in a model adjusting for HR status, only 3 of these signatures (Th1, B cells and dendritic cells) show significant interaction with treatment. Within the whole population and the TN subtype, the dendritic cell signature is the strongest predictor of specific response to Pembro (OR/1SD: 4.04 and 4.4, LR p < 0.001 overall and in TN). Although other immune signatures (T cells, exhausted T cells, NK, and macrophages) also associate with response in the Pembro arm in the TN subtype, only the dendritic cell and Th1 signatures have a significant interaction with treatment. In contrast, in the HR+HER2- subtype, only 3 signatures (Th1, B cells, and mast cells) associate with response to Pembro; but none of these signatures have significant interaction with treatment. Of note, in both the Pembro and control arms, HR+HER2- patients with higher average mast cell marker expression have lower pCR rates (OR/1SD: 0.33 and 0.51, LRp: 0.006 and 0.04 in Pembro and control arm).

Conclusion: As expected, multiple immune cell expression signatures are predictive of response in the Pembro arm; but only dendritic cells and Th1 cells are specific to Pembro in both the population as a whole and the TN subtype. Interestingly, the presence of mast cells may impede response, especially in HR+HER2- patients. Correlation of these signatures with multiplex-IF immune markers is pending.

Citation Format: Campbell M, Yau C, Borowsky A, Vandenberg S, Wolf D, Rimm D, Nanda R, Liu M, Brown-Swigart L, Hirst G, Asare S, van't Veer L, Yee D, DeMichele A, Berry D, Esserman L. Analysis of immune infiltrates (assessed via multiplex fluorescence immunohistochemistry) and immune gene expression signatures as predictors of response to the checkpoint inhibitor pembrolizumab in the neoadjuvant I-SPY 2 trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-08.

Abstract PD2-14: Participation in a personalized breast cancer screening trial does not increase anxiety at baseline

Introduction: The purpose of this study is to examine whether participation in a personalized screening trial is associated with anxiety or breast cancer worry. The Patient Centered Outcomes Research Institute recently funded WISDOM (Women Informed to Screen Depending On Measures of risk), which is a randomized trial that tests the safety and efficacy of basing starting age, stopping age, frequency and modality of breast cancer screening on individual risk (Clinical Trials Identifier NCT02620852).

Methods: In WISDOM, participants can be randomized to annual screening or personalized screening arm, or self-select an arm an observational cohort. This interim analysis examined the first 1817 participants to determine if the personalized risk arm is acceptable and to explore whether baseline anxiety was associated with study arm. For acceptability our target was to have >60% of participants agree to randomization. Participants completed questions about their Risk Perception, the PROMIS Anxiety short form 8a (total scores 8-40 with higher scores indicating more anxiety), and Breast Cancer Risk Worry (BCRW) survey (total scores 5-20) with higher scores indicating more worry) at baseline and before they were given information on their personal risk or study assignment. For the purposes of these analyses, we defined high anxiety to be the percentage of participants scoring =>22 on the PROMIS and >8 on the BCRW.

Results: The participants were recruited from three sites (UCSD, UCSF, Sanford Health). Of the 1817 initial participants, 1643 completed the baseline questionnaire. Participants has a mean age of 57 years (SD 9). 15.8% felt their chances of developing breast cancer was high, 19.5% felt their chance of developing breast cancer was greater than the average women, and 56.6% felt their lifetime risk of developing breast cancer was >25. Risk perception was not significantly different between women who opted to be randomized versus the observational arm.

The majority of participants were willing to be randomly assigned to an arm (1071/1643, 65.1%). Of those who joined the observational cohort, the majority selected personalized risk arm (474/572, 82.9%). Overall, PROMIS anxiety scores were low at baseline (14.0 MEAN (SD 4.6)) as were the Breast Cancer Risk Worry scores (5.7 MEAN (SD 1.05)). Less than 8% of participants had PROMIS scores >22 and that did not vary across the randomized or observational groups (P=0.2)). About 2% of participants had a BCRW scores >8. Women who worried with breast cancer were more likely to select to be in the observational (3.5%) than randomized (1.7%) arm of the study (P=0.02).

Conclusions: For the women approached to participate in Wisdom, personalized screening was acceptable alternative to annual mammography. Participants in general overestimated their lifetime risk of breast cancer, had very low anxiety and low breast cancer worry. Those who were worried about breast cancer opted more often for the observational arm of the study to allow them to choose between the personalized versus annual arm. Future analyses will follow participants prospectively to determine adherence to assigned or selected arm, and whether anxiety changes after receipt of their personalized risk information.

Citation Format: Naeim A, Sepucha K, Wenger N, Eklund M, Annette S, Madlensky L, van't Veer L, Parker B, Yau C, Cink T, Anton-Culver H, Borowsky A, Petruse A, Sarrafan S, Stover-Fiscalini A, LaCroix A, Adduci K, Wisdom Advocate Partners, Laura E. Participation in a personalized breast cancer screening trial does not increase anxiety at baseline [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD2-14.

Abstract OT3-03-01: Preference-Tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study in progress

Purpose: Women Informed to Screen Depending on Measures of risk (WISDOM) trial is a pragmatic study comparing two real world approaches to clinical care for breast screening: annual screening versus personalized screening. The novelty of the personalized arm of the study is that we are combining known risk factors (age, family history, history of breast disease, ethnicity, BIRADS breast density, and genetics) into a single risk assessment model. All components of the model have been tested and established, but have never been used jointly.

The goal of the WISDOM study is to examine the effectiveness of personalized breast cancer screening and to bring objective recommendations to the current mammography screening debate.

Methods: The WISDOM trial will enroll 100,000 women with a preference-tolerant design that will determine if risk-based screening vs. annual screening, is as safe, less morbid, enables prevention, and is preferred by women. Women 40 - 74 years of age with no history of breast cancer or DCIS, and no previous double mastectomy can join the study from the WISDOM Study website (wisdomstudy.org). All participants sign up, elect randomization or self-select the study arm, provide electronic consent using DocuSign (eConsent), and sign a Medical Release Form. For all participants, 5-year risk of developing breast cancer is calculated according to the Breast Cancer Screening Consortium (BCSC) model. For participants in the personalized arm, the overall 5-year risk BCSC score is combined with a Polygenic Risk Score, based on a genetic test including mutations in 9 genes (BRCA1, BRCA2, TP53, PTEN, STK11, CDH1, ATM, PALB2, and CHEK2) and a panel of 75 common single nucleotide polymorphisms known to increase breast cancer risk. Risk stratification will determine frequency of screening. The study is registered on ClinicalTrials.gov as NCT02620852.

Results: As of June 12th 2017, the WISDOM study is live at all UC medical centers and recruitment is open to all eligible women in California. Up to date 4,769 eligible women registered at all sites. 2,823 women have consented in the trial. 64% were randomized and 36% chose their screening arm. A pilot was conducted to test the logistics of online participation and examine the acceptance of the study design and approach. We are partnering with health insurance companies and self-insured companies to reach our recruitment goal.

Conclusions: Enrollment will be completed by end of 2018.

Acknowledgment: support by the Patient-Centered Outcomes Research Institute (PCORI), PCS-1402-10749 to L.J.E.

(*) Authors equally contributed to this work.

Citation Format: Acerbi I, Abihider K, Ling J, Layton T, DeRosa D, Madlensky L, Tice J, Shieh Y, Ziv E, Sarrafan S, Firouzian R, Tong B, Blanco A, Lee V, Heditsian D, Brain S, Kaplan C, Borowsky A, Anton-Culver H, Naeim A, Cink T, Stover Fiscalini A, Parker B, van 't Veer L, Wisdom Study and Athena Breast Health Network Investigators and Advocate Partners, LaCroix A, Esserman L. Preference-Tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study in progress [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-03-01.

Abstract P3-09-02: Risk stratification using clinical risk factors and genetic variants in a personalized screening trial

Introduction: Tailoring breast cancer screening according to individual risk may represent an improvement over the current practice of age-based screening. WISDOM (Women Informed to Screen Depending on Measures of Risk) is an ongoing randomized trial comparing the safety, efficacy, cost, and patient acceptability of personalized versus annual screening. Women in the personalized arm receive screening recommendations based on sequencing of 9 genes associated with hereditary breast cancer and a 5-year risk estimate from the Breast Cancer Surveillance Consortium (BCSC) risk model modified by a polygenic risk score (PRS) comprised of 75 single nucleotide polymorphisms. WISDOM represents the first-ever use of a PRS to prospectively modify risk estimates and allows comparison of risk model performance in a population-based setting. Thus, we evaluated the risk estimates generated by: 1) the Breast Cancer Risk Assessment Tool (BCRAT) based on the Gail model, 2) the BCSC model, and 3) the BCSC model modified by the PRS (BCSC-PRS).

Methods: We analyzed participants in the personalized screening arm of the WISDOM Study (NCT02620852). The trial opened in October 2016 and is enrolling participants aged 40-74 years. Participants' self-reported demographic and risk factor information were collected through an online portal. Genotyping of participants in the personalized arm was done using a custom panel from Color Genomics. 5-year risk estimates were generated using the BCRAT (2011 version), BCSC, and BCSC-PRS models. In the latter, the PRS was used as a Bayesian likelihood ratio to modify the BCSC 5-year risk estimate. We compared the distributions of BCRAT, BCSC, and BCSC-PRS risk estimates around a low-risk (<1%) and moderately high-risk (≥3%) threshold using a paired statistical test (McNemar).

Results: To date, WISDOM has enrolled 2,065 participants, of whom 1,157 are in the personalized arm and 830 have completed risk assessment. The median age was 57 years (interquartile range, IQR 49-64). 83% were Caucasian, 2% African-American, and 7% Asian. 8% self-reported as Hispanic. The median 5-year risk was 1.7% (IQR 1.1-2.3%) using the BCRAT, 1.6% (IQR 1.1-2.3%) using the BCSC model, and 1.5% (IQR 0.9-2.7%) using the BCSC-PRS model. The BCSC-PRS model classified more women into the low (<1%) and moderately high (≥3%) risk categories compared with the BCRAT (p < 0.001) and BCSC model (p < 0.001), Table.

5-year risk classification according to the BCRAT, BCSC and BCSC-PRS models <1%1-3%≥3% n (%)n (%)n (%)Gail161 (19)556 (67)113 (14)BCSC159 (19)568 (68)103 (12)BCSC-PRS275 (33)379 (46)176 (21)

Discussion: Adding a PRS to the BCSC model categorized significantly more women below the low-risk threshold and above the moderately high-risk threshold compared with the BCSC model and BCRAT. Furthermore, the BCSC and BCRAT generated similar distributions of risk estimates. Follow-up with incident breast cancer data is needed to determine whether the reclassification provided by the PRS improves risk stratification and clinical outcomes. However, our preliminary findings suggest that incorporating genetic variants into a validated clinical model is feasible and could enhance risk prediction.

Citation Format: Shieh Y, Ziv E, Eklund M, Sabacan L, Firouzian R, Madlensky L, Anton-Culver H, Borowsky A, LaCroix A, Naeim A, Parker B, van't Veer L, Esserman L, Tice J, WISDOM Study and Athena Network Investigators WS. Risk stratification using clinical risk factors and genetic variants in a personalized screening trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-09-02.

Abstract P5-02-03: Evaluating the feasibility of a web-based preference-tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study pilot

Background: The WISDOM Study (Women Informed to Screen Depending on Measures of risk) aims to examine the effectiveness of personalized breast cancer screening and to bring objective recommendations to the current mammography screening debate. The WISDOM Study is a 100,000 woman randomized trial with a preference-tolerant design that will determine if risk-based screening (RBS) vs. annual screening, is as safe, less morbid, enables prevention and is preferred by women. A pilot was conducted to test the logistics of online participation and examine the acceptance of the study design and approach.

Methods: Women were recruited from the UCSF site of the Athena Breast Health Network, a clinical care-research cohort of 110,000 women from the 5 University of California Medical Centers and Sanford Health. The pilot recruited women via email who were 40 -74 years of age with no history of breast cancer and a normal mammogram in the past year. Those interested visited the WISDOM Study website (wisdomstudy.org), signed up, elected randomization or self-selection, provided electronic consent using DocuSign (eConsent), and completed genetic testing (RBS arm). The Breast Cancer Surveillance Consortium (BCSC) model (standard risk factors, ethnicity, and breast density) in addition to genetic testing (9 genes and 75 SNPs) was used to calculate breast cancer risks that informed the start and frequency of screening for women in the RBS arm. BCSC was also used in the annual screening arm but did not inform mammography screening recommendations. The pilot used a mixed method approach (using enrollment data, Exit Survey data, individual interviews and focus groups) to assess enrollment preferences, randomization acceptance and overall study workflow.

Results: The online electronic enrollment process and patient engagement portal was successfully implemented. In total, 639 women were invited, 235 registered (34%), and 171 (27%) consented to the pilot. Of these, 74% (127) elected to be randomized, and 26% chose to self-assign (66% chose annual screening (29)). Mean age was 56 years and the ethnic breakdown of the cohort was: 79% White, 10% Asian, 7% Latino, 3% Black, 1% other. 92% of those in the risk-based arm of the study completed genetic testing and were given results; only one genetic mutation was identified and occurred in CHEK2. Within the RBS arm (78), mammography recommendations were: 61% no further mammography until the age of 50, 22% biennial, 11% annual, and 6% every 6 month alternating MRI and mammogram. Exit Survey data illuminated confusion in study arm names (risk-based vs. annual), randomization acceptance (74%), annual arm preference in the self-selection group (66%), eConsent satisfaction (90%), enrollment process ease of use (88%), and website content, navigation and appearance satisfaction (66%). The pilot concluded in May 2016 to allow for refinements prior to the full trial.

Conclusion: Our pilot demonstrates that the majority of women are willing to be randomized and participate in an online screening study to answer the important question on optimal breast cancer screening. The pilot study results will inform implementation of the 100,000 women WISDOM Study which launches in fall of 2016.

Citation Format: Stover Fiscalini A, Theiner S, Kaplan C, Sarrafan S, Sawyer S, Liang A, Rosenberg-Wohl S, Gordon D, Frick M, Borowsky A, Anton-Culver H, Naeim A, LaCroix A, Cink T, Collaboration Athena Breast Health Network and Advocate Partners, Esserman L, van 't Veer L. Evaluating the feasibility of a web-based preference-tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study pilot [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-02-03.

Abstract P3-10-01: A pilot feasibility study of the WISDOM study, a preference-tolerant randomized controlled trial evaluating a risk-based breast cancer screening strategy

Background: For almost 30 years, annual mammograms for women over 40 have been a cornerstone of the US strategy to reduce breast cancer mortality. Introduction of the 2009 USPSTF screening guidelines, though based on a thorough review of the scientific literature, has triggered scientific debate and a stalemate. The solution is not to prolong the controversy with repetitious reviews of past studies, but rather to test and implement a personalized model that leverages advances in breast cancer biology, risk assessment, and imaging to provide screening recommendations based upon well-characterized measures of risk. Our WISDOM (Women Informed to Screen Depending On Measures of risk) study, a preference-tolerant randomized controlled trial funded through PCORI, will evaluate whether such a risk-based screening strategy, compared to annual screening, is as safe, is less morbid, enables prevention and is preferred by women. This upcoming pilot study will test the feasibility and technical implementation of the WISDOM trial, focusing on recruitment, enrollment, and randomization processes, a coverage with evidence development approach to enable rapid adoption, and patient experience and satisfaction. Findings will directly inform implementation of the full trial, slated to begin in fall 2015 throughout the Athena Breast Health Network, a research and care collaboration across the five UC Medical Centers and Sanford Health.

Trial Design: 225 participants will be recruited from Athena patients receiving care at UCSF. Participants must be female; between age 40 and 75; have had a normal mammogram at UCSF in the past 6 months; and in the Athena research cohort. Exclusion criteria are a breast cancer or DCIS diagnosis; inability to provide consent; or inability to speak English. After education about the trial, patients will be asked if they are willing to be randomized to either the risk-based or annual screening schedule; if not, they can self-assign to their preferred schedule. The randomized and self-assigned cohorts will receive the same interventions. The risk-based screening strategy will incorporate risk assessment based on the latest Breast Cancer Surveillance Consortium model along with established and recently validated genetic risk factors, co-morbidities, and breast density, and will be used to tailor individual recommendations for starting and stopping age, frequency, and screening modality. A saliva assay will be administered to participants in the risk-based arm to screen for genetic breast cancer risk factors (BRCA1 & BRCA2 + 9 additional genes + 81 single nucleotide polymorphisms).

Statistical Methods: Descriptive statistics for the proportion of women who are willing to be randomized, choose the risk-based arm in the self-assigned cohort, and are willing to accept their assigned or chosen screening schedule, as well as the distribution of participant anxiety scores, will be analyzed. This will inform statistical design for the full trial, including the number of women who should be approached to enroll 65,000 randomized participants and the sample size needed to measure anxiety and decision regret in the randomized cohort. Results from the pilot will be available September 30, 2015.

Citation Format: Narasimmaraj PR, Stover Fiscalini A, Kaplan CP, van't Veer LJ, Hallada AM, Thompson CK, Theiner S, Borowsky A, Naeim A, Anton-Culver H, LaCroix A, Athena Breast Health Network Investigators, Esserman LJ. A pilot feasibility study of the WISDOM study, a preference-tolerant randomized controlled trial evaluating a risk-based breast cancer screening strategy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-10-01.

Metaplastic breast tumors with a dominant fibromatosis-like phenotype have a high risk of local recurrence

BACKGROUND

In the current study the authors describe the clinicopathologic characteristics of a low grade variant of spindle cell metaplastic tumors of the breast. Previously these tumors have been considered within a larger group recognized as metaplastic carcinoma, including cases with higher grade features.

METHODS

Breast tumors comprised predominantly of low grade spindle cells, with sparse low grade epithelial elements, were selected. Clinical features as well as macroscopic, microscopic, and immunohistochemical findings were reviewed with emphasis on the biologic behavior and the differential diagnosis from other spindle cell lesions.

RESULTS

Of 30 tumors fulfilling strict criteria, 20 contained squamous or glandular elements associated with the spindle cells. Ten tumors were comprised entirely of low grade spindle cells with limited clustered epithelioid cells. At the periphery, all tumors showed a proliferation of bland spindle cells infiltrating the adjacent parenchyma and mimicking fibromatosis. The epithelioid cells and some spindle cells expressed both vimentin and one or more cytokeratins. Seven of eight patients treated by excisional biopsy developed local recurrence, whereas only one of ten patients treated with wide excisional biopsy developed a local recurrence. No distant or regional metastases occurred.

CONCLUSIONS

The presence of limited clusters of epithelioid cells along with a dominant fibromatosis-like pattern may be unique in the breast. The biologic potential of the fibromatosis-like, spindle cell, metaplastic breast tumors most likely is defined by their major histologic phenotype; they are capable of local recurrence with no demonstrated distant spread or regional metastases, as in pure fibromatosis of the breast.

Volvulus due to a tumor of Meckel's diverticulum

Small-bowel obstruction in an old woman was the result of a twisted Meckel's diverticulum containing a large neoplasm. As neoplasms comprise only 1.2-1.4% of the complications of the diverticulum, and generally bleed or cause intussusception, we believe that the condition described is not common.