Clinical outcomes after 1 versus 2-3 lines of neoadjuvant therapy in stage III inflammatory breast cancer

PURPOSE

Many stage III inflammatory breast cancer (IBC) patients experience a sufficient response to first-line (1L) neoadjuvant chemotherapy (NAC) to allow surgery, while some require additional NAC. We evaluated the pathologic complete response (pCR), breast cancer-free survival (BCFS) and overall survival (OS) among patients requiring 1 vs. 2-3 lines (L) of NAC prior to surgery.

METHODS

Stage III IBC patients from 2 institutions who received 1L or 2-3L of NAC prior to surgery were identified. Hormone receptor and HER2 status, grade, and pCR were evaluated. BCFS and OS were evaluated by the Kaplan-Meier method. Multivariable Cox models were utilized to estimate the hazard ratio (HR).

RESULTS

808 eligible patients (1997-2020) were identified (median age 51 years, median follow-up 69 months). 733 (91%) had 1L and 75 (9%) had 2-3L of NAC. Grade III, triple-negative and HER2-positive disease were more prevalent in 2-3L patients. 178 (24%) 1L and 14 (19%) 2-3L patients had pCR. 376 1L patients and 41 2-3L patients had recurrences. The 5-year BCFS was worse for the 2-3L group (33 vs. 46%, HR = 1.37; 95% CI 0.99-1.91). However, in 192 patients with a pCR, BCFS was similar (76 vs. 83% in 1L vs. 2-3L, respectively). There were 308 deaths (276 among 1L and 32 among 2-3L patients). The 5-year OS in 1L vs. 2-3L was 60 vs. 53% (HR = 1.32, 95% CI 0.91-1.93).

CONCLUSIONS

Among stage III IBC patients, pCR rates were similar, irrespective of the NAC lines number, and BCFS and OS were comparable with pCR after 1L and 2-3L.

Reassessing Estrogen Receptor Expression Thresholds for Breast Cancer Prognosis in HER2-negative Patients Using Shape Restricted Modeling

Purpose

To assess the dynamic link between continuous estrogen receptor (ER) expression and long-term clinical outcomes in non-metastatic breast cancer and to identify the ideal cutoff value for ER expression to optimize endocrine therapy use.

Methods

The study included 3055 female patients with stage II or III HER2-negative breast cancer. The primary outcomes were time to recurrence or death (TTR) and overall survival (OS). We used a novel shape-restricted Cox model to determine the desirable ER expression cutoff to predict breast cancer prognoses. Our novel model allows ER as a continuous variable, utilizing a flexible monotone-shaped Cox regression to assess its association with survival outcomes holistically.

Results

The shape-restricted Cox model identified 10% ER as the preferred cutoff to predict TTR. The finding was confirmed by the log-rank test and standard Cox model that patients with ER ≥ 10% had TTR benefit over ER < 10% (log-rank p < 0.001). No OS or TTR benefit of adjuvant endocrine therapy was observed in patients with 1% ≤ ER < 10% (HR 0.877, 95% CI 0.481-1.600, p = 0.668 for TTR and HR 0.698, 95% CI 0.337-1.446, p = 0.333 for OS).

Conclusions

Using the shape-restricted Cox model, this study suggests a potential preferred threshold of 10% for predicting TTR. The findings could assist physicians in effectively weighing the benefits and risks of adjuvant endocrine therapy for patients with ER < 10% disease, particularly in cases involving severe adverse events. Further prospective studies are warranted to validate the recommended cutoff value.

Inflammatory breast cancer biomarker identification by simultaneous TGIRT-seq profiling of coding and non-coding RNAs in tumors and blood

Inflammatory breast cancer (IBC) is the most aggressive and lethal breast cancer subtype, but lags in biomarker identification. Here, we used an improved Thermostable Group II Intron Reverse Transcriptase RNA sequencing (TGIRT-seq) method to simultaneously profile coding and non-coding RNAs from tumors, PBMCs, and plasma of IBC and non-IBC patients and healthy donors. Besides RNAs from known IBC-relevant genes, we identified hundreds of other overexpressed coding and non-coding RNAs (p≤0.001) in IBC tumors and PBMCs, including higher proportions with elevated intron-exon depth ratios (IDRs), likely reflecting enhanced transcription resulting in accumulation of intronic RNAs. As a consequence, differentially represented protein-coding gene RNAs in IBC plasma were largely intron RNA fragments, whereas those in healthy donor and non-IBC plasma were largely fragmented mRNAs. Potential IBC biomarkers in plasma included T-cell receptor pre-mRNA fragments traced to IBC tumors and PBMCs; intron RNA fragments correlated with high IDR genes; and LINE-1 and other retroelement RNAs that we found globally up-regulated in IBC and preferentially enriched in plasma. Our findings provide new insights into IBC and demonstrate advantages of broadly analyzing transcriptomes for biomarker identification. The RNA-seq and data analysis methods developed for this study may be broadly applicable to other diseases.

Abstract P5-06-06: TROP2 and HER2 expression by liquid biopsy in women with mTNBC

Introduction A blood-based biopsy can inform the prognosis for MBC patients when conventional tissue biopsies are not feasible within often biologically heterogeneous sites of metastatic disease. Several anti-Trophoblast cell-surface antigen 2 (TROP2) and HER2 targeted therapies are now available, either as approved therapy options or in clinical trials for MBC patients. Tumor expression of TROP2 is prominent in metastatic cancers, such as HER2-negative MBC and TNBC, with limited treatment options. Technical feasibility data of blood-based TROP2 and HER2 immunofluorescence assays demonstrate the utility of the Epic Sciences platform for this cohort of metastatic TNBC (mTNBC) patients. Methods Cultured cancer cells (expressing TROP2, HER2, or neither) were added to Healthy Donor (HD) blood, creating the model system used in assay development studies. Blood from 11 confirmed mTNBC patients was collected to analyze this clinically relevant population. Immunofluorescence staining and image analysis were performed on replicate blood-based biopsy slides to assess expression for TROP2 and HER2. CTCs were identified and characterized using Epic Sciences digital imaging and machine learning algorithms. Results Three cancer cell lines of various TROP2 expression levels (HEK293, low; MDA-MB-231, intermediate; and A431, high) exhibited immunofluorescence signal ranges of 168 MFI, 2147 MFI, and 26982 MFI, respectively. A fluorescence cutoff of 218 MFI was established following assay optimization to distinguish TROP2 positive CTCs based on a 95% confidence level. Within the cohort of 11 mTNBC patients, 100% of patients with mTNBC had detectable CTCs. 64% of mTNBC patients had TROP2 positivity (MFI, mean: 1328, range: 37-38281)). On the other hand, 0% of mTNBC patients had HER2 positivity (MFI, mean: 128, range: 40-361)). To date, studies with biomarker expression for these two drugs have been limited to tissue biopsy, which may not always yield contemporaneous sampling in the metastatic setting. These results offer a potential liquid biopsy test identifying pts more responsive to trop2 and her2 directed therapies. Discussion Here we report on a liquid biopsy profile combining protein expression of TROP2 and HER2. Blood-based assessment of TROP2 and HER2 expression is a potential marker for selecting MBC patients likely to respond to anti-TROP2 targeted therapies such as Sacituzumab, or Trastuzumab Deruxtecan has shown to improve survival in mTNBC in the ASCENT trial and DESTINY-04 studies. Recent data on the Destiny-04 trial, which allocated HER2 expressing MBC patients into T-DXd treatment, transformed the definition of TNBC. The development of quantitative, reproducible, and more sensitive immunofluorescence assays is becoming crucial for assigning patients whose disease continually evolves to targeted therapies by increasing clinical trial options. Analysis of the clinical utility of the blood-based cell analysis in guiding patient selection strategies for novel anti-TROP2, HER2, and other targeted therapies treatment in MBC is ongoing.

Citation Format: David Bourdon, Alessandra Cunsolo, Brandon Guillory, Megan M. Slade, Giuseppe Di Caro, Alisa Tubbs, Toshiaki Iwase, Naoto T. Ueno. TROP2 and HER2 expression by liquid biopsy in women with mTNBC [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 P5-06-06.

Abstract P3-02-04: Phase II study of Pembrolizumab Maintenance treatment in patients with HER2-negative inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC) after response to chemotherapy

Accumulating physical and hematologic toxicities make the indefinite use of chemotherapy unfeasible for many patients with metastatic/recurrent HER2– IBC or TNBC. Whether maintenance immunotherapy has a role in the treatment of these patients is unclear. We conducted a single-arm phase II trial of pembrolizumab monotherapy in patients with metastatic/recurrent HER2– IBC or TNBC (regardless of their PD-L1 expression status) and report here the clinical data from this trial. Methods: Eligible patients were enrolled between 2015 and 2022 and had had a CR, a PR, or SD after a minimum of 3 cycles of chemotherapy for metastatic/recurrent disease. PD-L1 expression status was not used to determine eligibility. Patients received 200 mg of pembrolizumab every 3 weeks (q3w) until disease progression, intolerable toxicity, or 2 years. In late 2021, the study was amended to allow patients who had received ≥8 cycles of q3w therapy to transition to q6w dosing (400 mg), based on the FDA’s approval of both dosing regimens across all indications. The primary endpoint was the 4-month disease control rate (DCR); exploratory endpoints included safety and correlative biomarkers from tissue and blood to ascertain associations between clinical response and PD-L1 expression, T-cell clonality, and immune profiling. Results: Of 43 patients (median age, 54 years; range, 34-77 years), 11 had IBC (10 with triple-negative IBC and 1 with ER+ HER2– IBC), and 32 had TNBC. The 4-month DCR was 58.1% (95% CI: 43.4%-72.9%). During a median follow-up of 11.4 months, 25 patients died. The entire cohort’s median OS and PFS times were 26.0 months (95% CI: 11.0-33.5 months) and 4.8 months (95% CI: 3.0-7.1 months), respectively. The median OS times of the IBC and TNBC groups did not differ significantly, nor did those of the CR, PR, and SD groups. The median PFS times of the IBC group (2.2 months) and TNBC group (4.8 months) did not differ significantly (p = .12), but those of the CR, PR, and SD groups did (not reached, 10.3 months, and 3.4 months, respectively; p = .01). Among the 37 patients who are off study treatment, most patients (84%; n=31/37) discontinued treatment owing to disease progression rather than toxicities (n=2), and the toxicities overall were consistent with the known profile of single-agent anti-PD1. Five patients had grade 3 events; there were no grade 4 or 5 events. Three patients had irreversible endocrinopathies (thyroiditis and adrenal insufficiency) requiring hormone replacement, but only 1 patient discontinued pembrolizumab because of these events. One patient discontinued treatment because of optic neuritis requiring steroids. Four patients completed 2 years of treatment without disease progression. Conclusions: Pembrolizumab maintenance therapy achieves acceptable disease control after induction chemotherapy. The PFS in this trial compares favorably to the expected durations of response to later lines of therapy. The toxicity profile of pembrolizumab compares favorably with those of chemotherapy and ADCs, which may provide a rationale for the use of ICIs in this setting. However, whether pembrolizumab maintenance therapy is helpful in TNBC patients who have received concurrent pembrolizumab with neoadjuvant chemotherapy is unknown, as these patients were excluded from the trial. Acknowledgements: This trial was supported by Merck.

Citation Format: Toshiaki Iwase, Angela Alexander, Vivian Chiv, Megumi Kai, Kumiko Kida, Charla Parker, Angela N. Marx, Evan Cohen, Hui Gao, James Reuben, Xiaoping Wang, Savitri Krishnamurthy, Diane Liu, Yu Shen, David Ramirez, Debu Tripathy, Daniel Booser, Clinton Yam, Vicente Valero, Bora Lim, Naoto T. Ueno, Jie S. Willey. Phase II study of Pembrolizumab Maintenance treatment in patients with HER2-negative inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC) after response to chemotherapy [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 P3-02-04.

Abstract P4-02-26: Quantitative estrogen receptor expression affects pathologic complete response to neoadjuvant chemotherapy in patients with early-stage breast cancer with low expression of HER2

BACKGROUND Recent pooled analysis of four major clinical trials of neoadjuvant chemotherapy (NAC) indicated that tumors with low expression of HER2 (HER2-low) as defined by immunohistochemistry (IHC) could be a new subgroup of breast cancer, distinct from HER2-negative tumors. In estrogen receptor (ER)-positive/HER2-negative breast cancer, we previously reported that 9.5% ER expression by IHC was the most appropriate cutoff to predict survival outcomes. However, little is known about the effect of quantitative ER expression on NAC outcomes in patients with HER2-low breast cancer. The present study aimed to elucidate the role of quantitative ER expression as a predictive and prognostic biomarker in the newly established HER2-low subgroup. MATERIALS AND METHODS We retrospectively reviewed the charts of 2,016 patients with newly diagnosed ER- and/or progesterone receptor (PR)-positive breast cancer between January 1982 and January 2019 in an extensive clinical database at The University of Texas MD Anderson Cancer Center. Our analysis included patients whose ER%, PR%, and HER2 IHC (0 to 2+) data were available. HER2-low was defined as IHC 1+ and 2+/situ hybridization (ISH)-negative. All patients had stage II or III disease at presentation and received NAC with anthracycline and a taxane-based combination regimen. Those with ER-positive tumors also received adjuvant endocrine therapy. The primary outcome measure was pathologic complete response (pCR) rate, compared between groups using logistic regression. Secondary outcomes were progression-free survival and overall survival after NAC completion, compared using Kaplan-Meier analysis and the log-rank test. The cutoff value for ER and PR positivity was 10% in the main analysis, identified by recursive partitioning and regression trees. RESULTS Among the 2,016 patients, 1134 (56%) had cStage II and 882 (44%) had cStage III disease. For IHC HER2 levels, 739 patients had 0 (37%), 926 had 1+ (46%), and 351 had 2+ (17%). For the primary outcome, 123 patients (6%) achieved pCR. The median follow-up period was 6.78 years. During the follow-up, 571 (28%) had distant metastasis. Mean ER expression (%) increased with HER2 IHC (HER2 IHC 0: 74.2%, 1+: 76.7%, 2+: 78.2%). In the multivariate logistic model, ER-negative (p&lt; 0.0001), PR-negative (p &lt; 0.0001), and high nuclear grade (p&lt; 0.05) disease were associated with higher pCR rates. Although pCR rate did not differ among HER2 IHC groups (0 = 6.09%, 1+ = 6.26%, 2+ = 5.7%; p=0.93), significantly higher pCR rates were observed in the HER2 IHC=0/1+ and 1%≤ER&lt; 10% group (p=0.0013) than in the HER2 IHC=0/1+ and ER≥10%, and HER2 IHC=2+ and ER≥10% groups. Kaplan-Meier curves showed that patients in the ER≥10% group had marginally improved PFS (p=0.046) and significantly longer OS (p=0.004) regardless of HER2 IHC status. Multivariable analysis showed that HER IHC status did not affect survival outcomes. Exploratory analysis showed that the patients with 70% or less in ER expression and HER2 IHC 1+/2+ tumor had higher pCR rate (12.3%) compared to those with ER&gt;70% (4.1%). CONCLUSIONS Patients with ≥10% ER expression had better survival outcomes than those with ER&lt; 10% regardless of HER2 expression level. The degree of HER2 expression in the HER2-low subgroup was not an independent predictive and prognostic factor for NAC response. The cutoff for ER expression for its predictive effect on pCR needs further validation in large external datasets.

Citation Format: Toshiaki Iwase, Takeo Fujii, Clinton Yam, Wenli Dong, Yu Shen, Debu Tripathy, Naoto T. Ueno. Quantitative estrogen receptor expression affects pathologic complete response to neoadjuvant chemotherapy in patients with early-stage breast cancer with low expression of HER2 [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 P4-02-26.

Abstract P4-07-14: Long-term Outcomes After 1 or 2-3 Lines of Neoadjuvant Therapy in Stage III Inflammatory Breast Cancer

Background: Inflammatory breast cancer (IBC) is associated with a poor prognosis. While many stage III IBC patients (pts) experience a sufficient response to first-line (1L) neoadjuvant chemotherapy (NAC) to permit subsequent surgical therapy, the prognostic significance of requiring additional NAC to enable resectability is unknown. We sought to describe the pathologic complete response (pCR) rates, breast cancer-free survival (BCFS) and overall survival (OS) among pts requiring 1 vs &gt;1 lines of NAC prior to surgery. Methods: Upon IRB approval, pts with stage III IBC from 2 academic institutions (Dana-Farber Cancer Institute and MD Anderson Cancer Center) who received 1L or 2-3 lines (2-3L) of NAC prior to surgery were identified. Standard NAC regimens containing different drugs, such as AC-T or TCHP, were considered as 1L. Pts with locoregional progression or metastatic disease prior to surgery were excluded. Hormone receptor (HR), HER2 status, grade, and pCR, defined as no residual invasive cancer in the breast and the axilla, were evaluated. BCFS, defined as time from surgery to locoregional and/or distant recurrence, and OS, defined as time from surgery to death, were evaluated by the Kaplan-Meier method. Multivariable Cox models stratified by institution and containing the covariates pCR and tumor subtype were utilized to estimate the HR of 2-3L vs. 1L of therapy. Results: 808 eligible pts diagnosed between 1997 and 2020 were identified. 733 (91%) had 1L and 75 (9%) had 2-3L of NAC, and the median age was 50 years. 295 (37%) had HER2+, 282 (35%) HR+HER2-, 211 (26%) had HR-HER2- disease and for 20 (2%) pts, the receptor status was unknown. The median time from diagnosis to surgery was 6 months. Grade III disease, triple-negative and HER2-positive disease were more prevalent in pts receiving 2-3L of therapy (table). pCR was achieved in 178 (24%) pts receiving 1L of NAC, and in 14 (19%) pts receiving 2-3L of NAC. At 68 months of median follow-up, 417 (52%) pts experienced a recurrence with 376 in the 1L group and 41 in the 2-3L group. The 5-year BCFS was shorter for the 2-3L group compared to the 1L group (33% v 46%, HR=1.37; 95% CI:0.99-1.91). However, in 192 pts with a pCR, BCFS was similar, regardless of the number of NAC lines. There were 38 recurrences among 178 1L pts, and 3 recurrences among 14 2-3L pts, resulting in BCFS of 76% and 83% in 1L and 2-3L pts, respectively. Overall, there were 308 deaths, 276 deaths among 1L pts and 32 among 2-3L pts. The 5-yr OS estimate in 1L versus 2-3L pts was 60% versus 53% (HR=1.32, 95% CI: 0.91-1.93). Conclusion: Among pts with stage III IBC, pCR was observed among 24% who had 1L and 19% of pts who required 2-3L of NAC. BCFS and OS were comparable among pts with pCR after 1L and 2-3L. Our results suggest the need to continue to optimize current treatment strategies in IBC to improve pCR rates across all disease subtypes regardless of the number of lines of NAC required.

Citation Format: Faina Nakhlis, Samuel Niman, Naoto T. Ueno, Elizabeth Troll, Sean Ryan, Eren Yeh, Laura Warren, Jennifer Bellon, Beth Harrison, Toshiaki Iwase, H. T. Carisa Le-Petross, Sadia Saleem, Mediget Teshome, Gary J. Whitman, Wendy Woodward, Beth Overmoyer, Sara Tolaney, Meredith Regan, Filipa Lynce, Rachel M. Layman. Long-term Outcomes After 1 or 2-3 Lines of Neoadjuvant Therapy in Stage III Inflammatory Breast Cancer [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 P4-07-14.

EGFR is a master switch between immunosuppressive and immunoactive tumor microenvironment in inflammatory breast cancer

Inflammatory breast cancer (IBC), the most aggressive breast cancer subtype, is driven by an immunosuppressive tumor microenvironment (TME). Current treatments for IBC have limited efficacy. In a clinical trial (NCT01036087), an anti-EGFR antibody combined with neoadjuvant chemotherapy produced the highest pathological complete response rate ever reported in patients with IBC having triple-negative receptor status. We determined the molecular and immunological mechanisms behind this superior clinical outcome. Using novel humanized IBC mouse models, we discovered that EGFR-targeted therapy remodels the IBC TME by increasing cytotoxic T cells and reducing immunosuppressive regulatory T cells and M2 macrophages. These changes were due to diminishing immunosuppressive chemokine expression regulated by transcription factor EGR1. We also showed that induction of an immunoactive IBC TME by an anti-EGFR antibody improved the antitumor efficacy of an anti-PD-L1 antibody. Our findings lay the foundation for clinical trials evaluating EGFR-targeted therapy combined with immune checkpoint inhibitors in patients with cancer.

Emerging drug targets for triple-negative breast cancer: A guided tour of the preclinical landscape

INTRODUCTION

Triple-negative breast cancer (TNBC) is the most fatal molecular subtype of breast cancer because of its aggressiveness and resistance to chemotherapy. FDA-approved therapies for TNBC are limited to poly(ADP-ribose) polymerase inhibitors, immune checkpoint inhibitors, and trophoblast cell surface antigen 2-targeted antibody-drug conjugate. Therefore, developing a novel effective targeted therapy for TNBC is an urgent unmet need.

AREAS COVERED

In this narrative review, we discuss emerging targets for TNBC treatment discovered in early translational studies. We focus on cancer cell membrane molecules, hyperactive intracellular signaling pathways, and the tumor microenvironment (TME) based on their druggability, therapeutic potency, specificity to TNBC, and application in immunotherapy.

EXPERT OPINION

The significant challenges in the identification and validation of TNBC-associated targets are 1) application of appropriate genetic, molecular, and immunological approaches for modulating the target, 2) establishment of a proper mouse model that accurately represents the human immune TME, 3) TNBC molecular heterogeneity, and 4) failure translation of preclinical findings to clinical practice. To overcome those difficulties, future research needs to apply novel technology, such as single-cell RNA sequencing, thermostable group II intron reverse transcriptase sequencing, and humanized mouse models. Further, combination treatment targeting multiple pathways in both the TNBC tumor and its TME is essential for effective disease control.

Abstract PD10-08: Remodeling the inflammatory breast cancer tumor microenvironment to enhance immunotherapy: Novel therapeutic development

Background: Inflammatory breast cancer (IBC) is the most lethal and aggressive form of breast cancer, yet no targeted therapy has been approved specifically for this disease. There is a critical need for innovative treatment approaches for patients with IBC. There is a paucity of data on immune checkpoint inhibitors (ICIs) in IBC, yet a strong biological rationale exists to lay the groundwork for testing the efficacy of ICIs in IBC. We have previously shown that an anti–epidermal growth factor receptor (EGFR) antibody, panitumumab (sponsored by Amgen), combined with Abraxane (sponsored by Bristol Myers Squibb), and carboplatin followed by 5-fluorouracil, epirubicin, and cyclophosphamide achieves a very high pathologic complete response (42%) in patients with triple-negative receptor status (TN-IBC) (NCT01036087). We hypothesize that inducing a broad shift in the IBC tumor microenvironment (TME), a critical driver of the IBC clinical phenotype and metastasis, from an immunosuppressive to an immunoreactive phenotype can enhance the efficacy of ICIs. Here we report the impact of targeting EGFR on ICI effectiveness by modulating the immunosuppressive TME in TN-IBC. Methods: We examined the effects of panitumumab on components of the immune TME in IBC patient tissues collected before and after panitumumab treatment. Furthermore, we analyzed panitumumab effects in an IBC SUM149 humanized mouse model (SUM149-hu-NSG-SGM3) by using multiplex immunofluorescence staining (mIF) of single-cell RNA-sequencing (scRNA-seq) and multicolor flow cytometry. We examined the changes in chemokines in humanized mouse tissue after panitumumab treatment using a cytokine antibody array and enzyme-linked immunosorbent assay (ELISA). We also studied the mechanism of EGFR regulation of immunosuppressive chemokine expression via transcription factor EGR1 by using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and chromatin immunoprecipitation (ChIP) assays. In addition, we tested the efficacy of panitumumab combined with anti-PD-L1 antibody (Bio X Cell, clone 29E.2A3) in reducing IBC tumor growth in a humanized IBC SUM149 mouse model. Results: IBC patients who achieved pathologic complete response after receiving panitumumab/neoadjuvant chemotherapy had increased levels of CD8+ T-cells and decreased levels of M2 macrophages and T-reg cells. In the humanized mouse model, panitumumab treatment reduced IBC tumor growth and increased immune response that favors an antitumor effect, as shown by scRNA-seq, flow cytometry, and mIF analyses. In addition, we observed that panitumumab treatment increased the expression of chemokines that function as a chemoattractant for CD8+ T-cells, including CXCL10, CCL4, and CXCL9. We also observed that panitumumab treatment reduced EGR1 expression, leading to the downregulation of chemokines involved in the recruitment of immunosuppressive M2 macrophages and T-reg cells, including CCL2, CCL20 CXCL5, and IL-8. Finally, panitumumab enhanced the reduction in tumor growth by anti-PD-L1 antibody treatment; furthermore, the combination of panitumumab and anti-PD-L1 antibody increased the presence of CD8+ T-cells and reduced the presence of T-reg cells and M2 macrophages more effectively than either treatment alone. Conclusion: Panitumumab treatment converts the immunosuppressive IBC TME to an immunoreactive status by modulating the global expression of chemokines by downregulating the EGR1 transcription factor. This modulation of the TME by panitumumab improves the inhibition of IBC tumor growth by an ICI. Our study is the first to demonstrate that targeting the EGFR/EGR1 axis remodels the IBC TME by regulating chemokine expression, thus boosting the antitumor immune response in IBC and response to ICI.

Citation Format: Xiaoping Wang, Takashi Semba, Ganiraju C. Manyam, Jing Wang, Shan Shao, Francois Bertucci, Pascal Finetti, Savitri Krishnamurthy, Lan ThiHanh Phi, Troy Pearson, Jared K. Burks, Evan N. Cohen, James M. Reuben, Fei Yang, Hu Min, Nicholas Navin, Toshiaki Iwase, Yichao Shen, Xiang Zhang, Debu Tripathy, Naoto T. Ueno. Remodeling the inflammatory breast cancer tumor microenvironment to enhance immunotherapy: Novel therapeutic development [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 PD10-08.

Abstract P5-07-03: Disease classification modeling of inflammatory breast cancer based on simultaneous profiling of coding and non-coding RNAs in tumor and blood samples by TGIRT-sequencing

Background: Inflammatory breast cancer (IBC) is the most aggressive and lethal breast cancer subtype but lags in disease-specific RNA biomarkers due in part to its paucity of large discrete tumors. A strategy to overcome this challenge is to identify blood-based RNA biomarkers that are minimally invasive and reflect the state of both the diseased breast tissue and the patient's immune response. Here, we identified IBC-specific RNA biomarkers by thermostable group II intron reverse transcriptase sequencing (TGIRT-seq), a recently developed comprehensive RNA-seq technology that enables simultaneous profiling of all RNA biotypes from small amounts of starting material. We used these biomarkers to develop novel disease classification models for IBC based on coding and non-coding RNAs from FFPE tumor slices, PBMCs, and plasma. Methods: We obtained biological samples including FFPE, PBMC, and plasma from a cohort of ten patients with IBC and compared them to samples from six patients with non-IBC and sixteen healthy donors using TGIRT-seq technology. Results: TGIRT-seq of FFPE tumor slices identified differentially expressed mRNAs and miRNAs found previously to distinguish IBC from non-IBC tumors, as well as numerous additional differentially expressed mRNAs and small non-coding RNAs characteristic of IBC. Surprisingly, TGIRT-seq revealed that the differentially expressed protein-coding gene transcripts fall into two categories: mature mRNAs with reads confined to exons, and pre-mRNAs-derived transcripts with reads distributed across exons and introns, to our knowledge, a distinction not made previously for any cancer type. Differentially expressed miRNAs included both mature miRNAs and other transcripts of miRNA loci. IBC PBMCs showed a characteristic inflammatory response not seen in PBMCs from non-IBC patients, as well as differentially expressed tRNAs, snoRNAs, and other sncRNAs, while plasma samples, although of variable quality, included coding and non-coding RNAs distinctive of IBC. Classification models using panels consisting of sets of 50 selected biomarkers profiled by TGIRT-seq achieved a high degree of accuracy under cross-validation, with models based on PBMCs and plasma RNAs correlating with those based on tumor RNAs, and models using both coding and non-coding RNA biomarkers outperforming those based on either alone. Conclusions: Our findings are the first to define a distinct IBC profile across three different tissue types and advance TGIRT-seq as a promising method for high-resolution RNA biomarker profiling of both primary tumors and liquid biopsies with potentially broad utility for diagnosing and defining treatment response in IBC and other cancers. COI: Thermostable group II intron reverse transcriptase (TGIRT) enzymes and methods for their use are the subject of patents and patent applications that have been licensed by the University of Texas to InGex, LLC. A.M.L., some former and present members of the Lambowitz laboratory, and the University of Texas are minority equity holders in InGex, and receive royalty payments from the sale of TGIRT enzymes and kits and from sublicensing of intellectual property to other companies.

Citation Format: Dennis C. Wylie, Xiaoping Wang, Jun Yao, Hengyi Xu, Toshiaki Iwase, Savitri Krishnamurthy, Naoto T. Ueno, Alan M. Lambowitz. Disease classification modeling of inflammatory breast cancer based on simultaneous profiling of coding and non-coding RNAs in tumor and blood samples by TGIRT-sequencing [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 P5-07-03.

A Novel Immunomodulatory 27-Gene Signature to Predict Response to Neoadjuvant Immunochemotherapy for Primary Triple-Negative Breast Cancer

Simple Summary

Through analysis of specimens from patients with primary triple-negative breast cancer (TNBC) enrolled in a neoadjuvant clinical trial assessing durvalumab with chemotherapy, we confirmed a novel 27-gene immuno-oncology (IO) signature that generates an IO score to predict the pathologic complete response (pCR) of primary TNBC to neoadjuvant immunotherapy with the PD-L1 blocker durvalumab with chemotherapy. Combining the 27-gene IO signature with PD-L1 immunohistochemistry strengthened the model’s predictive power of the pCR. Furthermore, the comprehensive computational analysis revealed that the 27-gene IO signature corresponded with an immunogenic tumor microenvironment.

Abstract

A precise predictive biomarker for TNBC response to immunochemotherapy is urgently needed. We previously established a 27-gene IO signature for TNBC derived from a previously established 101-gene model for classifying TNBC. Here we report a pilot study to assess the performance of a 27-gene IO signature in predicting the pCR of TNBC to preoperative immunochemotherapy. We obtained RNA sequencing data from the primary tumors of 55 patients with TNBC, who received neoadjuvant immunochemotherapy with the PD-L1 blocker durvalumab. We determined the power and accuracy in predicting pCR for the immunomodulatory (IM) subtype identified by the 101-gene model, the 27-gene IO signature, and PD-L1 expression by immunohistochemistry (IHC). The pCR rate was 45% (25/55). The odds ratios for pCR were as follows: IM subtype by 101-gene model, 3.14 (p = 0.054); 27-gene IO signature, 4.13 (p = 0.012); PD-L1 expression by IHC, 2.63 (p = 0.106); 27-gene IO signature in combination with PD-L1 expression by IHC, 6.53 (p = 0.003). The 27-gene IO signature has the potential to predict the pCR of primary TNBC to neoadjuvant immunochemotherapy. Further analysis in a large cohort is needed.

Changes in Overall Survival over Time for Patients with de novo Metastatic Breast Cancer

The purpose of this study was to determine the change in overall survival (OS) for patients with de novo metastatic breast cancer (dnMBC) over time. We conducted a retrospective cohort study with 1981 patients with dnMBC diagnosed between January 1995 and December 2017 at The University of Texas MD Anderson Cancer Center. OS was measured from the date of diagnosis of dnMBC. OS was compared between patients diagnosed during different time periods: 5-year periods and periods defined according to when key agents were approved for clinical use. The median OS was 3.4 years. The 5- and 10-year OS rates improved over time across both types of time periods. A subgroup analysis showed that OS improved significantly over time for the estrogen-receptor-positive/HER2-positive (ER+/HER2+) subtype and exhibited a tendency toward improvement over time for the ER-negative (ER-)/HER2+ subtype. In addition, median OS was significantly longer in patients with non-inflammatory breast cancer (p = 0.02) and patients with ER+ disease, progesterone-receptor-positive disease, HER2+ disease, lower nuclear grade, locoregional therapy, and metastasis to a single organ (all p < 0.0001). These findings showed that OS at 5 and 10 years after diagnosis in patients with dnMBC improved over time. The significant improvements in OS over time for the ER+/HER2+ subtype and the tendency toward improvement for the ER-/HER2+ subtype suggest the contribution of HER2-targeted therapy to survival.

Pathological complete response of adding targeted therapy to neoadjuvant chemotherapy for inflammatory breast cancer: A systematic review

Background

The current use of targeted therapy plus neoadjuvant chemotherapy for inflammatory breast cancer (IBC) is based on data extrapolated from studies in non-IBC. We conducted a systematic review to determine whether neoadjuvant chemotherapy plus targeted therapy results in a higher pathologic complete response (pCR) rate than neoadjuvant chemotherapy alone in patients with IBC.

Method and findings

This systematic review was registered in the PROSPERO register with registration number CRD42018089465. We searched MEDLINE & PubMed, EMBASE, and EBSCO from December 1998 through July 2020. All English-language clinical studies, both randomized and non-randomized, that evaluated neoadjuvant systemic treatment with or without targeted therapy before definitive surgery and reported the pCR results of IBC patients. First reviewer extracted data and assessed the risk of bias using the Risk of Bias In Non-randomized Studies of Interventions tool. Second reviewer confirmed the accuracy. Studies were divided into 3 groups according to systemic treatment: chemotherapy with targeted therapy, chemotherapy alone, and high-dose chemotherapy with hematopoietic stem cell support (HSCS). Of 995 screened studies, 23 with 1,269 IBC patients met the inclusion criteria. For each of the 3 groups of studies, we computed a weighted average of the pCR rates across all studies with confidence interval (CI). The weighted averages (95% CIs) were as follows: chemotherapy with targeted therapy, 31.6% (26.4%-37.3%), chemotherapy alone, 13.0% (10.3%-16.2%), and high-dose chemotherapy with HSCS, 23.0% (18.7%-27.7%). The high pCR by targeted therapy group came from anti-HER2 therapy, 54.4% (44.3%-64.0%). Key limitations of this study included no randomized clinical studies that included only IBC patients.

Conclusion

Neoadjuvant chemotherapy plus targeted therapy is more effective than neoadjuvant chemotherapy alone for IBC patients. These findings support current IBC standard practice in particular the use of anti-HER2 targeted therapy.

Abstract PS2-23: Prospective study of circulating cancer-associated macrophage-like cells (CAMLs) in obese patients with advanced breast cancer

Background

Cancer-associated macrophage-like cells (CAMLs) are rare circulating gigantic atypical cells exclusively found in the peripheral blood of patients with solid cancers. CAMLs potentially originate from tumor-associated macrophages in the tumor microenvironment and may have a prognostic role in breast cancer. Obesity-induced local hypoxia attracts macrophages to the tumor microenvironment and activates macrophages to induce chronic inflammation, which can lead to breast cancer progression. However, little is known about the relationship between CAMLs, obesity, and body fat distribution. Also, the role of the CAMLs on breast cancer development needs to be investigated. We hypothesized that the number and size of CAMLs are correlated with body mass index (BMI), and we investigated the relationship between CAMLs and body composition.

Materials and methods

We prospectively collected 10 ml of peripheral blood from 30 patients initially diagnosed with advanced breast cancer who underwent computed tomography. Blood samples were drawn in CellSave tubes to preserve peripheral blood mononuclear cells. We used the CellSieve microfiltering system to isolate and identify CAMLs. After enumerating cells, we analyzed immunofluorescent staining for DAPI, CD14, CD45, CXCR4, and cytokeratin. CAMLs were identified by cell surface markers (CD14+, CD45+, and cytokeratin+) and morphology (multinuclear and giant cells &gt;30 µm). BMI was measured at the time of diagnosis. The in-house 3D imaging analysis software Medical Executable for the Efficient and Robust Quantification of Adipose Tissue was used to calculate the total amount of abdominal visceral fat tissue (VAT) and subcutaneous fat tissue (SAT) between the upper diaphragm and pelvic end using multi-detector computed tomography data. The VAT:SAT ratio was also calculated. We quantified the expression of C-X-C chemokine receptor type 4 (CXCR4) in CAMLs to investigate the metastatic potential of the cells. Finally, we determined the relationship between the characteristics of CAMLs and BMI, body composition parameters, and CXCR4 using the Pearson correlation test.

Results

Of 30 collected samples, two had an inadequate amount of blood for evaluation. Among the remaining 28, we detected CAMLs in 24. The median BMI was 30.4 kg/m2, and half of the patients were categorized as obese by the World Health Organization BMI classification. BMI was correlated with the number (r=0.39, p=0.043), average size (r=0.42, p=0.039), and maximum size (r=0.50, p=0.013) of CAMLs. In body composition analysis, the maximum size of CAMLs was correlated with the total amount of VAT (r=0.51, p=0.012) and SAT (r=0.44, p=0.037) but not the VAT:SAT ratio. The number of CAMLs was correlated with maximum CXCR4 expression in CAMLs (r=0.58, p=0.004). CAMLs size and CXCR4 expression were inversely correlated.

Conclusion

The number and size of CAMLs are correlated with BMI, but CAMLs characteristics are not related to body composition. The number of CAMLs was associated with CXCR4, which indicated its metastatic potential. Further studies are needed to elucidate the biological role of CAMLs, especially whether the increased number and size of CAMLs in obesity reflect the tumor microenvironment.

Citation Format: Toshiaki Iwase, Aaroh Parikh, Onur Sahin, Akshara S Raghavendra, Maryanne E Sapon, Anjali James, Tushaar V Shrimanker, Sudpreeda Chainitikun, Kumiko Kida, Daniel L Adams, Cha-Mei Tang, Andrea YD Medrano, Ann H Klopp, Naoto T Ueno. Prospective study of circulating cancer-associated macrophage-like cells (CAMLs) in obese patients with advanced 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 PS2-23.

Abstract PS4-07: Identification of novel molecules that enhance neratinib efficacy in triple-negative breast cancer by high-throughput RNA interference

Background: Neratinib is a potent, irreversible pan-HER inhibitor that inhibits the ErbB family members EGFR, HER2, and HER4 and downstream signal transduction of these receptors. Triple-negative breast cancer (TNBC) is a heterogeneous disease that lacks druggable levels of receptors for estrogen, progesterone and HER2 and therefore challenging to treat. There is evidence that some cases of TNBC have activated signaling pathways mediated by ErbB family members that may contribute to aggressive behavior. The purpose of this preclinical study was to identify and validate kinases whose targeting may enhance the antitumor activity of neratinib in TNBC cell lines. Methods: In vitro proliferation assays were used to evaluate the efficacy of neratinib in TNBC cell lines. Baseline and post-neratinib-treatment expression of EGFR and phosphorylated EGFR (phospho-EGFR) were assessed via Western blot analysis in 18 TNBC cell lines. Reverse-phase protein array (RPPA) was used to profile and validate the signaling networks induced by neratinib. To identify potential targets or pathways that may synergize with neratinib treatment, we performed high-throughput RNA interference (HT RNAi) screening using a 709-kinome library. CellTiter-Blue, sulforhodamine B, and soft-agar assays were performed to evaluate the antiproliferative effect of neratinib alone and with target inhibitor. Mammary fat pad xenograft models were used to evaluate the efficacy of neratinib alone or with inhibitor in vivo. Results: In vitro proliferation assays showed that the half-maximal inhibitory concentration (IC50) of neratinib in tested TNBC cell lines ranged from 0.16 µM to 1.25 µM. RPPA and Western blot analyses revealed that the efficacy of neratinib correlated with phospho-EGFR expression levels across the TNBC cell lines tested (R2 = 0.3245). Among the tested TNBC cell lines, SUM149 cells (PIK3CA wild-type) were selected for high throughput RNAi screening because this cell line has high EGFR expression and is moderately sensitive to neratinib (IC50 = 0.35 µM). We identified the 40 most relevant kinase targets by the sensitivity index analysis, and further pathway analysis identified PI3K/AKT/mTOR (drug: everolimus) and MAPK (drug: trametinib) as major canonical pathways whose targeting enhanced the cytotoxic effect of neratinib. Everolimus (mTOR inhibitor) produced a strong antiproliferative effect when combined with neratinib in most tested TNBC cell lines (12 of 15 cell lines; combination index [CI] values, 0.1-0.5) and was more effective in PIK3CA-mutated compared to wildtype cell lines. Trametinib (MEK inhibitor) showed a moderate antiproliferative effect (effective in 10 of 15 cell lines; CI values, 0.2-0.9). Synergistic antitumor effects of neratinib combined with everolimus or with trametinib were also observed in anchorage-independent growth conditions (P &lt; 0.05). In vivo experiments demonstrated that neratinib plus everolimus and neratinib plus trametinib combinations inhibited tumor growth in the SUM149 xenograft model for than single drug (neratinib, 42.3% growth inhibition; everolimus, 29.7%; trametinib, 47.1%; neratinib plus everolimus, 69.7%; neratinib plus trametinib, 77.7%; P &lt; 0.0001). Conclusion: Combining neratinib with everolimus or with trametinib enhanced the antitumor effects of these drugs in TNBC regardless of PIK3CA mutation status, and clinical investigations evaluating these combination regimens for the treatment of TNBC are warranted.

Citation Format: Jangsoon Lee, Troy Pearson, Huey Liu, Jon A. Fuson, Toshiaki Iwase, Irmina Diala, Alshad S. Lalani, Lisa D. Eli, Debu Tripathy, Bora Lim, Naoto T. Ueno. Identification of novel molecules that enhance neratinib efficacy in triple-negative breast cancer by high-throughput RNA interference [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 PS4-07.

Body composition and breast cancer risk and treatment: mechanisms and impact

PURPOSE

The purpose of this review is to clarify the association of body composition with breast cancer risk and treatment, including physiological mechanisms, and to elucidate strategies for overcoming unfavorable body composition changes that relate to breast cancer progression.

METHODS

We have summarized updated knowledge regarding the mechanism of the negative association of altered body composition with breast cancer risk and treatment. We also review strategies for reversing unfavorable body composition based on the latest clinical trial results.

RESULTS

Body composition changes in patients with breast cancer typically occur during menopause or as a result of chemotherapy or endocrine therapy. Dysfunction of visceral adipose tissue (VAT) in the setting of obesity underlies insulin resistance and chronic inflammation, which can lead to breast cancer development and progression. Insulin resistance and chronic inflammation are also observed in patients with breast cancer who have sarcopenia or sarcopenic obesity. Nutritional support and a personalized exercise program are the fundamental interventions for reversing unfavorable body composition. Other interventions that have been explored in specific situations include metformin, testosterone, emerging agents that directly target the adipocyte microenvironment, and bariatric surgery.

CONCLUSIONS

A better understanding of the biology of body composition phenotypes is key to determining the best intervention program for patients with breast cancer.

AB0435 RISK OF SERIOUS INFECTION IN LUPUS NEPHRITIS AND RHEUMATOID ARTHRITIS MEASURED USING THE JAPANESE REAL WORLD HOSPITAL CLAIMS DATABASE

Background:

Patients with lupus nephritis (LN) and rheumatoid arthritis (RA) are at risk of serious infections (SIs) due to the impact of the disease itself and treatments that modulate immune system. Though the epidemiology of RA has been well-established by developing many targeted DMARDs (tDMARDs) including biologics and targeted synthesized DMARDs, LN is a very rare disease. Therefore, a large sample size with a significant number of cases is required to determine the exact risk of SIs in LN.

Objectives:

To compare the incidence rates of SIs resulting in an inpatient claim in adult patients with LN compared with RA with or without tDMARDs using hospital claims data in Japan.

Methods:

LN and RA were identified using claims data provided by Medical Data Vision Co., Ltd (Tokyo, Japan) between April 2008 and June 2019 which was extracted 5thSeptember 2019. Data between January 2010 and December 2018 was used for analysis. Patients with LN and RA were identified using modifications to algorithms developed before [1, 2]. LN patients were required to have continuous insurance claim for both systemic lupus erythematosus (SLE) and LN for ≥ 6 months after index date and then RA patients had continuous insurance claim for RA for ≥ 6 months after index date. First incident SIs were defined as those that resulted in an inpatient claim for a pre-specified set of ICD-10 code. Incidence rates (IRs) were calculated along with 95% confidence intervals (CI).

Results:

The LN, RA, RA treated with tDMARDs and RA treated without tDMARDs cohorts included 6,403, 108,317, 16,450, and 91,867 patients, respectively. As anticipated, the LN and RA cohorts were predominantly female and the RA cohort was generally older than the LN cohorts. IRs per 1,000 person-year(PY) [95% CI] for pneumocystis carini pneumonia were 28.2 [26.0-30.4] in LN, 8.5 [8.2-8.8] in RA, 12.6 [11.7-13.5] in RA with tDMARDs and 7.7 [7.4-8.0] in RA without tDMARDs. IRs per 1,000 PY for septicaemia infection were 23.3 [21.3-25.3] in LN, 12.1 [11.7-12.4] in RA, 13.3 [12.3-14.2] in RA with tDMARDs and 11.8 [11.5-12.2] in RA without tDMARDs. IRs per 1,000 PY for cytomegalovirus infection were 13.4 [11.9-14.9] in LN, 4.4 [4.2-4.6] in RA, 6.2 [5.6-6.8] in RA with tDMARDs and 4.1 [3.8-4.3] in RA without tDMARDs. IRs per 1,000 PY for tuberculosis were 7.2 [6.0-8.3] in LN, 6.7 [6.5-7.0] in RA, 18.2 [17.1-19.3] in RA with tDMARDs and 4.4 [4.2-4.7] in RA without tDMARDs.

Conclusion:

In this population-based analysis of claims data from Japan, the IRs of SI such as pneumocystis carini pneumonia, septicemia infection and cytomegalovirus infection were higher in LN than in RA. And also, the incidence of tuberculosis in RA treated with tDMARDs was highest among these cohorts. These findings demonstrate the relative contribution of age, immunosuppressive therapies and disease-related factors in LN and RA.

References:

[1]Pawar A, et al. Ann Rheum Dis. 2019 Apr;78(4):456-464. [2] ChibnikLB et al. Lupus, 2010. May;19(6):741-3.

Table 1.

Description of study population

LNRAtDMARDsNon tDMARDsN%N%N%N%Age (years) 18-34170026.690158.3182811.171877.8 35-44174327.21666215.4281617.11384615.1 45-54156324.42995527.7445227.12550327.8 55-64139721.85268548.6735444.74533149.3Gender Female538584.17841972.41265376.96576671.6 Male101815.92989827.6379723.12610128.4Table 2.

IRs per 1,000 PY [95% CI] of SI for LN and RA patients

LN total PY = 22065RA total PY = 365033tDMARDsNon tDMARDstotal PY = 60999total PY = 304034Pneumocystis carinipneumonia28.2 [26.0-30.4]8.5 [8.2-8.8]12.6 [11.7-13.5]7.7 [7.4-8.0]Septicaemia23.3 [21.3-25.3]12.1 [11.7-12.4]13.3 [12.3-14.2]11.8 [11.5-12.2]Cytomegalovirusinfection13.4 [11.9-14.9]4.4 [4.2-4.6]6.2 [5.6-6.8]4.1 [3.8-4.3]Tuberculosis7.2 [6.0-8.3]6.7 [6.5-7.0]18.2 [17.1-19.3]4.4 [4.2-4.7]Mycosis5.1 [4.1-6.0]2.7 [2.6-2.9]4.6 [4.1-5.1]2.4 [2.2-2.5]Aspergillosis4.7 [3.8-5.6]2.7 [2.5-2.9]2.1 [1.7-2.5]2.8 [2.6-3.0]Herpes3.3 [2.5-4.0]2.4 [2.2-2.6]2.9 [2.5-3.3]2.3 [2.1-2.5]

Disclosure of Interests:

Mariko Nio Employee of: Chugai Pharmaceutical Co., Ltd., Kosei Tajima Employee of: Chugai Pharmaceutical Co., Ltd., Naofumi Sugaya Employee of: Chugai Pharmaceutical Co., Ltd., Tomoyuki Ishiwata Employee of: Chugai Pharmaceutical Co., Ltd., Tatsuhiko Iwase Employee of: Chugai Pharmaceutical Co., Ltd., hiroyuki kato Employee of: Chugai Pharmaceutical Co., Ltd., Misato Hashizume Employee of: Chugai Pharmaceutical Co., Ltd.

Validation of an immunomodulatory gene signature algorithm to predict response to neoadjuvant immunochemotherapy in patients with primary triple-negative breast cancer

3117

Background: A 101-gene algorithm established as a molecular subtyping method for triple-negative breast cancer (TNBC) includes assignment of an immunomodulatory (IM) subtype based on genes active in immune cell processes. Recently, we isolated the IM concept to an independent 27-gene algorithm and its predictive ability for immunotherapy response was demonstrated in lung cancer. The objective of this study was to validate the predictive accuracy of the IM subtype as determined by the 27-gene algorithm for pathological complete response (pCR) compared with PD-L1 immunohistochemistry (IHC) staining in TNBC. Methods: We obtained RNA sequencing data from pretreatment core needle biopsies in 55 patients with stage I-III primary TNBC who received neoadjuvant immunotherapy (durvalumab with weekly nab-paclitaxel followed by ddAC) in phase I/II trial (NCT02489448). The 27-gene algorithm was used to determine IM positivity using a cutoff point previously validated from 71 lung cancer biopsy patients treated with immunotherapy. Results from the algorithm and PD-L1 IHC (antibody, SP263) were compared with pCR. Predictive accuracy of both methods was determined by diagnostic indicators. In cases positive for the IM subtype and pCR, we analyzed the immune microenvironment by deconvoluting the immune infiltration using a computational algorithm. Results: Of the 55 patients, 25 (45%) had pCR. Compared with previous subtyping methods, the 27-gene algorithm showed stronger predictive value (odds ratio, 4.125; 95% CI, 1.36-13.47; P < 0.015). For PD-L1 IHC, the odds ratio was 2.63 (95% CI, 0.82-9.21; P = 0.11). The positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for PD-L1 IHC were 0.55, 0.68, 1.43, and 0.54, respectively. For the 27-gene algorithm, these metrics were 0.65, 0.69, 2.09, and 0.51, indicating its superior accuracy for predicting pCR. The computational algorithm showed that the IM subtype and pCR were negatively associated with a macrophage-enriched microenvironment. CD4+ T cells and dendritic cells were significantly increased among the baseline immune cell population in IM-positive patients. Conclusions: We conclude that 27-gene algorithm is a clinically applicable and a possible predictive marker for response to neoadjuvant immunochemotherapy for patients with primary TNBC. Our immune microenvironment results suggest that antigen-presenting immune cells have a crucial role in immunochemotherapy response.

The efficacy of first-line chemotherapy in endocrine-resistant hormone receptor-positive (HR+), human epidermal growth factor receptor 2- negative (HER2-) metastatic breast cancer (MBC)

1056

Background: Combinations of endocrine therapy (ET) and targeted therapy (CDK4/6 or mTOR inhibitors) are standard of care for HR+/HER2- MBC. When ET is not effective, chemotherapy is commonly used. However, clinical outcomes of chemotherapy in the endocrine-resistant setting are limited. We hypothesized that clinicopathological baseline and prior ET factors determine chemotherapy’s efficacy. We sought to identify predictive factors and the compare efficacies of chemotherapy agents in endocrine-resistant MBC. Methods: We conducted a retrospective study of patients with HR+/HER2- MBC who received chemotherapy after progression on ET with or without targeted therapy at MD Anderson Cancer Center from 1999-2017. We collected baseline clinicopathological and all treatment data. The primary endpoint was time to treatment failure (TTF) of first-line chemotherapy for MBC. We performed univariate and multivariate analyses using the Cox proportional hazard model. Kaplan-Meier methods were used to analyze TTF. Results: In the 1,258 patients analyzed, the mean age was 55.3 years (range 21-91). Forty-five patients (3.6%) had inflammatory breast cancer (IBC). Three hundred ninety patients (31%) received previous targeted therapy: 264 with CDK4/6 inhibitor, 205 with mTOR inhibitor, and 79 with both. The most frequent chemotherapy agents were capecitabine (48.9%) and taxanes (paclitaxel, nab-paclitaxel, or docetaxel; 28.6%). After adjustment for all factors in a multivariate model, IBC and prior exposure to a CDK4/6 inhibitor were significantly associated with shorter TTF. Previous treatment with a CDK4/6 inhibitor had the strongest negative effect on chemotherapy TTF regardless of ET duration (adjusted hazard ratio [HR] 1.84; 95%CI 1.49-2.27; p < 0.001). Capecitabine had significantly longer median TTF than taxanes regardless of whether patients had prior exposure to taxanes in (neo)adjuvant setting (6.1 vs 4.9 months; HR 0.64; 95%CI 0.55-0.75; p < 0.001). Conversely, the median TTF for taxanes was shorter in patients who received prior (neo)adjuvant taxanes than in those who did not (4.5 vs 5.1 months). Conclusions: Previous exposure to CDK4/6 inhibitor had a negative predictive effect for the efficacy of chemotherapy. Capecitabine had the best efficacy against endocrine-resistant breast cancer.

Quantitative hormone receptor (HR) expression and gene expression analysis in HR+ inflammatory breast cancer (IBC) vs non-IBC

Background

The purpose of this study was to determine the prognostic role of hormone receptor (HR) on inflammatory breast cancer (IBC) to elucidate its aggressive biological behavior.

Methods

We evaluated the expression of estrogen receptor (ER) and progesterone receptor (PR) by immunohistochemical staining and determined the predictive and prognostic role of HR expression on 189 patients with HR+/HER2– IBC and 677 patients with HR+/HER2– stage III non-IBC. Furthermore, we performed gene expression (GE) analyses on 137 patients with HR+/HER2– IBC and 252 patients with HR+/HER2– non-IBC to detect genes that are specifically overexpressed in IBC.

Results

The expression of ER% was significantly associated with longer distant disease-free survival and overall survival. However, there was no significant relationship between ER% and neoadjuvant chemotherapy outcome. In the GE study, 84 genes were identified as significantly distinguishing HR+ IBC from non-IBC. Among the top 15 canonical pathways expressed in IBC, the ERK/MAPK, PDGF, insulin receptor, and IL-7 signaling pathways were associated with the ER signaling pathway. Upregulation of the MYC gene was observed in three of these four pathways. Furthermore, HR+/HER2– IBC had significantly higher MYC amplification, and the genetic alteration was associated with poor survival outcome.

Conclusions

Higher ER expression was significantly associated with improved survival in both HR+/HER2– IBC and HR+/HER2– stage III non-IBC patients. HR+/HER2– IBC had several activated pathways with MYC upregulation, and the genetic alteration was associated with poor survival outcome. The results indicate that MYC may be a key gene for understanding the biology of HR+/HER2– IBC.

Abstract P5-06-10: Validation of prognostic stage and anatomic stage in the American joint committee on cancer 8th edition for inflammatory breast cancer

Background: The American Joint Committee on Cancer (AJCC) recently updated its breast cancer staging system to incorporate biological factors, including estrogen and progesterone receptor (ER, PR), and HER2 status, in the new “prognostic stage” in addition to the traditional TNM anatomic stage. For the clinical anatomic staging, IBCs are classified at T4d; N0-2 as IIIB; and N3 as IIIC. For the clinical prognostic staging, ER+/PR+/HER2+/grade1-2 staged as IIIA; ER+/PR-/HER2-/grade3, ER-/PR+/HER2-/grade3, and all triple-negative cancers staged as IIIC; and all others as IIIB. We undertook this study to validate the clinical prognostic and anatomic stages for inflammatory breast cancer (IBC), an aggressive subgroup. The prognostic staging system, which was developed using non-IBC data, has not been validated in IBC.

Methods: We established two cohorts of IBC patients diagnosed without distant metastasis: (1) patients treated at MD Anderson Cancer Center between 1989 and 2017 (MDA-cohort) and (2) patients registered in the SEER database between 2010 and 2015 (SEER-cohort). Survival endpoints including overall survival (OS), and disease-free survival (DFS) were calculated by the Kaplan-Meier method. Breast cancer-specific survival (BCSS) was calculated by the competing risk analysis. The log-rank test was used to compare differences in endpoints between staging groups. The Harrell concordance index (C index) was used to quantify staging models’ predictive performance. A higher C index indicates a better predictive performance.

Results: We studied 885 patients in the MDA cohort and 338 in the SEER cohort. In the MDA cohort, the prognostic stage upstaged 248 patients (28%) and downstaged 146 (16%) comparing with the anatomic stage. The prognostic stage showed significant predictive power for BCSS, OS, and DFS (all P&lt;0.0001), although the anatomic stage did not. The C index was significantly higher in the prognostic stage than the anatomic stage for BCSS (0.643 vs. 0.526, P&lt;0.0001), OS (0.641 vs. 0.533, P&lt;0.0001) and DFS (0.599 vs. 0.494, P&lt;0.0001). In the SEER cohort, the prognostic stage upstaged 117 patients (27%) and downstaged 73 (17%). The survival differences between staging groups were more prominent with prognostic stage than with anatomic stage. The C index was significantly higher in the prognostic stage than the anatomic stage for BCSS (0.685 vs. 0.550, P=0.0028) and OS (0.681 vs. 0.557, P=0.0008). In both cohorts, prognostic stage IIIA patients had the best survival rates with the 5-year BCSS of 83% in the MDA cohort and 100% in the SEER cohort.

Conclusions: The prognostic stage incorporating biological factors provided more accurate prognostication for IBC patients than the anatomic stage. Our results show that the 8th edition AJCC prognostic staging system is optimal for prognostification in IBC.

Citation Format: Kumiko Kida, Kenneth R Hess, Bora Lim, Toshiaki Iwase, Sudpreeda Chainitikun, Maryanne E Sapon, Vicente Valero, Anthony Lucci, Carisa Le-Petross, Wendy A Woodward, Savitri Krishnamurthy, Gabriel N Hortobagyi, Debu Tripathy, Naoto T Ueno. Validation of prognostic stage and anatomic stage in the American joint committee on cancer 8th edition for inflammatory breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-06-10.

Phase II study of Radium-223 dichloride combined with hormonal therapy for hormone receptor-positive, bone-dominant metastatic breast cancer

Background

Radium‐223 dichloride (Ra‐223) is a targeted alpha therapy that induces localized cytotoxicity in bone metastases. We evaluated the efficacy and safety of Ra‐223 plus hormonal therapy in hormone receptor‐positive (HR+), bone‐dominant metastatic breast cancer.

Methods

In this single‐center phase II study, 36 patients received Ra‐223 (55 kBq/kg intravenously every 4 weeks) up to 6 cycles with endocrine therapy. The primary objective was to determine the clinical disease control rate at 9 months. Secondary objectives were to determine (a) tumor response rate at 6 months, (b) progression‐free survival (PFS) durations, and (c) safety.

Results

The median number of prior systemic treatments for metastatic disease was 1 (range, 0‐4). The disease control rate at 9 months was 49%. The tumor response rate at 6 months was 54% (complete response, 21%; partial, 32%). The median PFS was 7.4 months (95% CI, 4.8‐not reached [NR]). The median bone‐PFS was 16 months (95% CI, 7.3‐NR). There were no grade 3/4 adverse events.

Conclusions

Ra‐223 with hormonal therapy showed possible efficacy in HR+ bone‐dominant breast cancer metastasis, and adverse events were tolerable. We plan to further investigate the clinical application of Ra‐223 in these patients. (NCT02366130).

Quality and quantity of visceral fat tissue are associated with insulin resistance and survival outcomes after chemotherapy in patients with breast cancer

PURPOSE

Recent studies suggest that the quality and quantity of visceral adipose tissue (VAT) play significant roles in adipocyte function, and are related to insulin resistance. We tested the hypothesis that high amounts of upper VAT (aVAT) and low-quality VAT worsen treatment outcomes via altered insulin metabolism.

METHODS

Cohort 1 included 106 women with breast cancer who were undergoing surgery. Homeostasis model assessment of insulin resistance (HOMA-R), insulin-like growth factor (IGF)-1, and IGF-binding protein 3 (IGFBP3) were measured before the initiation of treatment. aVAT was measured via computed tomography (CT). VAT quality was assessed using CT-determined Hounsfield units (VAT-HU). Associations between the variables investigated and VAT quality and quantity were analyzed. Cohort 2 included 271 patients who underwent chemotherapy. Associations between the variables investigated and survival outcomes after chemotherapy were analyzed via retrospective chart review.

RESULTS

In cohort 1, aVAT was significantly correlated with insulin and HOMA-R levels. As body mass index (BMI) class increased, mean IGF-1 increased and mean IGFBP3 decreased, but these trends were not statistically significant. In cohort 2, aVAT was significantly positively correlated with BMI. The patients in the third aVAT tertiles had significantly shorter distant disease-free survival (dDFS) after neoadjuvant chemotherapy setting. In multivariate analysis, aVAT and VAT-HU were significantly associated with shorter dDFS.

CONCLUSIONS

High aVAT and low-quality VAT were associated with poor survival outcome, increased insulin levels, and insulin resistance. The present study suggests the importance of evaluating the quality and quantity of VAT when estimating insulin resistance and treatment outcomes.

A phase Ib study of entinostat plus lapatinib with or without trastuzumab in patients with HER2-positive metastatic breast cancer that progressed during trastuzumab treatment

BACKGROUND

Human epidermal growth factor 2 (HER2) is an effective therapeutic target in breast cancer; however, resistance to anti-HER2 agents such as trastuzumab and lapatinib develops. In a preclinical model, an HDAC inhibitor epigenetically reversed the resistance of cancer cells to trastuzumab and showed synergistic efficacy with lapatinib in inhibiting growth of trastuzumab-resistant HER2-positive (HER2+) breast cancer.

METHODS

A phase 1b, dose escalation study was performed to assess maximum tolerated dose, safety/toxicity, clinical efficacy and explored pharmacodynamic biomarkers of response to entinostat combined with lapatinib with or without trastuzumab.

RESULTS

The combination was safe. The MTD was lapatinib, 1000 mg daily; entinostat, 12 mg every other week; trastuzumab, 8 mg/kg followed by 6 mg/kg every 3 weeks. Adverse events included diarrhoea (89%), neutropenia (31%), and thrombocytopenia (23%). Neutropenia, thrombocytopenia and hypokalaemia were noted. Pharmacodynamic assessment did not yield conclusive results. Among 35 patients with evaluable response, PR was observed in 3 patients and CR in 3 patients, 1 maintained SD for over 6 months.

DISCUSSION

This study identified the MTD of the entinostat, lapatinib, and trastuzumab combination that provided acceptable tolerability and anti-tumour activity in heavily pre-treated patients with HER2+ metastatic breast cancer, supporting a confirmatory trial.

Abstract P4-08-29: Lymphatic invasion is an independent risk factor in patients with small node-negative luminal breast cancer

[Background]

In patients with node-negative (N0), hormone receptor-positive, human epidermal growth factor receptor (HER2) -negative (luminal) breast cancer, the impact of lymphatic invasion (ly) on the prognosis remains to be clarified.

[Methods]

Among 3,158 patients with primary breast cancers who underwent surgery in our institute from January 2007 to December 2009, we analyzed 1027 N0 luminal invasive breast cancers without preoperative systemic therapy. The luminal breast cancer was defined as hormone receptor-positive (ER of ≥ 10% or PgR of ≥ 10%) and HER2-negative (immunohistochemistry: 0, 1+ or FISH: ratio &lt; 2.0) cancer in the postoperative pathological specimen. ly was defined as positive when cancer cell nests were detected within the lymph duct in the whole specimen. N0 was confirmed pathologically by the sentinel lymph node biopsy in all the patients. The Fisher's exact test was used for comparison between different categories. The distant recurrence rate (DRR) was analyzed using the Kaplan-Meier method and the log-rank test. For multivariate analysis, Cox's regression analysis was performed.

[Results]

The median follow-up period was 103.8 months (range: 5.6-128.8). Recurrence with distant metastasis occurred in 26 patients (2.5%). There were 5 (0.7%) deaths related to breast cancer. ly was detected in 240 patients (23.4%). In the ly-positive group, the tumor size was larger (p = 0.007), and the nuclear grade (NG) was higher (p &lt; 0.001) than in the ly-negative group. Postoperative endocrine therapy (p &lt; 0.001) and postoperative chemotherapy (p &lt; 0.001) were more frequently employed for patients with ly-positive tumor. The univariate analysis showed that ly positivity (p &lt; 0.001), large tumor size (p &lt; 0.001), high NG (p &lt; 0.001), PgR negativity (p = 0.002) and the history of adjuvant chemotherapy (p &lt; 0.001) were associated with high DRR. In the multivariate analysis, large tumor size (p = 0.007) and PgR negativity (p = 0.015) remained significant. Although positive ly had a risk ratio of 2.2, it was not an independent risk factor.When restricted to T1 tumor (n = 899), the aforementioned factors still showed prognostic value in the univariate analysis, among which ly positivity (p = 0.004)remained significant together with PgR negativity (p = 0.047)in themultivariate analysis.The 8-year DRR was very favorable (0.8%) in patients with ly-negative T1N0 tumor while it was modest (6.6%) in patients with ly-positive T1N0 tumor (p &lt; 0.001). Only 1.3% of the patients had received adjuvant chemotherapy in the ly-negative group while 27% of the patients had in the ly-positive group.

[Conclusion]

Lymphatic invasion was associated with higher DRR although it was not independent in the multivariate analysis among patients with N0 luminal breast cancer. When restricted to patients with T1N0 luminal breast cancer, the presence of ly was independently associated with higher risk of distant recurrence. It suggests that the assessment of ly is clinically more relevant when considering treatment options for small luminal breast cancer.

Citation Format: Abe T, Ito Y, Fukada I, Shibayama T, Ono M, Kobayashi T, Kobayashi K, Takahashi S, Horii R, Akiyama F, Iwase T, Ueno T, Ohno S. Lymphatic invasion is an independent risk factor in patients with small node-negative luminal breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-29.

Abstract P5-18-11: Prognostic impact and possible pathogenesis of lymph node metastasis in ductal carcinoma in situof the breast

Background: By definition, ductal carcinoma in situ (DCIS) does not metastasize to the lymph nodes. However, since the introduction of molecular whole-node analysis using the one-step nucleic acid amplification (OSNA) assay for sentinel node (SN) biopsies, the number of DCIS patients with SN metastasis has increased. The clinical management of node-positive DCIS remains controversial because these patients can be treated as different stages based on the pathogenesis: e.g. occult invasive cancer with true nodal metastasis (T1N1) or true DCIS with iatrogenic dissemination of benign or tumor cells into lymph node (TisN0). In this retrospective cohort study, we aimed to elucidate the pathogenesis of nodal metastasis in DCIS and the clinical management of node-positive DCIS.

Patients and Methods: Subjects comprised of 427 patients with a routine postoperative diagnosis of DCIS who underwent SN biopsy using the OSNA assay between 2009 and 2012. The cut-off values of the OSNA assay for negative/positive results and micro/macrometastasis were defined at 250 and 5,000 copies/μL of cytokeratin 19 mRNA, respectively. In the SN-positive patients, all paraffin blocks containing the primary tumor were step-sectioned with 0.5-mm intervals until the tissue was exhausted, and all microscopic slides were examined for detecting occult invasions. Afterwards, the patients were classified into three cohorts based on the SN status and occult invasion: (1) no SN metastasis (TisN0), (2) SN metastasis without occult invasion (TisN1), and (3) SN metastasis with occult invasion (T1N1). Tumor characteristics including risk factors of occult invasions (e.g. large size, comedo-type), prognosis, and SN and non-SN status were compared among the three cohorts. The median follow-up time was 73.6 months.

Results: Of the 427 patients, 408 (95.6%) were SN-negative and 19 (4.4%) were SN-positive. By examining a total of 1,421 step-sectioned slides, 9 of the 19 SN-positive patients had occult invasions in the primary tumors. Overall, 408 (95.6%), 10 (2.3%), and 9 (2.1%) were classified into the TisN0, TisN1, and T1N1 cohorts, respectively. Either of adjuvant endocrine therapy or chemotherapy was given much more in the TisN1 and T1N1 cohorts than in the TisN0 cohort (80.0% and 88.9% vs. 5.4%).Other tumor characteristics were similar among the three cohorts. Although one patients had distant recurrence in the TisN0 cohort, none had locoregional or distant recurrences in the TisN1 and T1N1 cohorts. Regarding the lymph node status in the TisN1 and T1N1 cohorts, median tumor burdens in the SN are 590 and 310 copies/μL, and 2 (20.0%) and 2 (22.2%) patients had additional non-SN metastasis in the axillary dissection materials, respectively.

Conclusions: Tumor characteristics and prognosis were similar among the three cohorts albeit the TisN1 and T1N1 cohorts tended to received adjuvant systemic therapy. Moreover, the SN and non-SN status were similar between the TisN1 and T1N1 cohorts. Therefore, pathogenesis of nodal metastasis in DCIS cannot uniformly be explained, and tumors with different stages may be mixed in the node-positive DCIS. Thus, considering the favorable prognosis of node-positive DCIS, the clinical management should be determined on a case-by-case basis.

Citation Format: Yonekura R, Osako T, Iwase T, Ogiya A, Ueno T, Ohno S, Akiyama F. Prognostic impact and possible pathogenesis of lymph node metastasis in ductal carcinoma in situof the breast [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-11.

Abstract P3-03-23: Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes

Background: Axillary lymph node status is one of the most powerful prognostic factors in breast cancer. However, it remains unknown which factor of metastatic lymph nodes–the number, tumor volume or anatomical location–is independently prognostic. Conventional pathological examinations of lymph nodes have limited ability to accurately measure metastatic tumor volume due to the partial evaluation of nodes. On the other hand, the one-step nucleic acid amplification (OSNA) assay, a novel molecular method, can quantify the tumor volume in a whole node based on cytokeratin 19 (CK19) mRNA copy number. In this prospective cohort studyusing the OSNA whole-node analysis, we aimed to elucidate the independent prognostic factor of lymph node metastasis in breast cancer.

Patients and Methods: The subjects consisted of 307 cN0 patients with invasive breast cancer, who underwent axillary dissection after a metastatic sentinel node (SN) biopsy and whose SNs and non-SNs were all examined using the OSNA whole-node assaybetween 2009 and 2012.The cut-off values of the OSNA assay for negative/positive results and micro/macrometastasis were defined at 250 and 5,000 copies/μL of CK19 mRNA, respectively. The total tumor volume in the SN or non-SN was defined as the sum of CK19 mRNA copy numbers from all samples in the SN or non-SN. The cut-off value for the total tumor volume in the SN was set at 2,810 copies/μL according to our previous study (Osako et al. Br J Cancer 2017). The anatomical location of metastasis was classified into Level I (confined to SN), Level I (spread to non-SN), or Level II/III. Predictive factors for distant disease-free survival (DDFS) were investigated using the univariate log-rank tests and multivariate Cox proportional hazards models.The median follow-up time was 6.1 years (range, 0.2–8.6).

Results: Of the 307 patients, 130 (42.3%) and 177 (57.7%) had the total tumor volume &lt;2,810 and ≥2,810 copies/μL in the SN, respectively. Five-year DDFS was 96.0% in the entire cohort. In the univariate analysis, DDFS was significantly related to the pT classification, grade, hormone receptor status, triple-negative subtype, total tumor volume in the SN and cytotoxic chemotherapy. However, DDFS was not significantly related to the number of metastatic or macrometastatic nodes in the SN, non-SN, or all nodes (i.e. SN + non-SN); the total tumor volume in the non-SN or all nodes; the AJCC pN classification; or the anatomical location of metastasis. In the multivariate analysis, the total tumor volume in the SN (&lt;2810 vs. ≥2810 copies/μL, hazard ratio 5.2, 95% confidence interval 1.2–23.2, P=0.03) and cytotoxic chemotherapy (- vs. +, hazard ratio 0.05, 95% confidence interval 0.02–0.17, P&lt;0.001) remained significant.

Conclusions: The total tumor volume in the SN was the independent prognostic factor of lymph node metastasis in SN-positive invasive breast cancer. Accurate evaluation of metastatic tumor burden in the SN can be important for predicting prognosis and may help to guide the precise therapeutic decision making for breast cancer patients.

Citation Format: Osako T, Iwase T, Ushijima M, Ogiya A, Ueno T, Ohno S, Akiyama F. Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-23.

Abstract P5-05-04: Myc as a poor prognostic marker for ER+ inflammatory breast cancer (IBC): Quantitative estrogen receptor (ER) expression analysis and gene expression analysis in ER+ IBC vs non-IBC

Background

Estrogen receptor-positive (ER+) primary inflammatory breast cancer (IBC) has a poorer prognosis than ER+ primary non-IBC. Our objective was to determine the association between ER positivity and survival outcome in order to elucidate the biological reason that ER+ IBC is more aggressive than non-IBC.

Methods

We retrospectively determined the relationship between ER expression by immunohistochemistry staining and neoadjuvant chemotherapy response as well as survival outcome for 189 patients with ER+ and HER2-negative (HER2-) IBC and 896 case-matched patients with stage III non-IBC seen at MD Anderson Cancer Center between January 1989 and April 2015. We performed gene expression (GE) analysis for 39 patients with ER+/HER2- IBC and 40 patients with non-IBC to detect genes that are specifically overexpressed in IBC. Logistic regression and Cox proportional hazards model were used to determine the predictive and prognostic value of percentages of cells positive for ER and progesterone receptor (PR) among the patients with ER+/HER2- IBC and non-IBC. Recursive partitioning analysis (RPA) was used to determine the optimal cutoff points for ER% and progesterone receptor (PR) % that maximized differences in survival. The identified cutoff points were tested in an external cohort of 192 ER+/HER2- IBC patients from Institut Paoli-Calmettes in France.

Results

The median values for ER% for IBC and non-IBC were 85 (range, 1-100) and 90 (range, 1-100), respectively. The logistic regression model demonstrated a lack of a relationship of ER% with pathological complete response rate to neoadjuvant chemotherapy both in IBC (P=0.29) and non-IBC (P=0.14). Expression of ER was significantly associated with distant disease-free survival (DDFS); hazard ratio (HR), 0.56 [95% CI, 0.37-0.83] per 50% increase in ER%; P&lt;0.05). Also, ER% was significantly associated with overall survival (OS) (HR, 0.40 [95% CI, 0.25-0.63] per 50% increase in ER%; P&lt;0.05). RPA showed that 91.5% and 9.0% were the optimal cutoff points for ER% and PR%, respectively, for DDFS and overall survival in IBC patients. However, the cutoff points could not be validated in the French external cohort. In the GE study, 84 genes were detected as significantly distinguishing ER+ IBC from non-IBC. Among the top 15 canonical pathways shown by IPA, the ERK/MAPK signaling pathway, PDGF pathway, insulin receptor signaling pathway, and IL-7 signaling pathway were associated with the ER signaling pathway. MYC upregulation was observed in three of these four pathways. Indeed, ER+/HER- IBC had significantly higher MYC amplification compared to those with non-IBC (P&lt;0.05) and higher MYC level was associated with poor relapse free survival for IBC (HR, 1.85 [95% CI, 1.05-2.70], P&lt;0.05).

Conclusions

Increased ER positivity was significantly associated with improved survival in ER+/HER- IBC patients. ER+/HER- IBC had several activated pathways with MYC upregulation compared to non-IBC. MYC upregulation was associated with a poor survival outcome for ER+/HER- IBC. The results indicate that MYC is a key gene for understanding the aggressive biological behavior of ER+/HER- IBC.

Citation Format: Iwase T, Harano K, Masuda H, Kida K, Espinosa Fernandez JR, Hess KR, Wang Y, Woodward WA, Layman RM, Dirix L, Van Laere SJ, Bertucci F, Ueno NT. Myc as a poor prognostic marker for ER+ inflammatory breast cancer (IBC): Quantitative estrogen receptor (ER) expression analysis and gene expression analysis in ER+ IBC vs non-IBC [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-05-04.

Impact of change in body mass index during neoadjuvant chemotherapy and survival among breast cancer subtypes

PURPOSE

We hypothesized that an increase in BMI category during neoadjuvant chemotherapy (NAC) would be associated with pathological complete response (pCR) rate and worse survival outcomes in primary breast cancer patients.

METHODS

We reviewed the records of 4029 patients with stage I-III breast cancer who had undergone NAC and definitive surgery at our institution between May 1, 1990 and April 30, 2013. BMI values at baseline and after NAC were recorded, and the corresponding BMI category was assessed with the WHO classification. Overall survival (OS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier method, and multivariate Cox regression models were used to estimate the effect of covariates of interest on OS and RFS.

RESULTS

The median follow-up period was 3.95 years. A change in BMI category from normal to obese during NAC was independently associated with shorter OS duration than was maintaining a normal weight [hazard ratio (HR) 1.637; 95%CI 1.066-2.514; p = 0.0242]. Kaplan-Meier curves among breast cancer subtypes showed differences, and a decrease in BMI led to better RFS and OS rates in obese patients with HR+/HER2- disease; those who maintained BMI also showed better prognosis for triple-negative breast cancer (TNBC). We saw no association between BMI change and pCR rate.

CONCLUSION

Our data suggest that inability to maintain normal weight during NAC is a predictive marker of poor survival but not pCR. It may be important for patients to maintain a normal weight during NAC.

Abstract P1-07-23: The quality and quantity of visceral fat tissue are associated with insulin resistance and survival outcome after chemotherapy for patients with early-stage breast cancer

Background: Obesity and insulin resistance are associated with inferior levels of chemosensitivity and overall prognosis for breast cancer (BC) treatment. Recent studies suggest that the quality and quantity of visceral adipose tissue (VAT) play a significant role in adipocyte function, and are related to insulin resistance. We therefore tested the hypothesis that high amount and low quality of VAT worsen treatment outcomes via insulin resistance mechanisms.

Patients and Methods: We examined two independent studies: a cross-sectional study (cohort 1) and a retrospective study (cohort 2). Cohort 1 included 106 women with early-stage BC who were undergoing surgery. Patients with normal weight (17.5&lt; body mass index [BMI, kg/m2] ≤25, n = 53) and overweight/obese patients (BMI &gt;25, n = 53) were selected by a pair-matching method. Insulin resistance was evaluated by HOMA-R: fasting insulin (microU/L) × fasting glucose (nmol/L)/22.5. And insulin-like growth factor (IGF) family including IGF-1 and IGF-binding protein 3 (IGFBP3) were measured before beginning treatment. The amounts of visceral fat (aVAT) was measured by 3-dimensional volumetric software using the stocked computed tomography (CT) imaging data. The quality of VAT was assessed based on the mode value of CT Hounsfield Unit of VAT (VAT-HU) at navel level of CT axial view. The association between the former variables and the quality and quantity of VAT was analyzed. Cohort 2 included 271 patients who received chemotherapy in the neo-adjuvant (NAC) or adjuvant setting. Imaging analysis was performed in the same way, and the association between those values and survival outcome after chemotherapy was analyzed by retrospective chart review.

Results: In cohort 1, aVAT was significantly correlated with serum insulin and HOMA-R levels (Pearson's R 0.44 and 0.42, respectively; P&lt;0.05). On comparing the two groups divided by BMI, the levels of IGF-1 and IGFBP3 were not significantly different between the normal weight and the overweight/obese groups (P = 0.31 and 0.77, respectively). However, the overweight/obese group demonstrated significantly higher HOMA-R (P&lt;0.05). In cohort 2, aVAT was significantly correlated with BMI (P&lt;0.05). In a multivariate analysis, pathological complete responses were not associated with aVAT (P = 0.60). After a median follow-up of 112 months, tertile stratification revealed that the third tertile of aVAT had a significantly shorter distant disease free survival (DDFS) in the NAC setting (p&lt;0.05). When adjusted by covariates in the Cox proportional regression model, aVAT and VAT-HU demonstrated significant contribution to a worsened DDFS ([p&lt;0.05, hazard ratio {HR} 1.39; 95% confidence interval {CI} 1.11 to 1.75] and [p&lt;0.05, HR 1.20, 95% CI 1.01 to 1.43], respectively).

Conclusions: Our study found that high amounts and low quality of VAT worsen treatment outcomes. Furthermore, we found that insulin resistance was related to those two factors. Although further validation is needed, our present work suggests the importance of evaluating the quality and quantity of visceral fat for estimating insulin resistance and treatment outcomes after chemotherapy for patients with early-stage BC.

Citation Format: Iwase T, Sangai T, Nagashima T, Sakakibara M, Fujimoto H, Sawabe Y, Nagashima K, Otsuka M. The quality and quantity of visceral fat tissue are associated with insulin resistance and survival outcome after chemotherapy for patients with early-stage breast cancer [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 P1-07-23.

Phase II study of neoadjuvant anthracycline combined with nanoparticle albumin-bound paclitaxel for human epidermal growth factor receptor 2-negative breast cancer

Neoadjuvant chemotherapy (NAC) with anthracyclines followed by taxane chemotherapy has become the standard treatment for patients with locally advanced, operable breast cancer. Recently, the efficacy of nanoparticle albumin-bound paclitaxel (nab-PTX) for metastatic breast cancer was reported. However, there are still few studies of a neoadjuvant regimen including nab-PTX. Thus, the present phase II study evaluated the efficacy and safety of 5-fluorouracil, epirubicin and cyclophosphamide (FEC regimen) followed by nab-PTX as neoadjuvant treatment for operable human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Women with operable HER2-negative breast cancer (clinical stage T1a-4N1-3) received 4 cycles of FEC (5-fluorouracil 500 mg/m², epirubicin 100 mg/m² and cyclophosphamide 500 mg/m² every 21 days), followed by 4 cycles of nab-PTX at 260 mg/m² every 21 days. The patients then underwent mastectomy or breast-conserving surgery (BCS). The primary endpoint was pathological complete response (pCR) rate. The secondary endpoints included clinical response rate, pathological response rate, BCS rate and safety. A total of 16 patients were evaluated and 3 patients (18%) achieved pCR (1 patient with estrogen receptor-positive cancer and 2 with estrogen receptor-negative cancer). The pCR rate was 12 and 25% in patients with estrogen receptor-positive and -negative cancers, respectively. The clinical response rate was 100% (clinical complete and partial response in 6 and 10 patients, respectively). The BCS rate was 31.25%. Three patients experienced grade 3 neutropenia during FEC therapy, and no grade 3/4 events occurred during nab-PTX therapy. Thus, neoadjuvant therapy with FEC followed by nab-PTX for operable HER2-negative breast cancer was found to be a safe and effective option.

The impact of quality and quantity of visceral fat on survival outcome of early-stage breast cancer patients with prior chemotherapy

584

Background: Obesity not only increases morbidity, but also chemo-resistance of breast cancer (BC). Several studies focusing on body mass index (BMI) of BC patients have been performed; however, a recent report suggested that the quality of visceral adipose tissue (VAT) plays a crucial role in fat cell function. We set out to clarify the effect of quality and quantity of VAT on survival outcome of BC patients who underwent chemotherapy. Methods: From 2,230 patients who underwent treatment for BC at our institution from January 2004 to December 2015, we included 271 patients who received chemotherapy in neo-adjuvant (NAC) or adjuvant setting. Quantification was performed using computed tomography (CT) 3-dimensional volumetric software and quality of VAT was assessed based on the CT Hounsfield Unit of VAT (VAT-HU) using electrically stocked CT images. The correlation between BMI, amount of VAT (aVAT), and VAT-HU were analyzed using Pearson’s correlation test. The effect of these factors on pathologic complete response (pCR) was evaluated using Logistic regression model with the following covariates: menopausal status, size, nodal status, and subtype. Furthermore, survival analysis for distant disease-free survival (DDFS) was performed using Kaplan Meier method and Cox proportional hazard model. Results: aVAT and VAT-HU were significantly correlated with patient BMI (p<0.05). Forty-six patients achieved pCR (24%). Logistic regression model for pCR showed that aVAT and VAT-HU did not affect pCR (p=0.60 and 0.36). After a median follow-up of 112 months, tertile stratification revealed that the third tertile of aVAT had significantly shorter DDFS in the NAC setting (p<0.05). When adjusted by covariates in the Cox proportional regression model, aVAT and VAT-HU demonstrated significant contribution to worse DDFS ([p<0.05, hazard ratio {HR} 1.39; 95% confidence interval {CI} 1.11 to 1.75] and [p<0.05, HR 1.20, 95% CI 1.01 to 1.43], respectively). Conclusions: The quantity and quality of VAT was significantly related to the survival outcome especially in the NAC setting. This new insight would enable prediction of recurrence risk in obese BC patients with prior chemotherapy.

An increased neutrophil-to-lymphocyte ratio predicts poorer survival following recurrence for patients with breast cancer

The aim of the present study was to evaluate the association between changes in the neutrophil-to-lymphocyte ratio and the survival rate, as well as tumor subtype, in recurrent breast cancer. Patients with recurrent breast cancer following surgery were included in this study. NLR was calculated and compared between two time points: Pre-treatment and recurrence. The associations between the longitudinal NLR change, the NLR at the time of recurrence and overall survival following recurrence (OSrec) were evaluated. A total of 89 patients were evaluated. NLR increased by 0.59 at recurrence, as compared with the initial treatment (P<0.05). The triple negative (TN) type demonstrated 4.59 in NLR, which was the highest among the four subtypes at the time of recurrence (P<0.05). The highest change (an increase of 2.0) was observed in TN type cancer (P<0.05). Patients with high NLR upon recurrence demonstrated significantly shorter OSrec rates (P<0.05). On the other hand, patients with an NLR increased by more than a third quartile demonstrated a shorter OSrec rate (P=0.06). When adjusted by covariates, the NLR and tumor subtype were determined to be associated with OSrec (P<0.05). Therefore, an increased NLR predicts survival, even in patients with recurrent breast cancer, and the NLR is potentially useful as an inflammation marker for TN breast cancer.

[Breast-Conserving Surgery Using Real-Time Virtual Sonography in a Breast Cancer Patient Who Received Neoadjuvant Chemotherapy - ACase Report]

We report a case of breast-conserving surgeryusing real-time virtual sonography(RVS)in a breast cancer patient who received neoadjuvant chemotherapy(NAC). The patient was a 63-year-old woman. Ultrasound(US)showed a lobulated 45 ×40×40mm diameter mass in the C area of the right breast. Histological examination found invasive ductal carcinoma that was negative for estrogen and progesterone receptors and for human epidermal growth factor receptor type 2/neu protein expression, and the Ki-67 index was 50%. The patient was diagnosed with breast cancer clinical stage II A(T2N0M0). The basal-like subtype is more sensitive to anthracycline-based NAC than luminal breast cancers. The patient wanted breastconserving surgery. Therefore, we treated the patient with NAC. First, we obtained US volume data of the tumor as a Digital Imaging and Communication in Medicine(DICOM)file, simplyscanning the skin over the lesion gentlywith the probe. We administered tri-weeklynanoparticle albumin-bound paclitaxel(nab PTX)followed bya fluorouracil, epirubicin, and cyclophosphamide( FEC)regimen. Follow-up computed tomography(CT)and US showed good tumor concentric shrinkage without anysurrounding lesion after NAC. Finally, right breast-conserving surgerywas performed, using RVS to detect the area where the tumor was before NAC in the US image after NAC. Histopathologically, the effect of the chemotherapy was Grade 2a and the surgical margins were negative.