Cases Of Metastatic Breast Cancer Research Articles

Abstract PO1-16-12: The McPeak-Sirois Group Breast Metastases Registry

Abstract Background: In 2020, the McPeak-Sirois Group (MPSG), a Quebec-based breast cancer trials consortium, launched a feasibility pilot project to register prospectively cases of metastatic breast cancer (MBC). This Breast Metastases Registry (BMR) had the following objectives: a) to measure real-world progression-free and overall survival; b) to capture real-world evidence in efficacy of novel therapeutic approaches and c) to facilitate the development of clinical research projects in MBC. Methods: The pilot phase was initiated in three major academic hospitals with the intention of testing the feasibility of building a BMR and to assess barriers before extension to other hospitals in the province of Quebec. Funding was obtained through non-profit organizations and the pharmaceutical industry. The project was approved by a research ethics board and informed consent was obtained from each patient. The main inclusion criteria was a MBC diagnosis at the time of enrolment. Metastatic diseases were considered de novo if the metastatic condition was detected at the same time of the primary disease diagnosis or within the following 4 months. The information in the BMR relates to participants’ health status, including but not limited to hospitalizations, diagnoses, medications, medical procedures and imaging, pathology, genetic and laboratory results. In addition to the prospective data, the registry also captures information retrospective to the date of enrollment. Results: Between July 30, 2021 and April 22, 2023, a total of 427 patients were approached by a research nurse and 423 patients enrolled and 4 refused (99.2% participation rate). Approximately one third of the cohort was diagnosed between 2021-2023 (30.3%) while 69.7% were in 2002-2020 timeframe. The majority was either HR+/HER2- (55.3%) or HER2+ (26.9%). The median age at the time of MBC diagnosis was 57 years (Q1-Q3 range: 47-67 years). We observed that 57.9% of patients had a relapsed MBC while de novo MBC comprised 42.1% of the cohort with the highest percentage in the HER2+ group (59.6%). The median time between primary cancer and metastatic disease in those with relapsed MBC is shorter in triple negative breast cancer (28.9 months) compared to 71.4 months in HR+ disease. Among all lines of treatment for metastatic disease, independently of age at time of MBC diagnosis, 21% of patients participated in a clinical trial. Discussion: The pilot project demonstrated the acceptability and feasibility of building a MBC provincial registry as illustrated by the high participation rate (more than 99%). The next step is to expand the registry to other hospital sites in Quebec, however, the main difficulty is having the necessary manpower (oncology registrars) to ensure data entry. Over one third of the MBC patients presented as de novo disease (and more than half of these with HER2+ disease). This proportion of de novo MBC is unusually high and is likely due to a recruitment bias during the pilot phase as data entry was prioritised for de novo diagnoses over MBC at time of recurrence and patients were recruited at any time in their MBC trajectory and not only at the time of their MBC diagnosis. Clinical trial participation was higher in our cohort compared to the usually reported 5% participation rate. This may be due to recruitment bias but needs to be evaluated further. Conclusion: We have found that recruiting patients in a metastatic cancer registry and collecting their real-world data is not only feasible but well received by patients. The limiting factor for expansion to other hospitals is lack of oncology registrars. At maturity, the BMR will be a unique and powerful resource for breast cancer research and will allow researchers and their collaborators to unite their efforts to better understand how stage IV breast cancer is treated and how management of the disease can be improved. The BMR could also have the potential to improve participation in clinical trials and to stimulate clinical research. Citation Format: Julie Lemieux, Danielle Charpentier, Dominique Johnson, Nathalie Bolduc, Caty Blanchette, Claude Nadon, Sarkis Meterissian. The McPeak-Sirois Group Breast Metastases Registry [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-16-12.

Abstract PO5-24-06: Genomic findings in metastatic breast cancer

Abstract Introduction: Although metastatic breast cancer is the second leading cause of cancer death in women, the genomic findings in metastatic breast cancer are not as well characterized as those of primary breast cancers. Metastatic tumors are genetically heterogenous, enriched for resistance mutations, and often lack targetable alterations. Improved understanding of the molecular mechanisms that drive metastatic disease of all receptor subtypes is required to identify possible molecular targets and to develop new targeted therapies in an effort to reduce the mortality. Methods: A cohort of 50 metastatic breast cancer cases (n=33 ER+/PR+, n=3 ER+/HER2+, n=3 ER-/HER2+ n=11 TNBC) sequenced at our medical center between 2018-2023 was evaluated, and the molecular findings of the major subtypes were analyzed. Genomic data included mutations, copy number alterations, tumor mutation burden and microsatellite instability. Results: The most frequent somatic alteration were PIK3CA mutations, involving 17/33 of ER+/PR+/HER- tumors, 5/11 TNBC tumors and 5/6 HER+ cases. TP53 mutations (frameshift and missense) were more frequently identified in TNBC and HER2+ cases (p< 0.05). Recurrent CCND1, FGFR1 and MYC copy number amplifications were seen almost exclusively in hormone receptor positive/HER2- tumors (p >0.05). ESR1 mutations involved 15% of the ER positive cancers and were frequently associated with co-occurring CCND1 and FGFR1 copy number gains. Significant genomic losses that drive tumorigenesis were also detected. Both CDKN2a and PTEN deletions were found in ER/PR positive disease, as well as triple negative tumors. Genomic deletions associated with worse outcomes such as TP53 and DICER1 were also detected. ERBB2 amplification was 100% concordant with our immunohistochemical and FISH results for the 6 HER2 positive cases. All 50 cases demonstrated a low tumor mutation burden and were microsatellite stable. Conclusion: We detected driver alterations that involve multiple pathways including estrogen receptor signaling, PI3K/AKT/MTOR, the cell cycle, and receptor tyrosine kinases. The genomic alterations are enriched for resistance mechanisms, like ESR1 mutations and FGFR1 gains that mediate resistance to endocrine treatment, as well as PIK3CA, also implicated in both endocrine and HER2-targeting therapy resistance. Of particular interest, were the amplifications detected in the ER+/PR+ tumors, such as CCND1 on chromosome 11q, FGFR1 on 8p and MYC on 8q, which were detected in almost half (45%) of our hormone receptor positive cohort. Some of the identified driver amplifications also define a subset of the Integrated Molecular Subtypes (Curtis et al., Nature; 486(7403): 346–352), i.e., Clusters 2, 6 and 9 that are typically hormone receptor positive but associated with either a very poor prognosis (Cluster 2) or an intermediate prognosis (Clusters 6 and 9), unlike the copy neutral ER positive tumors or those with the classic 1p and 16q alterations. Therefore, copy number profiling of advanced-stage breast cancers may be a useful tool for determining prognosis, identifying possible targetable driver pathways and selecting appropriate patients for molecularly guided clinical trials. Citation Format: Kimberly Cole, Melissa Tjota, Jeremy Segal, Peng Wang, Susanne Crespo-Ramos. Genomic findings in metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-24-06.

Cyclin-dependent kinase 4/6 inhibitors in the treatment of advanced or metastatic breast cancer.

Despite the relatively high cure rates in early-stage breast cancer, advanced and metastatic breast cancer cases are associated with more inauspicious patient outcomes. Fortunately, with the advent of cyclin-dependent kinase (CDK)4/6 inhibitors (e.g. palbociclib, ribociclib, and abemaciclib) with endocrine therapy, survival in advanced and metastatic breast cancer has appreciably improved. In the current review, we discuss these distinctions and the concomitant implications associated with the individual CDK4/6 inhibitors. We conducted an extensive PubMed search comprising several review articles on the topic of advanced or metastatic breast cancer treatment, with specific terms that included CDK4/6 inhibitors, treatment, and breast cancer. Palbociclib, ribociclib, and abemaciclib have exhibited superior progression-free survival differences compared to endocrine therapy alone. However, there are differences among the various CDK4/6 inhibitors with regard to overall survival, tolerability and quality of life. Ribociclib may be indicated for pre/perimenopausal patients, whereas abemaciclib is potentially recommended to address endocrine-resistant or visceral disease. Alternatively, palbociclib is associated with lower discontinuation rates than abemaciclib and unlike ribociclib, QTc prolongation is not observed with palbociclib.

Association of Mediterranean diet with survival after breast cancer diagnosis in women from nine European countries: results from the EPIC cohort study

BackgroundThe Mediterranean diet has been associated with lower risk of breast cancer (BC) but evidence from prospective studies on the role of Mediterranean diet on BC survival remains sparse and conflicting. We aimed to investigate whether adherence to Mediterranean diet prior to diagnosis is associated with overall and BC-specific mortality.MethodsA total of 13,270 incident breast cancer cases were identified from an initial sample of 318,686 women in 9 countries from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Adherence to Mediterranean diet was estimated through the adapted relative Mediterranean diet (arMED), a 16-point score that includes 8 key components of the Mediterranean diet and excludes alcohol. The degree of adherence to arMED was classified as low (score 0–5), medium (score 6–8), and high (score 9–16). Multivariable Cox proportional hazards models were used to analyze the association between the arMED score and overall mortality, and Fine-Gray competing risks models were applied for BC-specific mortality.ResultsAfter a mean follow-up of 8.6 years from diagnosis, 2340 women died, including 1475 from breast cancer. Among all BC survivors, low compared to medium adherence to arMED score was associated with a 13% higher risk of all-cause mortality (HR 1.13, 95%CI 1.01–1.26). High compared to medium adherence to arMED showed a non-statistically significant association (HR 0.94; 95% CI 0.84–1.05). With no statistically significant departures from linearity, on a continuous scale, a 3-unit increase in the arMED score was associated with an 8% reduced risk of overall mortality (HR3-unit 0.92, 95% CI: 0.87–0.97). This result sustained when restricted to postmenopausal women and was stronger among metastatic BC cases (HR3-unit 0.81, 95% CI: 0.72–0.91).ConclusionsConsuming a Mediterranean diet before BC diagnosis may improve long-term prognosis, particularly after menopause and in cases of metastatic breast cancer. Well-designed dietary interventions are needed to confirm these findings and define specific dietary recommendations.

IL-6 as a predictor of survival rate in liver metastatic breast cancer patients with Covid-19 infection: A case series

Introduction and importanceBreast cancer is the most common type of cancer in women, with 30 % being metastatic breast cancer. Cancer is known to be a comorbid Covid-19 infection. Interleukin-6 (IL-6) is one of the findings of inflammatory activity due to Covid-19 infection. We report IL-6 levels as a prognostic factor for survival rate in patients with liver metastatic breast cancer. Case presentationWe report five cases of liver metastatic breast cancer with various types of primary breast cancer. All patients are infected with Covid-19. IL-6 levels were reported to be elevated in all five patients. All patients were treated according to the national guidelines for the care of Covid-19 patients. All patients are reported to have deceased after being treated for Covid-19 infection. Clinical discussionMetastatic breast cancer has a low prognostic rate. Cancer has been recognized as one of the comorbidities and increases the severity and mortality of Covid-19 infection. Elevated levels of IL-6 are caused by an immune response to infection, and can worsen the outcome of breast cancer patients. Changes in IL-6 levels implicate the survival rate of metastatic breast cancer patients and outcomes during the treatment of Covid-19 infection. ConclusionElevated levels of IL-6 can be a prognostic factor of the survival rate of metastatic breast cancer patients during the treatment of Covid-19 infection.

Genomic landscape of metastatic breast cancer (MBC) patients with methylthioadenosine phosphorylase (MTAP) loss

Homozygous deletion of MTAP upregulates de novo synthesis of purine (DNSP) and increases the proliferation of neoplastic cells. This increases the sensitivity of breast cancer cells to DNSP inhibitors such as methotrexate, L-alanosine and pemetrexed. 7,301 cases of MBC underwent hybrid-capture based comprehensive genomic profiling (CGP). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Tumor cell PD-L1 expression was determined by IHC (Dako 22C3). 208 (2.84%) of MBC featured MTAP loss. MTAP loss patients were younger (p = 0.002) and were more frequently ER- (30% vs. 50%; p < 0.0001), triple negative (TNBC) (47% vs. 27%; p < 0.0001) and less frequently HER2+ (2% vs. 8%; p = 0.0001) than MTAP intact MBC. Lobular histology and CDH1 mutations were more frequent in MTAP intact (14%) than MTAP loss MBC (p < 0.0001). CDKN2A (100%) and CDKN2B (97%) loss (9p21 co-deletion) were significantly associated with MTAP loss (p < 0.0001). Likely associated with the increased TNBC cases, BRCA1 mutation was also more frequent in MTAP loss MBC (10% vs. 4%; p < 0.0001). As for immune checkpoint inhibitors biomarkers, higher TMB >20 mut/Mb levels in the MTAP intact MBC (p < 0.0001) and higher PD-L1 low expression (1-49% TPS) in the MTAP loss MTAP (p = 0.002) were observed. MTAP loss in MBC has distinct clinical features with genomic alterations (GA) affecting both targeted and immunotherapies. Further efforts are necessary to identify alternative means of targeting PRMT5 and MTA2 in MTAP-ve cancers to benefit from the high-MTA environment of MTAP-deficient cancers.

Abstract P5-14-09: Comparison of cell-free DNA genomics of breast cancer associated-chest wall disease vs. age &amp; subtype matched controls with metastatic breast cancer not involving the chest wall

Abstract Background: Breast cancer associated-chest wall disease (CWD) clinically behaves in an aggressive manner. However, little is known about the genomics of CWD. Cell-free DNA (cfDNA) can identify oncogenic mutations in metastatic breast cancer (MBC). We hypothesized that the cfDNA genomics of CWD may vary from MBC cases without CWD. We compared the cfDNA genomics of patients with CWD to that of age and subtype matched MBC controls without CWD. Methods: Patients with MBC at an academic institution who underwent cfDNA testing (Guardant360, next generation sequencing (NGS), 74 gene assay) from 2/2016-2/2021 were identified. Patients with documented CWD (chest wall recurrence with nodules, ulceration, and/or skin metastases on imaging and/or examination) at the time of cfDNA testing (coinciding with MBC diagnosis) were included in the CWD cohort. Age and subtype matched MBC controls without CWD (CON) during the same time period with cfDNA results at MBC diagnosis were identified. A retrospective review was conducted to determine clinical features and cfDNA genomics of CWD and CON. A two-sample test of proportions was used to compare CWD to CON, with p&amp;lt; 0.05 for statistical significance. Results: Thirty-one patients with CWD and 63 CON were identified. Both groups were well-matched in median age at MBC diagnosis (CWD 57 vs. CON 59 years, p=0.93) and subtype distribution (CWD: TNBC 35%, HR+/HER2- 58%, HER2+ 6%; CON: TNBC 29%, HR+/HER2- 65%, HER2+ 6%, p=0.78). Patients also had similar racial distribution in both cohorts (p=0.57). Ninety percent (28/31) of CWD vs. 90% (57/63) of CON had ≥1 mutation detectable in cfDNA (p=0.62). Median number of cfDNA mutations for CWD was 4.5 (range 0-16) vs. 4 (range 0-21) in CON (p=0.32). The most common cfDNA mutations in CWD were TP53 (58%), NOTCH1 (19%), PIK3CA (16%), BRCA1 (13%), NF1 (13%), FGFR2 (13%), ESR1 (13%), STK11 (10%), NTRK1 (10%), APC (10%), and KIT (10%). In comparison, the most common cfDNA mutations in CON were TP53 (54%), PIK3CA (35%), ESR1 (14%), GATA3 (13%), and ATM (11%). Table 1 depicts mutations that varied between CWD and CON which were statistically significant in ≥1 cohort analyzed. In HR+/HER2- MBC, NOTCH1, STK11, NTRK1, DDR2, and NF1 were significantly more common in CWD than CON. For TNBC, NOTCH1 was numerically more common in CWD vs. CON (p=0.06). Conclusions: The cfDNA genomic spectrum of CWD varies from MBC that does not infiltrate the chest wall. Mutations that are associated with metastasis (NOTCH1), inhibition of tumor suppression (STK11), tumor migration (DDR2), proliferation (NTRK1), and endocrine resistance (NF1) were significantly more common in HR+/HER2- CWD than matched controls. Further research is needed to validate these findings and determine the impact of matched targeted therapies for CWD. Table 1 N/A: mutation not observed Citation Format: Neelima Vidula, Lianne Ryan, Andrzej Niemierko, Dejan Juric, Steven J. Isakoff, Francys Verdial, Marjan Azin, Laura A. Petrillo, Beverly Moy, Leif Ellisen, Shadmehr Demehri, Aditya Bardia. Comparison of cell-free DNA genomics of breast cancer associated-chest wall disease vs. age &amp; subtype matched controls with metastatic breast cancer not involving the chest wall [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 P5-14-09.

Abstract P2-09-03: Quantification of HER2 expression and spatial biology using computational pathology: A cross-assay validation study in breast cancer

Abstract Background Conventional pathologic scoring of HER2 by IHC is proven to distinguish potential responders to trastuzumab but has not been effective for next generation antibody drug conjugates (ADCs) such as trastuzumab deruxtecan (T-DXd), which is capable of bystander killing. Several alternative approaches have been deployed to measure HER2, including immunofluorescence and mRNA sequencing. We have developed a novel and fully automated computational pathology technique, Quantitative Continuous Scoring (QCS), to quantify the level and distribution of HER2 from digitized HER2 IHC slides in an objective, quantifiable, and reproducible manner on a per-cell basis [Gustavson et al., SABCS 2020]. To further validate this approach, we performed a systematic multi-omic comparison of QCS to orthogonal methods of HER2 quantitation on a cohort of primary and metastatic breast cancer cases (N=30). Methods HER2 was evaluated using three independent methods on serial tissue sections obtained from 30 archival FFPE breast cancer samples distributed over the full range of HER2 expression, from 0 to 3+. HER2-IHC staining (clone 4B5, Roche Tissue Diagnostics) was performed using standard methods and cases were scored by two pathologists using CAP/ASCO guidelines and H-scores were assigned. We performed FISH (HER2 IQFISH pharmDx [Dako]; PathVysion HER-2 DNA Probe Kit [Vysis]), mRNA quantification of ERBB2 transcript levels (Nano String), and immunofluorescence (IF; HER2 clone 29D8, CST). Imaged with Vectra (Akoya) and analyzed with Halo (Indica). QCS readouts were generated from the above-mentioned digital images of IHC slides by using a fully automated image analysis pipeline; readouts included per-cell staining intensity measurements of membranes and cytoplasmic sub-compartments in terms of optical density (OD) [Van der Laak, JQCS 2000], which were aggregated to a single slide-level score. Additionally, using the OD measurements and the cell locations, a Spatial Proximity Score (SPS) was computed, summing the percentage of cells with OD≥10 (corresponding to the limit of visual detection of IHC staining) as well as the percentage of cells with OD&amp;lt; 10 within a prespecified radius (25µm) of a neighboring cell with OD≥10. Results Our analysis demonstrated that QCS-based scoring correlates with orthogonal measurements used in this study. Comparing protein-based assays, the observed Pearson correlation was R=0.88 between QCS median membrane OD and IHC H-scores, R=0.86 with IF-based HER2 mean cell expression intensity, and R=0.85 with IF-based H-scores. Correlation with transcriptomic profiling was R=0.81 for OD vs. mRNA, however ERBB2 transcript levels did not distinguish between HER2 0, 1+, and 2+ FISH negative cases, while QCS was able to do so. Correlation between protein-based and nucleic-acid based assays were numerically worse, with R=0.64 for OD vs. FISH. All samples (including those with HER2 IHC scores of 0 and H-Scores &amp;lt; 10) had at least ~20% of cells with quantifiable HER2 expression by OD, the presence of which was confirmed using IF. For cases in the lowest quartile of HER2 expression by OD, SPS identified 20-50% additional HER2-null cells that were in close proximity to HER2-expressing cells that may be vulnerable to bystander killing. Conclusion QCS-based scoring is consistent with orthogonal protein-based measurements across the range of HER2 expression. Most importantly, QCS derived-spatial analysis features identify additional patients in the lower end of HER2 expression that might be highly relevant for ADC response prediction, particularly if a drug exerts bystander activity. Further clinical verification and validation on large cohorts is needed. Footnote: This study was approved by the IRB at MSKCC. Citation Format: Joshua Drago, Zonera Hassan, Jan Zaucha, Ansh Kapil, Fatemeh Derakhshan, Fresia Pareja, Shimulov Anatoliy, Fanni Ratzon, Travis J Hollman, Claire Myers, Jessica Chan, Andrea Spitzmuller, Mark Gustavson, Danielle Carroll, Dara Ross, Jorge Reis-Filho, Carl barrett, Sihem Khalifa, Schmidt Guenter, Hadassah Sade, Sarat Chandarlapaty. Quantification of HER2 expression and spatial biology using computational pathology: A cross-assay validation study in 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 P2-09-03.

Abstract P2-11-06: Plasma assay of methylated DNA markers (MDM) detects patients with metastatic breast cancer (MBC) compared to healthy controls and treated breast cancer patients with no evidence of disease

Abstract Objective: Aberrantly methylated DNA may be used to detect minimal residual disease or early recurrence in breast cancer. As a 1st step, we aimed to develop an MDM panel to delineate between healthy women, stage I-III breast cancer in remission with no evidence of disease (NED), and metastatic breast cancer (MBC). Methods: We prospectively enrolled patients into 3 groups: healthy controls (adult females with a normal mammogram in past 12 months with no history of breast cancer), NED [stage I-III breast cancer with no clinical evidence of recurrence 6 months - 3 years post-treatment (adjuvant endocrine therapy allowed)], and MBC (collected either at initial diagnosis of untreated metastatic disease or radiographic progression). DNA was extracted from 6 mL of plasma derived from blood collected in LBgard tubes (Exact Sciences Corp., San Diego CA), and was bisulfite-treated and assayed by target enrichment long-probe quantitative amplified signal (TELQASTM) method for a panel of 15 previously identified MDMs [Table], normalized by the control gene, B3GALT6. Areas under the receiver operating characteristic curve (AUC) were calculated for each MDM to assess discrimination of MBC from other groups. With 60 patients per group, we had greater than 80% power to detect a difference of 0.20 from the null AUC of 0.7. Results: We tested samples from 60 MBC (10 untreated, 50 recurrent), 60 NED, and 60 healthy women. The median age was 63 (IQR, 55-72) and was not different between groups. The NED group was all hormone-receptor (HR) positive, with 47 (78%) being human epidermal growth factor receptor 2 negative (HER2-) and 13 (22%) HER2+; 48 (80%) were stage I and 9 (15%) were N+. The MBC group had 35 (58%) patients with HR+/HER2- tumors, 11 (18%) HR+/HER2+, and 6 (10%) HR-/HER2-, 4 (7%) HR-/HER2+, with 4 (7%) unknown. Of the 41 MBC whose original stage and nodal status were known 9 (22%) were stage I and 22 (54%) were N+. The markers were able to discriminate between MBC and NED patient samples with AUCs from 0.97 to 0.72. AUCs for 10/15 MDMs (ITPRIPL1, EMX1, C17orf64, OSR2, TRIM67, CHST2, IFFO1, TRH, FAM59B, and MPZ) were &amp;gt;0.90. No difference in MDMs was observed between the healthy and NED groups. Conclusions: MDMs, assayed from plasma, appear highly discriminant for metastatic breast cancer cases in comparison to control patients with NED or healthy controls. Further clinical validation of this MDM panel in a larger cohort is warranted. Table 1. Plasma MDM discrimination of metastatic breast cancer (MBC) from healthy controls and previously treated breast cancer patients with no evidence of disease (NED) Citation Format: Karthik V. Giridhar, Fergus J. Couch, Jason P. Sinnwell, Seth W. Slettedahl, William R. Taylor, Douglas W. Mahoney, Patrick H. Foote, Maria C. O’Connell, Mariah J. Robran, Mary E. Devens, Anna M. Gonser, Nicole Larson, Karen A. Doering, Kelli N. Burger, Michael Kaiser, Hatim Allawi, Kathryn Ruddy, Janet Olson, John B. Kisiel. Plasma assay of methylated DNA markers (MDM) detects patients with metastatic breast cancer (MBC) compared to healthy controls and treated breast cancer patients with no evidence of disease [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 P2-11-06.

CDK4/6 Inhibitors Overcome Endocrine ESR1 Mutation-Related Resistance in Metastatic Breast Cancer Patients

ESR1 mutations contribute to endocrine resistance and occur in a high percentage of hormone-receptor-positive (HR+) metastatic breast cancer (mBC) cases. Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) changed the treatment landscape of HR+ mBC, as they are able to overcome estrogen resistance. The present retrospective study investigates the clinical benefit of CDK4/6i in ESR1 mutant HR+ mBC patients treated with a CDK4/6i as first- or second-line therapy. Plasma was collected at baseline prior to CDK4/6i plus hormone therapy as a first- or second-line treatment. Circulating free DNA (cfDNA) was extracted from plasma, and ESR1 mutation analysis was performed on a ddPCR. Statistical analyses were performed to investigate the predictive power of ESR1 mutations and any association with clinical factors. A total of 42 patients with mBC treated with CDK4/6i plus endocrine therapy as first- (n = 35) or second-line (n = 7) were enrolled. Twenty-eight patients received hormonal therapy (AI or tamoxifen) in the adjuvant setting. ESR1 mutation status in blood was associated with shorter median disease-free survival (DFS) (30 vs. 110 months; p = 0.006). Multivariate analysis confirmed ESR1 mutations as independent factors of resistance in adjuvant hormone therapy. On the contrary, no difference in progression-free survival (PFS) was observed in the presence or absence of an ESR1 mutation in patients treated with CDK4/6i as first-line treatment (p = 0.29). No statistically significant correlation between the best response to CDK4/6i and ESR1 mutation was found (p = 0.46). This study indicates that the ESR1 mutation detected in cfDNA is an independent predictive factor of clinical recurrence in the adjuvant setting and that CDK4/6i can overcome ESR1-dependent resistance.

Clinical Features and Prognosis of Uncommon Metastatic Breast Cancer: A Retrospective Analysis of 82 Cases.

With the improvement of diagnostic techniques, numerous uncommon metastases derived from breast cancer were reported. However, very few studies explored the clinical characteristics and prognostic patterns of these patients. A total of 82 cases of uncommon metastatic breast cancer (MBC) registered at our hospital from January 1, 2010, to July 1, 2022, were selected for this retrospective study. The diagnoses of uncommon metastases were based on pathology, and the potential prognostic indicators (overall survival [OS], uncommon disease-free interval [uDFI], and remaining survival [RS]) were estimated. The uncommon metastases involved distant soft tissue, parotid gland, thyroid, digestive system, urinary system, reproductive system, bone marrow, and pericardium. Stepwise multivariate Cox regression analysis indicates age ≤ 35 is an independent risk factor of poor outcome of OS, uDFI, and RS in uncommon MBC patients. Meanwhile, uncommon metastasis combined with common visceral metastasis is an independent risk factor for poor RS of uncommon MBC patients, with a hazard ratio of 6.625 (95% confidence interval = 1.490-29.455, P = .013). Post hoc pairwise comparisons showed that uncommon MBC patients who developed bone-only metastasis survived longer than those concomitant with common visceral metastasis (P = .029). Although the incidence is low, uncommon MBC may involve multiple metastatic sites. The delayed diagnosis of uncommon metastases could lead to systemic progression of the disease. However, patients who only develop uncommon metastasis have a significantly better prognosis than that of those combined with common visceral metastasis. Even for those complicated by bone-only metastasis, active treatment of bone metastases can still achieve substantially longer survival.

Radiotherapeutic Strategies to Overcome Resistance of Breast Cancer Brain Metastases by Considering Immunogenic Aspects of Cancer Stem Cells.

Breast cancer is the most diagnosed cancer in women, and symptomatic brain metastases (BCBMs) occur in 15-20% of metastatic breast cancer cases. Despite technological advances in radiation therapy (RT), the prognosis of patients is limited. This has been attributed to radioresistant breast cancer stem cells (BCSCs), among other factors. The aim of this review article is to summarize the evidence of cancer-stem-cell-mediated radioresistance in brain metastases of breast cancer from radiobiologic and radiation oncologic perspectives to allow for the better interpretability of preclinical and clinical evidence and to facilitate its translation into new therapeutic strategies. To this end, the etiology of brain metastasis in breast cancer, its radiotherapeutic treatment options, resistance mechanisms in BCSCs, and effects of molecularly targeted therapies in combination with radiotherapy involving immune checkpoint inhibitors are described and classified. This is considered in the context of the central nervous system (CNS) as a particular metastatic niche involving the blood-brain barrier and the CNS immune system. The compilation of this existing knowledge serves to identify possible synergistic effects between systemic molecularly targeted therapies and ionizing radiation (IR) by considering both BCSCs' relevant resistance mechanisms and effects on normal tissue of the CNS.

Estimated Prevalence of Metastatic Breast Cancer in England, 2016-2021

This case series study provides an estimate of total cases of metastatic breast cancer in England based on National Health Service data.

Clinicopathologic Review of Metastatic Breast Cancer to the Gynecologic Tract.

Metastatic spread is the single most significant predictor of poor survival in breast cancer. Some of the most common metastatic sites are the bones, lungs, liver, brain, and peritoneal cavity. Clinically metastatic breast cancer to the gynecologic tract is usually asymptomatic and diagnosed as an incidental finding during a histologic examination of gynecologic specimens resected for other reasons. Cases of metastatic breast cancer to gynecologic organs diagnosed from August 1995 to January 2021 were retrieved from our institution's pathology databases, and their clinicopathologic features were reviewed. The most common site of metastasis was the ovary which was involved in about 79% (22 of 28 cases) of metastases to the gynecologic tract. Clinically, only 8 cases (36%) presented with ovarian mass detected in imaging studies and the rest of the cases were all incidental findings. Among ovarian metastasis, 59% of cases were invasive lobular carcinoma and 41% were invasive ductal carcinoma. In 5 cases, metastatic breast cancer was found in the endometrium, including 2 cases with endometrial metastasis only and 3 cases with multiple gynecologic organs involved. Metastatic breast cancer rarely involved the lower gynecologic tract, with only 7% vaginal metastasis and 4% found in the vulva. The absolute majority of metastatic breast cancer outside of the ovaries were lobular carcinoma (88%). Most of the metastatic breast carcinomas were positive for estrogen receptor on immunohistochemistry (27 of 28 cases, 96%). Her-2/neu immunostaining was positive in 4 cases only (14%). Metastatic breast cancer needs to be distinguished from gynecologic primary neoplasms and metastatic tumors from adjacent urinary and GI tracts. A careful review of the patient's history and adequate immunohistochemistry panel are helpful to render the diagnosis.

Dual-Energy Computed Tomography for Evaluation of Breast Cancer Follow-Ups: Comparison of Virtual Monoenergetic Images and Iodine-Map.

Differentiating tumor tissue from dense breast tissue can be difficult. Dual-energy CT (DECT) could be suitable for making diagnoses at breast cancer follow-ups. This study investigated the contrast in DECT images and iodine maps for patients with breast cancer being followed-up. Chest CT images captured in 2019 were collected. Five cases of metastatic breast cancer in the lungs were analyzed; the contrast-to-noise ratio (for breast tissue and muscle: CNRb and CNRm, respectively), tumor-to-breast mammary gland ratio (T/B), and tumor-to-muscle ratio (T/M) were calculated. For 84 cases of no metastasis, monochromatic spectral and iodine maps were obtained to compare differences under various breast densities using the K-means algorithm. The optimal T/B, T/M, and CNRb (related to mammary glands) were achieved for the 40-keV image. Conversely, CNRm (related to lungs) was better for higher energy. The optimal balance was achieved at 80 keV. T/B, T/M, and CNR were excellent for iodine maps, particularly for density > 25%. In conclusion, energy of 80 keV is the parameter most suitable for observing the breast and lungs simultaneously by using monochromatic spectral images. Adding iodine mapping can be appropriate when a patient’s breast density is greater than 25%.

Breast Cancer in Italy: Stage and Region Distribution.

PurposeDescribe breast cancer in Italy by age, geographical area, stage and sites of metastases. In addition, incident and prevalent cases by region are provided.Patients and MethodsThis population-based study included all female patients with histologically confirmed breast cancer diagnosed in Italy between 2013 and 2019 in the eight participating Cancer Registries. Cases were described by geographic area (north, center, south), age group (<50, 50–69 and 70+) and site of metastases. In addition, the study also provided an estimate of the cases of metastatic breast cancer per single region.ResultsOf the total 5731 cases, the number of unknown stage cases (eliminated from our analyses) was 545 (10.5% of cases); therefore, the study was conducted on 5186 cases. Overall, 333 (6.5%) of tumors were metastatic at diagnosis but the distribution by geographical area was different: 5.1% in the north, 7.4% in the center and 7.8% in the south. Related to age, 5.6% were diagnosed before the age of 50 and 5.6% within the screening target group (50–69 years), while in elderly women the percentage rose to 8.1%. As regards the site of the metastases, 27.1% developed metastasis to the bone, 12.4% to the liver, 8.6% to the lung and 2.6% to the brain; in 34.9%, multiple sites were already present at the beginning of the cancer. Overall, 3520 cases of incident mBC are estimated in Italia every year (520 in Lombardy in northern Italy, 350 in Lazio in the center, followed by 330 in Campania in the south), and finally they are out of 52,000 prevalent cases.ConclusionA greater possibility of treating and living with the disease for a long time now requires careful monitoring of these tumors.

46. Concordance of immunohistochemistry and fluorescence in situ hybridization in determining HER2 status

Breast cancer is the most commonly diagnosed cancer in females and the most common cause of cancer-related death in women worldwide. Breast cancers that demonstrate amplification of the human epidermal growth factor 2 gene (ERBB2/HER2) are routinely treated with HER2- targeted therapies, which significantly increase survival. Based on current ASCO/CAP guidelines, laboratories may perform IHC first and reflex to FISH when equivocal. At our institution, we perform both IHC and FISH testing to evaluate HER2 status in all newly diagnosed and metastatic breast cancer cases.

S1811 Cecal Ulceration as the Presenting Finding of Metastatic Breast Cancer: A Case Report and Review of Literature

Introduction: Breast cancer is the second most common malignancy worldwide and the second leading cause of cancer mortality in women. Despite routine screening, early detection, and evolving treatment modalities, recurrence and metastatic disease often occur. While breast cancer metastases are traditionally identified in the lung, liver, and bone, metastases to the gastrointestinal tract are rare. Metastases to the stomach are more commonly identified than to the colon and rectum. Prior cases of metastatic breast cancer to the gastrointestinal tract are reported in individuals with an established diagnosis of breast cancer. We describe a case of an ulcerated lesion in the cecum as the initial presenting sign of metastatic primary breast cancer. Case Description/Methods: A 64-year-old-woman with hypertension and chronic constipation was referred to our institution for evaluation of seven weeks of fatigue, one week of urinary symptoms, and lower extremity edema. The patient had undergone ten years of unremarkable screening mammograms. On admission, laboratory workup was notable for markedly elevated liver enzymes. Computerized tomography scan indicated evidence of an ileocecal valve mass and extensive diffuse hepatic metastases. Endoscopic evaluation revealed a benign appearing 30mm sessile polyp in the proximal rectum 15cm from the anal margin and a 3mm ulcer in the cecum (A, B, C, D). Pathologic evaluation and immunohistochemical analysis of the cecal ulceration tissue was suggestive of a diagnosis of primary breast cancer with metastasis to the colon (E, F, G, H).The polyp in the proximal rectum was benign. The patient elected to be discharged to home and had close follow-up. The rapidly progressive nature of the patient’s presentation prevented further workup and ultimately the patient expired less than a month after diagnosis. Discussion: We present an unusual case of metastatic carcinoma of the breast to the colon and liver in an individual without a previous diagnosis of breast cancer who is treatment naïve. The accelerated time course from presentation to patient death was noteworthy. Accurate identification and differentiation between primary gastrointestinal cancer and metastatic breast cancer is paramount to proper management and treatment of the disease. This can be achieved through engaging a multidisciplinary team. This case highlights the need to maintain a high index of suspicion for colon ulcers and lesions as potential sites of metastasis of other primary malignancies such as breast cancer.Figure 1.: A 30mm sessile polyp in the proximal rectum 15cm from the anal margin (A), rectal polyp resected and retrieved (B), and 3mm ulcer in the cecum (C, D). Medium power (40x) and high power (100x) views of a H&E stained slide shows a biopsied fragment of colonic mucosa with metastatic carcinoma involving the deep mucosa and superficial submucosa. The moderately to poorly differentiated malignant epithelial cells infiltrate in nests and cords without forming clear glandular structures (E, F). Nuclear hyperchromasia is seen on higher magnification (F). Immunohistochemical staining, essential in the characterization of this tumor, supports the diagnosis of a carcinoma metastatic from the breast. CK7 shows strong, diffuse positivity, highlighting tumor cells (G). GATA3 shows scattered but strong, nuclear positivity (H). Tumor cells are negative for CK20, CDX2, and S100.

Projecting the Prevalence and Costs of Metastatic Breast Cancer From 2015 through 2030.

BackgroundThis study projected the number of metastatic breast cancer (mBC) cases and costs (medical and productivity) attributable to mBC through 2030 among 3 age groups: younger (aged 18-44 years), midlife (aged 45-64 years), and older women (aged 65 years and older).MethodsWe developed a stock/flow model in which women enter the mBC population at initial diagnosis (de novo stage IV) or through progression of an earlier-stage cancer. Women exit the mBC population through death. Input parameters by age and phase of treatment came from the US Census, Surveillance, Epidemiology, and End Results and peer-reviewed literature.ResultsIn 2030, we estimated there would be 246 194 prevalent cases of mBC, an increase of 54.8% from the 2015 estimate of 158 997. We estimated total costs (medical and productivity) of mBC across all age groups and phases of care were $63.4 billion (95% sensitivity range = $59.4-$67.4 billion) in 2015 and would increase to $152.4 billion (95% sensitivity range = $111.6-$220.4 billion) in 2030, an increase of 140%. Trends in estimated costs were higher for younger and midlife women than for older women.ConclusionsThe cost of mBC could increase substantially in the coming decade, especially among younger and midlife women. Although accounting for trends in incidence, progression, and survival, our model did not attempt to forecast structural changes such as technological innovations in breast cancer treatment and health-care delivery reforms. These findings can motivate early detection activities, direct value-driven mBC treatment, and provide a useful baseline against which to measure the effect of prevention and treatment efforts.

Abstract 586: Expression of CD68 on CKpos/CD45pos circulating cells in breast cancer patients: An additional hint supporting the fusion hybrid theory

Abstract Background: Cells expressing both cytokeratyins (CK) and CD45 (dual-positive, DPcells), circulating in the blood of patients with solid tumors, have been reported for different cancers. Their origin is not clear yet, but one hypothesis is that they are hybrids, deriving from the fusion of tumor cells and macrophages. Recently, we have demonstrated that DPcells can have aberrant genomes, and that, in metastatic breast cancer, they are associated with shorter progression free survival. However, a direct proof of their origin from tumor/macrophage fusion is lacking. Here, we investigated the expression of a macrophage marker (CD68) on DPcells in breast cancer patients. Methods: Blood samples collected from BC patients were analyzed using the CellSearch platform, which allowed for the evaluation of the expression of CK, CD45 and CD68 on circulating cells enriched for EpCAM expression. Based on the marker expression, cells were classified as circulating tumor cells (CTCs, CKpos/CD45neg), and DPcells (CKpos/CD45pos). Results: Twenty-six blood samples were collected from 26 patients with luminal, HER2+, and triple negative BC (n = 13, 5, and 8, respectively). Of these, 6 had non-metastatic (NM) BC (i.e. early breast cancer or locally advanced breast cancer), and 20 had metastatic BC (MBC). Overall, 43 DPcells were identified in 14 (54%) samples (3/6 from NMBC and 11/20 from MBC patients). CD68 expression was detected on 26 DPcells (60%) from 13 samples. In the majority of cases (7/13 samples), CD68pos and CD68neg DPcells were detected together, whereas, in 5 samples, CD68pos DPcells only were present. CD68neg DPcells alone were detected in a single sample. Among the 20 MBC cases, 11 were classified as stage IVaggressive and 9 as stage IVindolent (i.e. with ≥ 5 CTCs and &amp;lt; 5 CTCs, respectively). CD68pos DPcells were present in 5/11 stage IVaggressive and in 5/9 stage IVindolent patients, suggesting that they are independent from CTC-based classification. As expected, CD68 was not detected on the majority of CTCs (796 out of 841), but, interestingly, 5% of CTCs were CD68pos. Conclusions and future perspectives: These preliminary results suggest that DPcells can derive from heterotypic cell fusion between tumor cells and macrophages. This would provide a new perspective on the unique interaction between tumor cells and the microenvironment and the potential role of these new cell entity in promoting disease progression. However, many questions about this subpopulation of circulating cells remain unanswered and future studies are needed to better characterize DPcells at both phenotypic and genomic level, to understand their biological and clinical relevance. Citation Format: Carolina Reduzzi, Paolo D'Amico, Youbin Zhang, Vera Cappelletti, Massimo Cristofanilli. Expression of CD68 on CKpos/CD45pos circulating cells in breast cancer patients: An additional hint supporting the fusion hybrid theory [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 586.