Spatial molecular profiling of mixed invasive ductal and lobular breast cancers reveals heterogeneity in intrinsic molecular subtypes, oncogenic signatures, and mutations.

Mixed invasive ductal and lobular carcinoma (MDLC) is a rare histologic subtype of breast cancer displaying both E-cadherin positive ductal and E-cadherin negative lobular morphologies within the same tumor, posing challenges with regard to anticipated clinical management. It remains unclear whether these distinct morphologies also have distinct biology and risk of recurrence. Our spatially resolved transcriptomic, genomic, and single-cell profiling revealed clinically significant differences between ductal and lobular tumor regions including distinct intrinsic subtype heterogeneity - e.g., MDLC with triple-negative breast cancer (TNBC) or basal ductal and estrogen receptor positive (ER+) luminal lobular regions, distinct enrichment of cell cycle arrest/senescence and oncogenic (ER and MYC) signatures, genetic and epigenetic CDH1 inactivation in lobular but not ductal regions, and single-cell ductal and lobular subpopulations with unique oncogenic signatures further highlighting intraregional heterogeneity. Altogether, we demonstrated that the intratumoral morphological/histological heterogeneity within MDLC is underpinned by intrinsic subtype and oncogenic heterogeneity which may result in prognostic uncertainty and therapeutic dilemma.

Peripheral blood immune parameters, response, and adverse events after neoadjuvant chemotherapy plus durvalumab in early-stage triple-negative breast cancer.

PURPOSE: We evaluated T- and B-cell receptor (TCR and BCR) repertoire diversity and 38 serum cytokines in pre- and post-treatment peripheral blood of 66 patients with triple-negative breast cancer (TNBC) who received neoadjuvant chemotherapy plus durvalumab and assessed associations with pathologic response and immune-related adverse events (irAEs) during treatment. METHODS: Genomic DNA was isolated from buffy coat for TCR and BCR clonotype profiling using the Immunoseq platform and diversity was quantified with Pielou's evenness index. MILLIPLEX MAP Human Cytokine/Chemokine Magnetic Bead Panel was used to measure serum cytokine levels, which were compared between groups using moderated t-statistic with Benjamini-Hochberg correction for multiple testing. RESULTS: TCR and BCR diversity was high (Pielou's index > 0.75) in all samples. Baseline receptor diversities and change in diversity pre- and post-treatment were not associated with pathologic response or irAE status, except for BCR diversity that was significantly lower post-treatment in patients who developed irAE (unadjusted p = 0.0321). Five cytokines increased after treatment in patients with pathologic complete response (pCR) but decreased in patients with RD, most prominently IL-8. IFNγ, IL-7, and GM-CSF levels were higher in pre-treatment than in post-treatment samples of patients who developed irAEs but were lower in those without irAEs. CONCLUSION: Baseline peripheral blood cytokine levels may predict irAEs in patients treated with immune checkpoint inhibitors and chemotherapy, and increased post-treatment B-cell clonal expansion might mediate irAEs.

Notch-RBP-J signaling regulates the transcription factor IRF8 to promote inflammatory macrophage polarization.

Emerging concepts suggest that the functional phenotype of macrophages is regulated by transcription factors that define alternative activation states. We found that RBP-J, the main nuclear transducer of signaling via Notch receptors, augmented Toll-like receptor 4 (TLR4)-induced expression of key mediators of classically activated M1 macrophages and thus of innate immune responses to Listeria monocytogenes. Notch-RBP-J signaling controlled expression of the transcription factor IRF8 that induced downstream M1 macrophage-associated genes. RBP-J promoted the synthesis of IRF8 protein by selectively augmenting kinase IRAK2-dependent signaling via TLR4 to the kinase MNK1 and downstream translation-initiation control through eIF4E. Our results define a signaling network in which signaling via Notch-RBP-J and TLRs is integrated at the level of synthesis of IRF8 protein and identify a mechanism by which heterologous signaling pathways can regulate the TLR-induced inflammatory polarization of macrophages.

CDK4/6 inhibitors: The Devil is in the Detail.

PURPOSE OF REVIEW: Update on the most recent clinical evidence on CDK4/6 inhibitors (CDK4/6i) in the treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor (HER)2-negative breast cancer. RECENT FINDINGS: Over the past decade, CDK4/6i have become part of the standard of care treatment of patients with both metastatic and high-risk early HR + /HER2- breast cancers. The three available CDK4/6i (palbociclib, ribociclib and abemaciclib) have been extensively studied in combination with endocrine therapy (ET) in metastatic breast cancer (mBC) with consistent prolongation of progression free survival; however, ribociclib has emerged as the preferred first line agent in mBC given overall survival benefit over endocrine monotherapy. In early BC, abemaciclib is the only currently approved agent while ribociclib has early positive clinical trial data. Toxicities and financial burden limit the use of CDK4/6i in all patients and resource-poor settings, and optimal timing of their use in mBC remains unclear. There is considerable evidence for the use of CDK4/6i in metastatic and early HR + /HER2- breast cancer, but knowledge gaps remain, and further research is necessary to better define their optimal use.

Persistence to extended adjuvant endocrine therapy following Breast Cancer Index (BCI) testing in women with early-stage hormone receptor-positive (HR +) breast cancer.

PURPOSE: Extending adjuvant endocrine therapy (ET) beyond the standard 5 years offers added protection against late breast cancer recurrences in women with early-stage hormone receptor-positive (HR +) breast cancer. Little is known about treatment persistence to extended ET (EET) and the role that genomic assays may play. In this study, we evaluated persistence to EET in women who had Breast Cancer Index (BCI) testing. METHODS: Women with stage I-III HR + breast cancer who had BCI testing after at least 3.5 years of adjuvant ET and ≥ 7 years of follow-up after diagnosis were included (n = 240). Data on medication persistence was based on prescriptions in the electronic health record. RESULTS: BCI predicted 146 (61%) patients to have low - BCI (H/I)-low - and 94 (39%) patients to have high likelihood of benefit from EET (BCI (H/I)-high). Continuation of ET after BCI occurred in 76 (81%) (H/I)-high and 39 (27%) (H/I)-low patients. Non-persistence rates were 19% in the (H/I)-high and 38% in the (H/I)-low group. The most common reason for non-persistence was intolerable side effects. Patients on EET underwent more DXA bone density scans than those who stopped ET at 5 years (mean 2.09 versus 1.27; p < 0.001). At a median follow-up of 10 years from diagnosis, there were 6 metastatic recurrences. CONCLUSIONS: In patients who continued ET after BCI testing, the rates of persistence to EET were high, particularly in patients with predicted high likelihood of benefit from EET. Use of EET is associated with increased use of DXA scans.

Disease Progression in Children With Perinatal Human Immunodeficiency Virus Correlates With Increased PD-1+ CD8 T Cells That Coexpress Multiple Immune Checkpoints.

BACKGROUND: PD-1 marks exhausted T cells, with weak effector functions. Adults living with human immunodeficiency virus (HIV) have increased levels of PD-1+ CD8 T cells that correlate with HIV disease progression, yet little is known about the role of PD-1+ CD8 T cells in children with perinatal HIV. METHODS: We enrolled 76 Kenyan children with perinatal HIV and 43 children who were HIV unexposed and quantified PD-1 levels on CD8 T cells; their coexpression with immune checkpoints (ICs) 2B4, CD160, and TIM3; correlates with immune activation and HIV disease progression; and HIV-specific and -nonspecific proliferative responses. RESULTS: PD-1+ CD8 T-cell frequencies are elevated in children with perinatal HIV and associated with disease progression. The majority of PD-1+ CD8 T cells coexpress additional ICs. ART initiation lowers total PD-1 levels and coexpression of multiple ICs. The frequency of PD-1+2B4+CD160+TIM3- in PD-1+ CD8 T cells predicts weaker HIV-specific proliferative responses, suggesting that this subset is functionally exhausted. CONCLUSIONS: Children with perinatal HIV have high levels of PD-1+ CD8 T cells that are a heterogeneous population differentially coexpressing multiple ICs. Understanding the complex interplay of ICs is essential to guide the development of PD-1-directed immunotherapies for pediatric HIV remission and cure.

Optimal Management for Residual Disease Following Neoadjuvant Systemic Therapy.

OPINION STATEMENT: Treatment sequencing in early-stage breast cancer has significantly evolved in recent years, particularly in the triple negative (TNBC) and human epidermal growth factor receptor 2 (HER2)-positive subsets. Instead of surgery first followed by chemotherapy, several clinical trials showed benefits to administering systemic chemotherapy (and HER2-targeted therapies) prior to surgery. These benefits include more accurate prognostic estimates based on the extent of residual cancer that can also guide adjuvant treatment, and frequent tumor downstaging that can lead to smaller surgeries in patients with large tumors at diagnosis. Patients with extensive invasive residual cancer after neoadjuvant therapy are at high risk for disease recurrence, and two pivotal clinical trials, CREATE-X and KATHERINE, demonstrated improved recurrence free survival with adjuvant capecitabine and ado-trastuzumab-emtansine (T-DM1) in TNBC and HER2-positive residual cancers, respectively. Patients who achieve pathologic complete response (pCR) have excellent long-term disease-free survival regardless of what chemotherapy regimen induced this favorable response. This allows escalation or de-escalation of adjuvant therapy: patients who achieved pCR could be spared further chemotherapy, while those with residual cancer could receive additional chemotherapy postoperatively. Ongoing clinical trials are testing this strategy (CompassHER2-pCR: NCT04266249). pCR also provides an opportunity to assess de-escalation of locoregional therapies. Currently, for patients with residual disease in the lymph nodes (ypN+), radiation therapy entails coverage of the undissected axilla, and may include supra/infraclavicular/internal mammary nodes in addition to the whole breast or chest wall, depending on the type of surgery. Ongoing trials are testing the safety of omitting post-mastectomy breast and post-lumpectomy nodal irradiation (NCT01872975) as well as omitting axillary lymph node dissection (NCT01901094) in the setting of pCR. Additionally, evolving technologies such as minimal residual disease (MRD) monitoring in the blood during follow-up may allow early intervention with "second-line systemic adjuvant therapy" for patients with molecular relapse which might prevent impending clinical relapse.

Changing frameworks in treatment sequencing of triple-negative and HER2-positive, early-stage breast cancers.

Important results are emerging from clinical trials showing that surgery followed by chemotherapy might not be the optimal strategy to maximise a patient's chance of survival from triple-negative or HER2-positive breast cancers. Administering chemotherapy before surgery provides an opportunity to directly observe the efficacy of a particular chemotherapy regimen. Patients who have extensive residual invasive cancer after neoadjuvant chemotherapy are at a high risk of recurrence for metastatic disease, which, in turn, make these patients ideal candidates for clinical trials. Two important clinical trials, CREATE-X (UMIN000000843) and KATHERINE (NCT01772472), have shown improved disease-free survival with postoperative capecitabine and ado-trastuzumab emtansine in patients with either triple-negative or HER2-positive breast cancer who had residual disease after neoadjuvant chemotherapy. The opportunity for residual-disease guided therapy, as observed in these trials, is lost when patients undergo surgery first. In this Personal View, we discuss the clinical implications of the CREATE-X and KATHERINE trials and place them into context with other developments in the adjuvant setting of early-stage breast cancer. We suggest that neoadjuvant systemic therapy should be considered as the new standard of care for HER2-positive and oestrogen receptor negative breast cancer, even for patients who present with operable (T1 or T2) disease.

Single-arm, neoadjuvant, phase II trial of pertuzumab and trastuzumab administered concomitantly with weekly paclitaxel followed by 5-fluoruracil, epirubicin, and cyclophosphamide (FEC) for stage I-III HER2-positive breast cancer.

PURPOSE: The purpose of this two-cohort Phase II trial was to estimate the pathologic complete response (pCR: ypT0/is ypN0) rate when trastuzumab plus pertuzumab are administered concurrently during both the taxane and anthracycline phases of paclitaxel and 5-fluorouracil/epirubicin/cyclophosphamide (FEC) neoadjuvant chemotherapy. METHODS: The pCR rates were assessed separately in hormone receptor (HR) positive and negative cases following Simon's two-stage design, aiming to detect a 20% absolute improvement in pCR rates from 50 to 70 and 70 to 90% in the HR-positive and HR-`negative cohorts, respectively. RESULTS: The HR-negative cohort completed full accrual of 26 patients; pCR rate was 80% (95% CI 60-91%). The HR+ cohort was closed early after 24 patients due to lower than expected pCR rate of 26% (95% CI 13-46%) at interim analysis. Overall, 44% of patients (n = 22/50) experienced grade 3/4 adverse events. The most common were neutropenia (n = 10) and diarrhea (n = 7). There was no symptomatic heart failure, but 28% (n = 14) had ≥ 10% asymptomatic decrease in LVEF; in one patient, LVEF decreased to < 50%. Cardiac functions returned to baseline by the next assessment in 57% (8/14) of cases. CONCLUSIONS: Eighty percent of HR-negative, HER2-positive breast cancers achieve pCR with paclitaxel/FEC neoadjuvant chemotherapy administered concomitantly with pertuzumab and trastuzumab. These results are similar to pCR rates seen in trials using HER2-targeted therapy during the taxane phase only of sequential taxane-anthracycline regimens and suggest that we have reached a therapeutic plateau with HER2-targeted therapies combined with chemotherapy in the neoadjuvant setting.

Cytomegalovirus resistance in CD34+ -selected hematopoietic cell transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) viremia after CD34+ -selected hematopoietic stem cell transplant (HCT) often requires prolonged antiviral therapy. We report rates and outcomes of resistant CMV in a contemporary cohort of CD34+ -selected HCT recipients managed preemptively. METHODS: We retrospectively reviewed 220 consecutive, CMV-seropositive recipients (R+), who received CD34+ -selected HCT at Memorial Sloan Kettering Cancer Center between June 2010 and December 2014. Patients were monitored by quantitative CMV PCR and were treated preemptively. CMV resistance was tested by a genotypic assay. RESULTS: One hundred and sixty-one (73%) patients developed CMV viremia and 47 (29% of viremic and 21% of total patients) had CMV resistance testing by one-year from HCT. CMV resistance was confirmed in 19 (12% of viremic and 9% of total) patients and was identified >3 months from HCT in 90% of patients. Twelve patients had mutations in UL97 only; the remaining 7 patients had mutations in UL54 only or UL54 and UL97. By 1 year from HCT, 11 of 19 (58%) patients with mutations had CMV end-organ disease. CMV-related mortality in patients with resistance was 42%. CONCLUSIONS: Nine percent of CMV R+, CD34+ -selected HCT recipients had resistant CMV by 1 year from HCT. Of 19 patients with resistant CMV, 58% had CMV end-organ disease and 42% died of CMV. Effective strategies for CMV prevention and restoration of CMV immunity are needed for CD34+ -selected HCT.

HIV-Infected Children Have Elevated Levels of PD-1+ Memory CD4 T Cells With Low Proliferative Capacity and High Inflammatory Cytokine Effector Functions.

Background: During human immunodeficiency virus (HIV) disease, chronic immune activation leads to T-cell exhaustion. PD-1 identifies "exhausted" CD8 T cells with impaired HIV-specific effector functions, but its role on CD4 T cells and in HIV-infected children is poorly understood. Methods: In a Kenyan cohort of vertically HIV-infected children, we measured PD-1+ CD4 T-cell frequencies and phenotype by flow cytometry and their correlation with HIV disease progression and immune activation. Second, in vitro CD4 T-cell proliferative and cytokine responses to HIV-specific and -nonspecific stimuli were assessed with and without PD-1 blockade. Results: HIV-infected children have increased frequencies of PD-1+ memory CD4 T cells that fail to normalize with antiretroviral treatment. These cells are comprised of central and effector memory subsets and correlate with HIV disease progression, measured by viral load, CD4 percentage, CD4:CD8 T-cell ratio, and immune activation. Last, PD-1+ CD4 T cells predict impaired proliferative potential yet preferentially secrete the Th1 and Th17 cytokines interferon-γ and interleukin 17A, and are unresponsive to in vitro PD-1 blockade. Conclusions: This study highlights differences in PD-1+ CD4 T-cell memory phenotype and response to blockade between HIV-infected children and adults, with implications for potential immune checkpoint therapies.

Integrated regulation of Toll-like receptor responses by Notch and interferon-gamma pathways.

Toll-like receptor (TLR) responses are regulated to avoid toxicity and achieve coordinated responses appropriate for the cell environment. We found that Notch and TLR pathways cooperated to activate canonical Notch target genes, including transcriptional repressors Hes1 and Hey1, and to increase production of canonical TLR-induced cytokines TNF, IL-6, and IL-12. Cooperation by these pathways to increase target gene expression was mediated by the Notch-pathway component and transcription factor RBP-J, which also contributed to lethality after endotoxin injection. TLR- and Notch-induced Hes1 and Hey1 attenuated IL-6 and IL-12 production. This Hes1- and Hey1-mediated feedback inhibitory loop was abrogated by interferon-gamma (IFN-gamma), which blocked TLR-induced activation of canonical Notch target genes by inhibiting Notch2 signaling and downstream transcription. These findings identify new immune functions for RBP-J, Hes, and Hey proteins and provide insights into mechanisms by which Notch, TLR, and IFN-gamma signals are integrated to modulate specific effector functions in macrophages.

Cytomegalovirus Infection after CD34(+)-Selected Hematopoietic Cell Transplantation.

The effectiveness of preemptive treatment (PET) for cytomegalovirus (CMV) in recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) by CD34(+) selection is not well defined. We analyzed 213 adults who received TCD-HCT at our institution from June 2010 through May 2014. Patients were monitored by a CMV quantitative PCR assay if recipient (R) or donor (D) were CMV seropositive. CMV viremia occurred early (median, 27 days after HCT) in 91 of 213 (42.7%) patients for a 180-day cumulative incidence of 84.5%, 61.8%, and 0 for R+/D+, R+/D-, and R-/D+ patients, respectively. CMV disease occurred in 5% of patients. In Cox regression analysis, R+/D+ status was associated with increased risk for CMV viremia compared with R+/D- (hazard ratio [HR], 1.79, 95% confidence interval [CI], 1.16 to 2.76, P = .01), whereas matched unrelated donor allograft was associated with decreased risk (HR, .62; 95% CI, .39 to .97, P = .04). Of 91 patients with CMV viremia, 52 (57%) had persistent viremia (>28 days duration). Time lag from detection of CMV viremia to PET was associated with incremental risk for persistent viremia (HR, 1.09; 95% CI, 1.01 to 1.18; P = .03). Overall, 166 of 213 (77.9%) patients were alive 1 year after HCT, with no difference between patients with and without CMV viremia or among the different CMV serostatus pairs (P = not significant). CMV viremia occurred in 70% of R + TCD-HCT. Delay in PET initiation was associated with persistent viremia. With PET, CMV R/D serostatus did not adversely impact survival in TCD-HCT on 1-year survival in the present cohort.

Long-term outcomes by lobular versus ductal histology in four NSABP adjuvant breast cancer trials.

We evaluated differences in long-term outcomes of invasive lobular carcinoma (ILC) vs breast cancers of no special type (NST) treated with anthracycline-based adjuvant chemotherapy using 4 National Surgical Adjuvant Breast and Bowel Project (NSABP) randomized phase III trials (B-22, B-25, B-28, B-30). Our cohort included 11,251 patients with NST and 1,231 with ILC. Patients with ILC were older, had larger and more often estrogen receptor-positive tumors, and more positive lymph nodes. During early follow-up (0-5 years), patients with ILC had fewer recurrences (HR: 0.797; 95% confidence interval [CI] 0.685-0.929) and deaths (HR: 0.756; 95% CI 0.623-0.917). After 5 years patients with ILC had more recurrences (HR: 1.30; 95% CI 1.085-1.558) and deaths (HR: 1.044; 95% CI 0.898-1.214). Conditional probability analysis showed significant interactions between time-period and histologic type for recurrences (p < .001) and deaths (p < .001). Patients with ILC have elevated risk of late recurrence and death compared to patients with NST.

Immune Infiltration Correlates with Transcriptomic Subtypes in Primary ER+ Invasive Lobular Breast Cancer.

Understanding interplay of breast cancer and microenvironment is critical. Here, we identified two transcriptomic subtypes and five immune infiltration patterns from RNA-seq and multiplex immunohistochemistry from 21 ER+/HER2- invasive lobular breast cancers. The proliferative subtype associated with increased immune infiltration especially by immunosuppressive regulatory T-cells and macrophages. We also defined a TAM-Low signature, which associated with lower infiltration of proliferative, pro-inflammatory TAM, and improved outcome in patients with ER+ tumors.

Spatial molecular profiling of mixed invasive ductal-lobular breast cancers reveals heterogeneity in intrinsic molecular subtypes, oncogenic signatures, and mutations.

Mixed invasive ductal and lobular carcinoma (MDLC) is a rare histologic subtype of breast cancer displaying both E-cadherin positive ductal and E-cadherin negative lobular morphologies within the same tumor, posing challenges with regard to anticipated clinical management. It remains unclear whether these distinct morphologies also have distinct biology and risk of recurrence. Our spatially-resolved transcriptomic, genomic, and single-cell profiling revealed clinically significant differences between ductal and lobular tumor regions including distinct intrinsic subtype heterogeneity (e.g., MDLC with TNBC/basal ductal and ER+/luminal lobular regions), distinct enrichment of senescence/dormancy and oncogenic (ER and MYC) signatures, genetic and epigenetic CDH1 inactivation in lobular, but not ductal regions, and single-cell ductal and lobular sub-populations with unique oncogenic signatures further highlighting intra-regional heterogeneity. Altogether, we demonstrated that the intra-tumoral morphological/histological heterogeneity within MDLC is underpinned by intrinsic subtype and oncogenic heterogeneity which may result in prognostic uncertainty and therapeutic dilemma. Significance: MDLC displays both ductal and lobular tumor regions. Our multi-omic profiling approach revealed that these morphologically distinct tumor regions harbor distinct intrinsic subtypes and oncogenic features that may cause prognostic uncertainty and therapeutic dilemma. Thus histopathological/molecular profiling of individual tumor regions may guide clinical decision making and benefit patients with MDLC, particularly in the advanced setting where there is increased reliance on next generation sequencing.

Exercise and nutrition to improve cancer Treatment-Related outcomes (ENICTO).

Chemotherapy treatment-related side-effects are common and increase the risk of suboptimal outcomes. Exercise interventions during cancer treatment improve self-reported physical functioning, fatigue, anxiety, and depression, but it is unclear whether these interventions improve important clinical outcomes, such as chemotherapy relative dose intensity (RDI). The National Cancer Institute funded the Exercise and Nutrition to Improve Cancer Treatment-Related Outcomes (ENICTO) Consortium, to address this knowledge gap. This paper describes the mechanisms hypothesized to underpin intervention effects on clinically-relevant treatment outcomes, briefly outlines each project's distinct research aims, summarizes the scope and organizational structure of ENICTO, and provides an overview of the integrated common data elements used to pursue research questions collectively. In addition, the paper includes a description of consortium-wide activities and broader research community opportunities for collaborative research. Findings from the ENICTO Consortium have the potential to accelerate a paradigm shift in oncology care such that cancer patients could receive exercise and nutrition programming as the standard of care in tandem with chemotherapy to improve RDI for a curative outcome.

Case report: abemaciclib-induced syndrome of inappropriate antidiuretic hormone (SIADH) without underlying kidney injury in a patient with early-stage estrogen receptor (ER)+ breast cancer.

The CDK4/6 inhibitor, abemaciclib, is now the standard of care adjuvant therapy for patients with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) tumors at high risk of recurrence. Real-world usage uncovers emerging side effects that may have been previously unreported in clinical trials. Here, we present the clinical course of a patient who developed a syndrome of inappropriate antidiuretic hormone (SIADH) without underlying kidney injury due to abemaciclib use.

Pharmacology and pharmacokinetics of elacestrant.

Elacestrant, a novel oral selective estrogen receptor (ER) degrader (SERD), was approved by the Food and Drug Administration (FDA) on January 27, 2023, for use in patients with ER and/or progesterone receptor (PR)-positive and HER2-negative metastatic breast cancer whose tumors harbor an ESR1 missense mutation (ESR1-mut), after at least one line of endocrine therapy (ET). The FDA made its decision based on the randomized phase 3 EMERALD trial, which met its primary endpoint of improved median progression-free survival (mPFS) with elacestrant monotherapy versus standard-of-care endocrine monotherapy in the overall intention to treat population; however, this benefit was largely driven by the ESR1-mut cohort. Elacestrant is a dose-dependent mixed ER agonist/antagonist, which at high doses acts as a direct ER antagonist as well as selective downregulator of ER. It is 11% bioavailable, primarily metabolized by CYP3A4 in the liver and excreted in feces. This leads to drug-drug interactions with strong CYP3A4 inhibitors and inducers, such as itraconazole and rifampin, respectively. In accordance with its clearance route, dose reduction is recommended in patients with moderate hepatic dysfunction but not in renal dysfunction. Studies evaluating elacestrant in severe hepatic dysfunction as well as in patients from racial and ethnic minority groups are ongoing. Overall, elacestrant is the first orally bioavailable SERD approved by the FDA for use in patients with metastatic breast cancer. Current clinical trials are ongoing evaluating it in the adjuvant setting in patients with early stage ER-positive breast cancers.

Oncotype DX results increase concordance in adjuvant chemotherapy recommendations for early-stage breast cancer.

Adjuvant chemotherapy recommendations for ER+/HER2- early-stage breast cancers (eBC) involve integrating prognostic and predictive information which rely on physician judgment; this can lead to discordant recommendations. In this study we aim to evaluate whether Oncotype DX improves confidence and agreement among oncologists in adjuvant chemotherapy recommendations. We randomly select 30 patients with ER+/HER2- eBC and recurrence score (RS) available from an institutional database. We ask 16 breast oncologists with varying years of clinical practice in Italy and the US to provide recommendation for the addition of chemotherapy to endocrine therapy and their degree of confidence in the recommendation twice; first, based on clinicopathologic features only (pre-RS), and then with RS result (post-RS). Pre-RS, the average rate of chemotherapy recommendation is 50.8% and is higher among junior (62% vs 44%; p < 0.001), but similar by country. Oncologists are uncertain in 39% of cases and recommendations are discordant in 27% of cases (interobserver agreement K 0.47). Post-RS, 30% of physicians change recommendation, uncertainty in recommendation decreases to 5.6%, and discordance decreases to 7% (interobserver agreement K 0.85). Interpretation of clinicopathologic features alone to recommend adjuvant chemotherapy results in 1 out of 4 discordant recommendations and relatively high physician uncertainty. Oncotype DX results decrease discordancy to 1 out of 15, and reduce physician uncertainty. Genomic assay results reduce subjectivity in adjuvant chemotherapy recommendations for ER +/HER2- eBC.