Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: updated efficacy and Ki-67 analysis from the monarchE study

A Digital Home-Based Health Care Center for Remote Monitoring of Side Effects During Breast Cancer Therapy: Prospective, Single-Arm, Monocentric Feasibility Study

Background

The introduction of oral anticancer therapies has, at least partially, shifted treatment from clinician-supervised hospital care to patient-managed home regimens. However, patients with breast cancer receiving oral cyclin-dependent kinase 4/6 inhibitor therapy still require regular hospital visits to monitor side effects. Telemonitoring has the potential to reduce hospital visits while maintaining quality care.

Objective

This study aims to develop a digital home-based health care center (DHHC) for acquiring electrocardiograms (ECGs), white blood cell (WBC) counts, side effect photo documentation, and patient-reported quality of life (QoL) data.

Methods

The DHHC was set up using an Apple Watch Series 6 (ECG measurements), a HemoCue WBC DIFF Analyzer (WBC counts), an iPhone SE (QoL assessments and photo documentation), a TP-Link M7350-4G Wi-Fi router, and a Raspberry Pi 4 Model B. A custom-built app stored and synchronized remotely collected data with the clinic. The feasibility and acceptance of the DHHC among patients with breast cancer undergoing cyclin-dependent kinase 4/6 inhibitor therapy were evaluated in a prospective, single-arm, monocentric study. Patients (n=76) monitored side effects-ECGs, WBC counts, photo documentation, and QoL-at 3 predefined time points: study inclusion (on-site), day 14 (remote), and day 28 (remote). After the study completion, patients completed a comprehensive questionnaire on user perception and feasibility. Adherence to scheduled visits, the success rate of the data transfer, user perception and feasibility, and the clinical relevance of remote measurements were evaluated.

Results

Mean adherence to the planned remote visits was 63% on day 14 and 37% on day 28. ECG measurements were performed most frequently (day 14: 57/76, 75%; day 28: 31/76, 41%). The primary patient-reported reason for nonadherence was device malfunction. The expected versus the received data transfer per patient was as follows: ECGs: 3 versus 3.04 (SD 1.9); WBC counts: 3 versus 2.14 (SD 1.14); QoL questionnaires: 3 versus 2.5 (SD 1.14); and photo documentation: 6 versus 4.4 (SD 3.36). Among patients, 81% (55/68) found ECG measurements easy, 82% (55/67) found photo documentation easy, and 48% (33/69) found WBC measurements easy. Additionally, 61% (40/66) of patients felt comfortable with self-monitoring and 79% (54/68) were willing to integrate remote monitoring into their future cancer care. Therapy-induced decreased neutrophil count was successfully detected (P<.001; mean baseline: 4.3, SD 2.2, ×109/L; on-treatment: 1.8, SD 0.8, ×109/L). All-grade neutropenia and corrected QT interval prolongations were detected in 80% (55/68) and 2% (1/42) of patients, respectively.

Conclusions

Adherence to scheduled remote visits was moderate, with nonadherence primarily attributed to device-related complications, which may have also affected the success rate of data transfer. Overall, patients considered remote monitoring useful and feasible. The prevalence of reported adverse events was comparable to existing literature, suggesting clinical potential. This initial feasibility study highlights the potential of the DHHC.

Health-Related Quality of Life in Patients with HR+/HER2- Early Breast Cancer Treated with Ribociclib Plus a Nonsteroidal Aromatase Inhibitor: Results from the NATALEE Trial

PURPOSE

The phase III NATALEE trial reported a statistically significant invasive disease-free survival benefit with ribociclib plus nonsteroidal aromatase inhibitor (NSAI) versus an NSAI alone in stage II/III hormone receptor-positive, HER2-negative (HR+/HER2-) early breast cancer. In this study, we report health-related quality of life (HRQOL) data from NATALEE.

PATIENTS AND METHODS

Patients were randomized to receive ribociclib plus NSAI or NSAI alone. Patient-reported outcome scores [European Organisation for Research and Treatment of Cancer core quality of life questionnaire global health status and physical, social, and emotional functioning domains; the supplementary European Organisation for Research and Treatment of Cancer breast cancer-specific QOL questionnaire breast symptoms scale; health on a visual analog scale of the generic EuroQOL 5-level instrument; and the Hospital Anxiety and Depression Scale] were assessed. The prespecified primary HRQOL endpoint was physical functioning. Mean scores and time-categorical and prespecified linear-time repeated-measure models were used to evaluate HRQOL changes during treatment.

RESULTS

HRQOL was evaluated in all patients in the ribociclib plus NSAI (n = 2,549) and NSAI alone (n = 2,552) arms. Compliance was high in both arms (≈93%-97%). Mean scores did not differ meaningfully from baseline for any analyzed domain. Likewise, neither a meaningful change from baseline (in either treatment arm) nor a difference between arms was observed during treatment in the time-categorical, model-adjusted mean scores for any HRQOL domains-using published thresholds for interpreting longitudinal and between-group differences, with all values being within 0.5 SD of their baseline values. Linear-time regression analysis confirmed these findings.

CONCLUSIONS

These analyses of NATALEE show that adding adjuvant ribociclib to an NSAI does not negatively affect HRQOL in patients with HR+/HER2- early breast cancer.

Risk factors for early recurrence in patients with hormone receptor-positive, HER2-negative breast cancer: a retrospective cohort study in Japan (WJOG15721B)

BACKGROUND

Patients with early recurrence of hormone receptor (HR)-positive, HER2-negative (HR+/HER2-) breast cancer have a poor prognosis. We aimed to identify clinical and pathological risk factors for recurrence within three years after surgery of HR+/HER2- breast cancer.

METHODS

We retrospectively reviewed clinical data of patients with stage II-III HR+/HER2- breast cancer who received adjuvant endocrine therapy from January 1, 2012 to January 1, 2017 at five institutions. Using univariable and multivariable analyses, we determined risk factors for invasive disease-free survival (IDFS). A nomogram was generated using variables from the multivariable analysis to predict 3-year IDFS rate.

RESULTS

A total of 2732 patients were analyzed, with a median follow-up of 7.1 years. The 3-year IDFS rate was 92.1%. Multivariable analysis for IDFS revealed significant risk factors: age (40-69 vs. 20-39 years: HR 0.69, p = 0.011), nuclear grade (Grade 2 vs. Grade 1: HR 1.66, p < 0.001; Grade 3 vs. Grade 1: HR 1.64, p < 0.001), vascular invasion (Yes vs. No: HR 1.36, p = 0.027), pathological invasive tumor size (2-5 cm vs. < 2 cm: HR 1.75, p < 0.001; ≥ 5 cm vs. < 2 cm: HR 2.07, p < 0.001), number of positive lymph nodes (≥ 4 vs.0: HR 1.70, p < 0.001), and neoadjuvant chemotherapy (NAC) (Yes vs. No: HR 2.41, p < 0.001). The nomogram's concordance index was 0.68.

CONCLUSION

Younger age, nuclear grade, vascular invasion, tumor size and number of lymph node metastases were identified as independent risk factors for early recurrence. Patients whose physicians chose NAC had worse survival than those who did not.

Post-progression treatment options after CDK4/6 inhibitors in hormone receptor-positive, HER2-negative metastatic breast cancer

The combination of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) and endocrine therapy (ET) is the standard first-line treatment for hormone receptor-positive (HR + ) and HER2-negative metastatic breast cancer (mBC). Despite their efficacy, resistance inevitably develops, necessitating alternative therapeutic strategies post-progression. This review explores current and emerging treatment options following progression on CDK4/6i, focusing on endocrine therapies, targeted therapies, combination approaches, and the continued use of CDK4/6i. Endocrine therapies, including fulvestrant and novel oral selective estrogen receptor degraders (SERDs) like elacestrant, show promise, especially in patients with ESR1 mutations. Targeted therapies such as PI3K/AKT/mTOR inhibitors, exemplified by alpelisib and capivasertib, offer potential by addressing downstream signaling pathways involved in resistance. Additionally, FGFR inhibitors like erdafitinib are under investigation for their role in overcoming specific resistance mechanisms. Combination strategies involving CDK4/6 inhibitors with immune checkpoint inhibitors or other targeted agents are also being explored, with early trials suggesting possible synergistic effects, although further validation is required. Continuation of CDK4/6 inhibitors beyond progression has shown potential benefits in selected patients, but the data are heterogeneous, and further studies are needed to clarify their role. While chemotherapy remains a standard option for patients who progress on these treatments, the goal is to delay its use through the effective utilization of endocrine and targeted therapies. Understanding resistance mechanisms and tailoring treatment to individual patient profiles is crucial for optimizing outcomes. Ongoing clinical trials are expected to provide deeper insights, guiding the development of more effective post-progression therapeutic strategies. This evolving landscape highlights the need for continuous research and individualized patient care to improve survival and quality of life in HR + mBC patients.

New Therapeutic Scenarios in the Context of Adjuvant Treatment for HR+/HER2-Breast Cancer: The Possible Role of Ribociclib in Treatment Algorithms for Stage II and III

Early breast cancer (EBC) treatment has evolved from radical surgery to a multidisciplinary approach, integrating radiotherapy, chemotherapy, targeted therapy, and hormone therapy with surgery to ensure the best possible outcome. Despite these advancements, hormone receptor-positive (HR+)/Human Epidermal Growth Factor Receptor 2-Negative (HER2-) EBC still faces high recurrence rates after endocrine therapy. A panel of oncologists from Central-Southern Italy discussed the profile of ribociclib as an adjuvant therapy, based on the results of the NATALEE study, focusing on efficacy, safety, patient profiles, and regional challenges in treatment access. The experts identified ribociclib as suitable adjuvant treatment for stage II and III HR+/HER2- EBC patients, including those without lymph node involvement but with biologically aggressive disease. In their view, ribociclib could be an interesting option for patients not eligible for chemotherapy due to contraindications. Key challenges in translating the evidence on ribociclib in EBC into clinical practice include treatment duration, patient follow-up, and adverse events management. Strategies to address these challenges range from telemedicine and support from local clinics to tailored communication to improve adherence. Ribociclib is expected to significantly impact adjuvant treatment for HR+/HER2- EBC by addressing broader patient needs and potentially improving long-term outcomes through enhanced adherence and personalized management strategies.

Clinician's guide: expert insights on the use of CDK4/6 inhibitors in patients with early breast cancer

The introduction of the cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors abemaciclib and ribociclib to the adjuvant setting marks a significant advancement in the treatment of hormone-receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer (HR+, HER2- EBC). Despite significant strides in early detection and treatment, many patients continue to face the risk of disease recurrence, highlighting the need for more effective adjuvant therapies. These CDK4/6 inhibitors, combined with adjuvant endocrine therapy, have shown promising efficacy in reducing recurrence rates while maintaining a manageable safety profile, as evidenced by the monarchE and NATALEE trials. This paper explores the integration of adjuvant CDK4/6 inhibitors into clinical practice, focusing on disease-free survival and safety outcomes. Key considerations in selecting between abemaciclib and ribociclib are discussed, including patient risk profiles, efficacy and safety profiles, treatment duration, and individual patient preferences. In addition, we discuss managing adverse events to prevent premature discontinuation, with strategies that include dose holds, dose reductions, proactive symptom management, and patient education. The paper also highlights strategies to enhance patient medication adherence and the involvement of multidisciplinary care teams to support treatment delivery. As research continues to evolve, additional follow-ups of the monarchE and NATALEE trials and future trials will further refine patient selection and treatment sequencing, ultimately improving outcomes and enhancing the quality of life for patients with HR+, HER2- EBC.

Models of Early Resistance to CDK4/6 Inhibitors Unveil Potential Therapeutic Treatment Sequencing

BACKGROUND

CDK4/6 inhibitors (CDK4/6i) combined with hormone therapies have demonstrated clinical benefit in HR+, HER2- breast cancer patients. However, the onset of resistance remains a concern and highlights a need for therapeutic strategies to improve outcomes. The objective of this study was to develop an in vitro model to better understand the mechanisms of resistance to CDK4/6i + hormone therapies and identify therapeutic strategies with potential to overcome this resistance.

METHODS

The HR+, HER2- T47D breast cancer cell line genetically modified with a Geminin-Venus reporter construct was treated with CDK4/6i (abemaciclib or palbociclib) in combination with 4-hydroxytamoxifen (tamoxifen). Resistant cells were identified by cell sorting for Geminin (%GEM+), a marker of the S/G2/M phases of the cell cycle, and confirmed by treatment with tamoxifen plus the CDK4/6i used to drive resistance. In resistant cells, following treatment with CDK4/6i + ET (tamoxifen or fulvestrant), the effects on cell proliferation (%GEM+) and viability, gene expression, and protein analysis to evaluate CDK4/6-cyclin D complex composition were examined.

RESULTS

Palbociclib + tamoxifen-resistant (PTxR) cells treated with abemaciclib + ET showed decreased %GEM+, %Ki67, and colony formation ability, compared to abemaciclib + tamoxifen-resistant (ATxR) cells treated with palbociclib + ET. Additionally, PTxR cells showed increased CDK4-p21 interaction, compared to ATxR. The CDK6 levels were greater in ATxR cells compared to PTxR cells, associated with CDK4/6i resistance. Additionally, abemaciclib + fulvestrant continued to robustly decrease pRb levels in PTxR models compared to palbociclib + fulvestrant in ATxR models. Transcriptome analysis revealed a depression of the cell cycle and E2F- and Rb-related genes in PTxR cells following treatment with abemaciclib + ET, not present in ATxR cells treated with palbociclib + ET. Both resistant models showed increased EGFR-related gene expression.

CONCLUSION

Taken together, we describe CDK4/6i-dependent mechanisms resulting in early-onset resistance to CDK4/6i + ET, using clinically relevant drug concentrations, in preclinical breast cancer cell models. The characterization of these preclinical models post progression on CDK4/6 inhibitor + ET treatment highlights the potential that the specific sequencing of CDK4/6 inhibitors could offer to overcome acquired resistance to CDK4/6i + ET. Abemaciclib + fulvestrant is currently under clinical investigation in patients with HR+, HER2- breast cancer and progression on prior CDK4/6i + ET (NCT05169567, postMONARCH).

Phase I study of ribociclib (CDK4/6 inhibitor) with spartalizumab (PD-1 inhibitor) with and without fulvestrant in metastatic hormone receptor-positive breast cancer or advanced ovarian cancer

BACKGROUND

Preclinical evidence suggests that cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors enhance antitumor immunity. We conducted a phase I trial of ribociclib (CDK4/6 inhibitor) plus spartalizumab (PD-1 inhibitor) in patients with hormone receptor (HR)-positive/HER2-negative metastatic breast cancer (MBC) or advanced ovarian cancer (AOC). The combination was also evaluated with fulvestrant in MBC.

METHODS

In Cohort A, ribociclib was administered on Days 1-21 (28-day cycle) starting at 400 mg, and spartalizumab at 400 mg on Day 1. Dose escalation was followed by expansion in AOC. Fulvestrant was added (Cohort B) with a safety run-in followed by expansion in MBC. Primary objectives were to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), and safety and tolerability of the combinations.

RESULTS

33 patients enrolled (n=18, Cohort A; n=15, Cohort B). The RP2D of ribociclib in both cohorts was 600 mg. Treatment-related adverse events in >20% of patients in either cohort were neutropenia, fatigue, anemia, thrombocytopenia, hypertransaminasemia, maculopapular rash, fatigue, and nausea. Hypertransaminasemia occurred in 66.7% (AST) and 46.7% (ALT) of patients in Cohort B, including 46.7% and 40.0%, respectively, of grade 3 or 4 events. Two confirmed partial responses were observed (13.3%) in Cohort B, in patients with low baseline serum thymidine kinase activity, coupled with an increase on-treatment. Peripheral blood flow cytometry across patients demonstrated on-target drug binding with increases in PD-1 occupancy and activated CD8+ T cells during treatment, irrespective of response. PD-L1-positivity, tumor-infiltrating lymphocytes, or tumor mutational burden did not correlate with progression-free survival (PFS). Several copy-number variations detected with next-generation sequencing correlated with PFS.

CONCLUSIONS

Ribociclib with spartalizumab and fulvestrant showed limited efficacy and elevated hepatotoxicity, precluding further development. Correlative analyses revealed treatment-induced immunological effects, and genomic alterations associated with PFS.

Imlunestrant Is an Oral, Brain-Penetrant Selective Estrogen Receptor Degrader with Potent Antitumor Activity in ESR1 Wild-Type and Mutant Breast Cancer

Targeting of the estrogen receptor (ER) by antiestrogens is the standard of care for patients with ER+ HER2- advanced/metastatic breast cancer. Although antiestrogens that degrade ERα (fulvestrant) or block estrogen production (aromatase inhibitors) have improved patient outcomes, clinically important challenges remain related to drug administration, limited bioavailability, lack of brain exposure, and acquired resistance due to ESR1 mutations. These limitations indicate a need for more robust ER-targeted therapies. Here, we discovered and characterized imlunestrant, a next-generation potent, brain-penetrant oral selective ER degrader. Imlunestrant degraded ERα and decreased ERα-mediated gene expression both in vitro and in vivo. Cell proliferation and tumor growth in ESR1 wild-type (WT) and mutant models were significantly inhibited by imlunestrant. Combining imlunestrant with abemaciclib (CDK4/6 inhibitor), alpelisib (PI3K inhibitor), or everolimus (mTOR inhibitor) further enhanced tumor growth inhibition, regardless of ESR1 mutational status. In an ER+ breast cancer intracranial tumor model, imlunestrant prolonged survival compared with vehicle or alternative selective ER degrader therapies. Together, these findings support the potential of imlunestrant to degrade ERα and suppress the growth of ESR1-WT and mutant breast cancer, including brain metastatic tumors. Significance: Imlunestrant, a next-generation, brain-penetrant oral ERα degrader, displays potent activity in ESR1 wild-type and mutant breast cancer, enhances combination activity with standard-of-care agents, and inhibits growth of ER+ intracranial tumors.

Efficacy and Safety of CDK4/6 Inhibitors: A Focus on HR+/HER2- Early Breast Cancer

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have revolutionized the treatment of hormone-receptor positive (HR+), HER2 negative (HER2-) metastatic breast cancer, and are now also established agents in the treatment of high-risk and intermediate-risk HR+ early breast cancer. Several strategies regarding CDK4/6i combinations or continuation beyond progression have been successfully evaluated in the metastatic setting, and are considered a standard of care. Mechanism of action of and resistance mechanisms against CDK4/6i in addition to endocrine resistance represent an important research topic, important for the treatment of HR+ breast cancer. Clinically, CDK4/6i are efficient substances that are usually well tolerated. However, side effects differing between the substances have been reported, and might lead to treatment discontinuation, including in the early disease setting. In the adjuvant setting, the addition of palbociclib to standard endocrine treatment has not improved outcomes, whereas large randomized phase III trials have demonstrated significant disease-free survival benefit for the addition of ribociclib (NATALEE trial) and abemaciclib (monarchE trial). Patient selection, treatment duration, endocrine backbone therapy, and other study details differ between these pivotal trials. This review focuses on both the scientific background as well as all available clinical data of CDK4/6i, with particular emphasis on their use in early breast cancer.

Hematological toxicity of cyclin-dependent kinase 4/6 inhibitors in patients with breast cancer: a network meta-analysis and pharmacovigilance study

OBJECTIVES

We aimed to evaluate and compare the risk of hematological adverse events (AEs) associated with CDK4/6 inhibitors using data from randomized controlled trials (RCTs) and Food and Drug Adverse Event Reporting System (FAERS) database.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched for RCTs related to abemaciclib, palbociclib, and ribociclib. A network meta-analysis (NMA) was conducted to compare the risks of hematological AEs, and a disproportionality analysis was performed to detect signals of hematological AEs.

RESULTS

16 RCTs comprising 16,350 breast cancer patients were included. Palbociclib and ribociclib had similar risks for hematological AEs, except a higher risk of grade 3-4 leukopenia observed with palbociclib (risk ratio [RR]: 7.84, 95% confidence interval [95%CI]: 1.33-41.28). Abemaciclib had a higher risk of anemia than both ribociclib (grade 1-4: RR: 2.23, 95% CI: 1.25 - 3.96; grade 3-4: RR: 3.52, 95% CI: 1.59 - 8.11) and palbociclib (grade 1-4: RR: 1.65, 95%CI: 1.03 - 2.59), but a lower risk of grade 3-4 of both leukopenia (RR: 0.12, 95%CI: 0.02 - 0.49) and neutropenia (RR: 0.15, 95%CI: 0.04 - 0.52) compared with palbociclib. Signals indicating occurrence of leukopenia, neutropenia, anemia, and thrombocytopenia were identified for three CDK4/6 inhibitors.

CONCLUSION

Abemaciclib, palbociclib, and ribociclib showed significant but inconsistent hematological toxicity risks.

A phase III trial of adjuvant ribociclib plus endocrine therapy versus endocrine therapy alone in patients with HR-positive/HER2-negative early breast cancer: final invasive disease-free survival results from the NATALEE trial

BACKGROUND

NATALEE assessed efficacy and tolerability of 3 years of adjuvant ribociclib plus a nonsteroidal aromatase inhibitor (NSAI) compared with an NSAI alone in a broad population of patients with hormone receptor (HR)-positive/human epidermal growth factor 2 (HER2)-negative early breast cancer, including a select group without nodal involvement. This is the final preplanned analysis of invasive disease-free survival (iDFS).

PATIENTS AND METHODS

Premenopausal/postmenopausal women and men were randomized 1 : 1 to ribociclib (n = 2549; 400 mg/day, 3 weeks on/1 week off for 36 months) plus NSAI (letrozole 2.5 mg/day or anastrozole 1 mg/day for 60 months) or NSAI alone (n = 2552). Men and premenopausal women also received goserelin (3.6 mg once every 28 days). Patients had anatomical stage IIA (N0 with additional risk factors or N1), IIB, or III disease. The primary endpoint was iDFS. Secondary efficacy endpoints were recurrence-free survival (RFS), distant DFS, and overall survival. This final iDFS analysis was planned after ∼500 events.

RESULTS

At data cut-off (21 July 2023), ribociclib was stopped for 1996 patients (78.3%); 1091 (42.8%) completed 3 years of ribociclib, and ribociclib treatment was ongoing for 528 (20.7%). Median follow-up for iDFS was 33.3 months. Overall, 226 and 283 iDFS events occurred with ribociclib plus NSAI versus NSAI alone, respectively. Ribociclib plus NSAI demonstrated significant iDFS benefit over NSAI alone [hazard ratio 0.749, 95% confidence interval (CI) 0.628-0.892; P = 0.0012]. The 3-year iDFS rates were 90.7% (95% CI 89.3% to 91.8%) versus 87.6% (95% CI 86.1% to 88.9%). A consistent benefit was observed across prespecified subgroups, including stage (II/III) and nodal status (positive/negative). Distant DFS and RFS favored ribociclib plus NSAI. Overall survival data were immature. No new safety signals were observed.

CONCLUSIONS

With longer follow-up and most patients off ribociclib, NATALEE continues to demonstrate iDFS benefit with ribociclib plus NSAI over NSAI alone in the overall population and across key subgroups. Observed adverse events remained stable.

High Ki67 expression, HER2 overexpression, and low progesterone receptor levels in high-grade DCIS: significant associations with clinical practice implications

Simple summary

We investigated the role of Ki67, a ubiquitous marker in cancer, within the context of ductal carcinoma in situ (DCIS), a precursor of invasive breast cancer. Through rigorous analysis of histopathological and immunopathological samples from a substantial cohort, this study revealed robust correlations between heightened Ki67 expression, diminished progesterone (PR) levels, and HER2 overexpression, indicative of aggressive DCIS phenotypes. These findings offer novel insights into the surrogate immunomolecular subtyping landscape of DCIS, potentially refining risk stratification and therapeutic approaches. This elucidation underscores the translational significance of Ki67 as a prognostic and predictive biomarker in DCIS, with implications for personalized treatment paradigms and patient outcomes.

Background

The Ki67 proliferation index is widely used in various tumors, including invasive breast carcinoma (IBC). However, its prognostic utility is often constrained by technical complexity. Its diagnostic and clinical significance in ductal carcinoma in situ (DCIS) remains uncertain. We studied Ki67 immunohistochemistry interobserver diagnostic agreement at different cutoff values in high-grade DCIS. Additionally, we investigated the associations between Ki67 expression, PR levels, and human epidermal growth factor receptor 2 (HER2) in high-grade DCIS among various subtypes (Luminal (Lum) A, LumB HER2-, LumB HER2+, HER2-enriched, and triple-negative)).

Methods

Using histopathological specimens from 484 patients diagnosed with DCIS between 1996 and 2018, we implemented the 2013 St. Gallen recommendations for surrogate immunomolecular subtyping of IBC. Subtypes were classified, and the Ki67 interobserver diagnostic agreement between Counting Pathologist 1 (CP1) and CP2 was calculated using Cohen's kappa coefficient at various cutoff values.

Results

The Cohen's kappa coefficient for interobserver agreement between CP1 and CP2 was κ = 0.586, indicating moderate agreement. Ki67 levels varied significantly among subtypes (p < 0.0001), with a median Ki67% being higher in cases with invasive components (p = 0.0351). Low PR combined with high Ki67% was significantly associated with HER2 overexpression (p = 0.0107).

Conclusions

Interobserver agreement for the Ki67 count was moderate. Ki67 expression showed considerable variability in high-grade DCIS. Low PR levels combined with high Ki67 expression were linked to HER2 overexpression, showing possible clinical implications for identifying high-risk DCIS.

Adjuvant endocrine therapy with cyclin-dependent kinase 4/6 inhibitor, ribociclib, for localized hormone receptor-positive/HER2- breast cancer (LEADER)

Optimal timing and dosing of adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitor in early breast cancer is controversial. This prospective phase II clinical trial investigated tolerability and safety of two ribociclib dosing schedules. Patients with stage I-III hormone receptor-positive (HR+)/HER2- breast cancer on adjuvant endocrine therapy (ET) were randomized to two ribociclib dosing schedules: 400 mg continuous vs 600 mg intermittent, with initiation in early (prior ET < 2 years) vs delayed (prior ET ≥ 2 years) setting. Primary objective was to evaluate safety and tolerability of continuous vs intermittent schedule. Primary endpoint was proportion of patients who discontinued ribociclib before completion of all 12 cycles (measured at 12 months). Recurrence free survival (RFS) and circulating tumor DNA (ctDNA) detection were also evaluated. 81 patients were enrolled. Only six serious adverse events occurred, with no significant difference between treatment arms and no subject deaths. Twenty-five patients (31%) discontinued ribociclib before completion of 12 months, with no significant difference between treatment arms. Ribociclib discontinuation was higher in early vs delayed initiation (36% vs 21%). At median follow-up of 20 months, two patients in the intermittent arm (600 mg; Arm 2) experienced disease recurrence (2-year RFS 97%, 95%CI 88-99%), vs none in the continuous arm (400 mg; Arm 1) (2-year RFS 100%). ctDNA was only identified in the two subjects with recurrent disease at median of 7.5 months prior to radiological recurrence. Ribociclib is a safe and well-tolerated adjunct to adjuvant ET in early-stage breast cancer. Delayed initiation of ribociclib at 400 mg continuous dosing was feasible, better tolerated and associated with promising outcomes. ctDNA detection preceded clinical evidence of recurrence and may be considered as a surveillance tool in breast cancer.

Consensus Guidelines for the Use of Cyclin-Dependent Kinase (CDK) 4/6 Inhibitors in the Management of Hormone Receptor Positive (HR+ve), Her2-ve Early Breast Cancer (EBC)

It is still not possible for all patients with early breast cancer to be cured. Even when they respond well to initial therapy, there exists a substantial risk for recurrence, sometimes after several years. With the availability of cyclin-dependent kinase (CDK) 4/6 inhibitors the role of adjuvant therapy has improved, and so has the chance of cure. These consensus guidelines will ensure that the community oncologist will be able to take the right decision for their patient. The expert committee shares their real-world experience as well as the consensus voting results. Patients eligible for adjuvant therapy with CDK4/6 inhibitors should start that treatment at the earliest. Based on current published data, abemaciclib is the preferred CDK4/6 inhibitor that should be used in eligible patients (unless contraindicated). To ensure optimal dose intensity and adherence to treatment schedule, use of literature and patient information material can improves compliance. Treatment modification requires early reporting of adverse effects, a responsibility of the patient and caregiver (relatives).

Clinical Implications of Breast Cancer Intrinsic Subtypes

Estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) breast cancers have different genomic architecture and show large-scale gene expression differences consistent with different cellular origins, which is reflected in the luminal (i.e., ER+) versus basal-like (i.e., ER-) molecular class nomenclature. These two major molecular subtypes have distinct epidemiological risk factors and different clinical behaviors. Luminal cancers can be subdivided further based on proliferative activity and ER signaling. Those with a high expression of proliferation-related genes and a low expression of ER-associated genes, called luminal B, have a high risk of early recurrence (i.e., within 5 years), derive significant benefit from adjuvant chemotherapy, and may benefit from adding immunotherapy to chemotherapy. This subset of luminal cancers is identified as the genomic high-risk ER+ cancers by the MammaPrint, Oncotype DX Recurrence Score, EndoPredict, Prosigna, and several other molecular prognostic assays. Luminal A cancers are characterized by low proliferation and high ER-related gene expression. They tend to have excellent prognosis with adjuvant endocrine therapy. Adjuvant chemotherapy may not improve their outcome further. These cancers correspond to the genomic low-risk categories. However, these cancers remain at risk for distant recurrence for extended periods of time, and over 50% of distant recurrences occur after 5 years. Basal-like cancers are uniformly highly proliferative and tend to recur within 3-5 years of diagnosis. In the absence of therapy, basal-like breast cancers have the worst survival, but these also include many highly chemotherapy-sensitive cancers. Basal-like cancers are often treated with preoperative chemotherapy combined with an immune checkpoint inhibitor which results in 60-65% pathologic complete response rates that herald excellent long-term survival. Patients with residual cancer after neoadjuvant therapy can receive additional postoperative chemotherapy that improves their survival. Currently, there is no clinically actionable molecular subclassification for basal-like cancers, although cancers with high androgen receptor (AR)-related gene expression and those with high levels of immune infiltration have better prognosis, but currently their treatment is not different from basal-like cancers in general. A clinically important, minor subset of breast cancers are characterized by frequent HER2 gene amplification and high expression of a few dozen genes, many residing on the HER2 amplicon. This is an important subset because of the highly effective HER2 targeted therapies which are synergistic with endocrine therapy and chemotherapy. The clinical behavior of HER2-enriched cancers is dominated by the underlying ER subtype. ER+/HER2-enriched cancers tend to have more indolent course and lesser chemotherapy sensitivity than their ER counterparts.

Efficacy of radiotherapy for bone metastasis in breast cancer patients treated with cyclin-dependent kinase 4/6 inhibitors

BACKGROUND

In patients diagnosed withestrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, bone metastasesemerge as theprimary siteofsignificant tumor burden. Cyclin-dependent kinase 4/6 (CDK4/6i) inhibitorsare thegold standard in this clinical scenario, while radiotherapy (RT) represents a valuable addition. However, data on the efficacy of this combination remain scarce. We aimed to evaluate efficacy of RT in bone metastatic breast cancer patients treated with CDK4/6 inhibitors.

MATERIALS AND METHODS

398 patients (pts) with ER-positive HER2-negative breast cancer with bone metastases treated with CDK4/6i between 2018-2024 were analyzed. A total of 114 pts received 177 bone RT concurrently with CDK4/6i or within 6 months before CDK4/6i initiation, including 34 courses of stereotactic-body RT and 143 courses of conventional RT.

RESULTS

The median progression-free survival (PFS) in pts who received bone RT was 31.0 months, compared to 26.3 months in pts without bone RT. The 2-y PFS for pts with bone RT was 57.1 % [95 % CI: 46.3-66.6 %] vs. 53.2 % [95 % CI: 46.3-59.6 %] for patients without bone RT (p = 0.51). The median overall survival (OS) for pts who received bone RT was 49.1 months, compared to 40.5 months for pts without bone RT. The 3-y OS for pts with bone RT was 63.7 % [95 % CI: 51.5-73.5 %] vs. 55.0 % [95 % CI 46.6-62.6 %] for pts without bone RT (p = 0.50). The 3-y local control for irradiated patients was 86.9 % [95 % CI 72.2-94.1 %].

CONCLUSIONS

In this study, we present the largest cohort published to date of breast cancer patients who received CDK4/6i alongside bone-directed RT. Although the observed differences in survival were not statistically significant, RT remains a viable treatment modality in metastatic breast cancer in some patients.

Predictive factors for complete pathologic response in luminal breast cancer: impact of ki67 and HER2 low expression

Background

Complete pathological response to neoadjuvant treatment (NAT) in breast cancer is associated with prolonged survival. Compared to other breast cancer immunophenotypes, luminal tumors are the least chemosensitive with low rates of pathological response within this molecular subtype. Thus, finding predictors of response in this subset remains challenging. The emerging concept of low human epidermal growth factor receptor 2 (HER2) expression has led to a repurpose of the current prognostic system. Little is known about its correlation with response to NAT.

Objectives

This study aims to evaluate predictors of response in early-stage luminal breast cancer receiving neoadjuvant chemotherapy.

Design

A total of 252 luminal patients who received NAT were retrospectively assessed in this cohort study.

Methods

We analyzed the correlation of ki67 and HER2 low expression with the rate of pathologic response. Using ki67 as a continuous variable and applying the receiver operating characteristic curves method.

Results

We identified that in patients with a ki67 expression level >37%, the probability of having a complete pathological response was 4.80 times higher (odds ratio = 4.80, 95% confidence interval: 1.92-12.04). In Her2-low breast cancer patients, Her2 expression did not correlate with a better response rate.

Conclusion

In our study, a ki67 expression value greater than 37% constitutes a predictive biomarker of pathological complete response in the subgroup of patients with luminal B tumors and could be considered, therefore, an indicator for treatment decisions in this subgroup.

Characteristics, treatment patterns and survival of patients with high-risk early hormone receptor-positive breast cancer in French real-world settings: an exploratory study of the CANTO cohort

BACKGROUND

Patients with hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer (HR+ BC) with unfavorable features have an increased risk of relapse and are currently candidate for additional treatment strategies. We evaluated the real-world clinicopathological characteristics, treatment patterns and survival outcomes of these patients within the CANcer TOxicities study (CANTO, NCT01993498).

PATIENTS AND METHODS

This is a retrospective analysis of the prospective data collected within CANTO between 2012 and 2022. Patients with high-risk HR+ BC were defined either by the identification of at least four positive axillary lymph nodes (LNs) or one to three positive axillary LNs with a tumor size ≥5 cm or histologic grade 3 (cohort 1). The definition 1-3 positive LNs with Ki-67 ≥20% was also considered (cohort 2). The Kaplan-Meier method was used for survival analysis.

RESULTS

Patients with high-risk HR+ BC represented 15.0%-19.6% of HR+ BC (cohort 1 and 2, respectively) in the CANTO cohort. Of the 1266 patients in cohort 1, 617 patients (49.0%) had ≥4 LNs, 327 (26.0%) had tumor ≥5 cm and 727 (57.6%) had grade III tumors. 79.9% had a favorable Charlson comorbidity score and 88.1% stage II/IIIA. Patients with ≥10 LNs accounted for 11.8%. (Neo)adjuvant chemotherapy was administered in 94.2%. Endocrine therapy was prescribed in 97.3%, mostly with aromatase inhibitors and discontinued in 34.3%, mainly for adverse events. Patients enrolled at least 6 years before data extraction had a 5-year invasive disease-free survival and 5-year distant relapse-free survival of 79.9% [95% confidence interval (CI) 77.2% to 82.4%] and 83.5% (95% CI 80.9% to 85.7%), respectively.

CONCLUSIONS

This real-world study confirms that patients with HR+ BC and unfavorable clinicopathological features are at risk of relapse early in their adjuvant treatment trajectory, despite (neo)adjuvant chemotherapy. It is imperative to implement innovative treatment approaches for high-risk patients, ideally adding them as early as possible to the adjuvant treatment.

Clinical Relevance of TP53 Mutation and Its Characteristics in Breast Cancer with Long-Term Follow-Up Date

BACKGROUND

The TP53 mutation is one of the most frequently identified mutations in human cancers and is typically associated with a poor prognosis. However, there are conflicting findings regarding its impact. We aimed to clarify the clinical relevance of TP53 mutations across all breast cancer subtypes and treatments utilizing long-term follow-up data.

METHODS

We retrospectively identified the data of breast cancer patients who underwent TP53 mutation testing. Stratified log-rank tests and Cox regression analysis were performed to compare oncologic outcomes based on TP53 mutation status and the characteristics of these mutations, including types and locations. Mutations in exons 5-9 were identified using polymerase chain reaction-denaturing high-performance liquid chromatography (PCR-DHPLC) and direct sequencing.

RESULTS

Between January 2007 and December 2015, 650 breast cancer patients underwent TP53 mutation testing in Gangnam Severance Hospital. The TP53 mutations were identified in 172 patients (26.5%), with 34 (19.8%) exhibiting missense hotspot mutations. Patients with TP53 mutations (TP53-mutated group) had worse prognosis, demonstrated by a 10-year recurrence-free survival (RFS) rate of 83.5% compared to 86.6% in patients without mutations (HR, 1.67; p = 0.026) and a 10-year overall survival (OS) rate of 88.1% versus 91.0% (HR, 3.02; p = 0.003). However, subgroup analyses within the TP53-mutated group did not reveal significant differences in oncologic outcomes based on mutation types and locations.

CONCLUSIONS

Our findings establish that TP53 mutations are linked to poorer oncologic outcomes in breast cancer across all subtypes. Yet, within the TP53-mutated group, the specific characteristics of TP53 mutations do not influence oncologic outcomes.

Predicting pathologic complete response to neoadjuvant chemotherapy in breast cancer using a machine learning approach

BACKGROUND

For patients with breast cancer undergoing neoadjuvant chemotherapy (NACT), most of the existing prediction models of pathologic complete response (pCR) using clinicopathological features were based on standard statistical models like logistic regression, while models based on machine learning mostly utilized imaging data and/or gene expression data. This study aims to develop a robust and accessible machine learning model to predict pCR using clinicopathological features alone, which can be used to facilitate clinical decision-making in diverse settings.

METHODS

The model was developed and validated within the National Cancer Data Base (NCDB, 2018-2020) and an external cohort at the University of Chicago (2010-2020). We compared logistic regression and machine learning models, and examined whether incorporating quantitative clinicopathological features improved model performance. Decision curve analysis was conducted to assess the model's clinical utility.

RESULTS

We identified 56,209 NCDB patients receiving NACT (pCR rate: 34.0%). The machine learning model incorporating quantitative clinicopathological features showed the best discrimination performance among all the fitted models [area under the receiver operating characteristic curve (AUC): 0.785, 95% confidence interval (CI): 0.778-0.792], along with outstanding calibration performance. The model performed best among patients with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer (AUC: 0.817, 95% CI: 0.802-0.832); and by adopting a 7% prediction threshold, the model achieved 90.5% sensitivity and 48.8% specificity, with decision curve analysis finding a 23.1% net reduction in chemotherapy use. In the external testing set of 584 patients (pCR rate: 33.4%), the model maintained robust performance both overall (AUC: 0.711, 95% CI: 0.668-0.753) and in the HR+/HER2- subgroup (AUC: 0.810, 95% CI: 0.742-0.878).

CONCLUSIONS

The study developed a machine learning model ( https://huolab.cri.uchicago.edu/sample-apps/pcrmodel ) to predict pCR in breast cancer patients undergoing NACT that demonstrated robust discrimination and calibration performance. The model performed particularly well among patients with HR+/HER2- breast cancer, having the potential to identify patients who are less likely to achieve pCR and can consider alternative treatment strategies over chemotherapy. The model can also serve as a robust baseline model that can be integrated with smaller datasets containing additional granular features in future research.

Prognosis prediction with the IHC3 score in patients with node-negative, hormone receptor-positive, HER2-negative early breast cancer

BACKGROUND

Prognostication has been used to identify patient populations that could potentially benefit from treatment de-escalation. In patients with hormone receptor-positive (HRpos), human epidermal growth factor receptor 2-negative (HER2neg) early breast cancer (eBC), treatment de-escalation classically involved omitting chemotherapy. With recently developed specialized therapies that require hands-on side-effect management, the therapeutic landscape is changing and therapy decisions are no longer based only on prognosis, but also consider potential side-effects. Therefore, identification of patient groups based on prognostication has gained importance.

MATERIALS AND METHODS

In this retrospective analysis, a population of 2359 node-negative HRpos/HER2neg eBC patients was selected from all patients treated at the University Breast Center of Franconia, Germany between 2002 and 2021. The prognostic value of the IHC3 score (incorporating immunohistochemical measurements of the estrogen and progesterone receptor status and Ki-67) with clinical parameters (lymph node status, tumor stage, grading) regarding invasive disease-free survival (iDFS) and overall survival (OS) was assessed.

RESULTS

IHC3 positively correlated with Ki-67 expression and inversely correlated with hormone receptor expression. IHC3 categorized into quartiles identified patients with a more unfavorable prognosis: 5-year and 10-year iDFS rates for patients in the highest versus the lowest quartile were 84% versus 95% and 70% versus 88%, respectively. A sensitivity analysis of distant disease-free survival showed similar results to those of iDFS. Five-year and 10-year OS rates for patients in the highest versus the lowest quartile were, respectively, 92% versus 97% and 81% versus 92%.

CONCLUSIONS

IHC3 is able to define prognostic groups in patients with node-negative, HRpos/HER2neg eBC. Node-negative patients with a high IHC3 score had the worst prognosis, which was comparable to that of node-positive patients described in recent trials. This simple and cost-effective tool could thus potentially aid in identifying patient groups for innovative therapeutic approaches.

Abemaciclib combined with endocrine therapy as adjuvant treatment for hormone-receptor-positive, HER2-, high-risk early breast cancer: 5-year Chinese population analysis of the phase III randomized monarchE study

Background

Abemaciclib was the first cyclin-dependent kinase 4/6 (CDK4/6) inhibitor approved globally in the adjuvant setting for high-risk hormone-receptor positive (HR+)/human epidermal growth factor 2 negative (HER2-) early breast cancer (EBC), based on the phase III monarchE trial.

Objective

To report an exploratory Chinese population analysis based on the preplanned overall survival (OS) interim analysis with 5-year efficacy results of monarchE.

Design and methods

Patients with HR+/HER2-, high-risk (⩾4 positive lymph nodes, or 1-3 nodes and either tumor size ⩾5 cm, histologic grade 3, or Ki-67 ⩾20%) EBC were randomized (1:1) to abemaciclib (150 mg twice daily for 2 years) plus endocrine therapy (ET), or ET alone. This analysis included Chinese patients enrolled in mainland China, Hong Kong, and Taiwan. The primary endpoint was invasive disease-free survival (IDFS); key secondary endpoints included distant relapse-free survival (DRFS), safety, and patient-reported outcomes (PROs).

Results

Overall, 501 Chinese patients were included (abemaciclib + ET, n = 259; ET, n = 242). With a median follow-up of 53 months, the addition of abemaciclib to ET resulted in improvements in IDFS (estimated 5-year IDFS rate: 85.9% vs 79.1%; hazard ratio (HR), 0.65 (95% confidence interval (CI) 0.41-1.03)) and DRFS (estimated 5-year DRFS rate: 88.4% vs 82.3%; HR, 0.65 (95% CI, 0.39-1.07)). The most common grade ⩾3 treatment-emergent adverse events in the abemaciclib + ET versus ET groups were neutropenia (24.7% vs 0.8%) and leukopenia (22.4% vs 0.4%). Generally, no clinically meaningful difference in PROs (endocrine symptoms and fatigue) was observed between groups, except for diarrhea.

Conclusion

At this prespecified OS interim analysis, which provides 5-year data, the addition of abemaciclib to ET in Chinese patients with high-risk HR+, HER2- EBC was associated with sustained and clinically meaningful improvements in IDFS and DRFS, with acceptable safety and tolerability profiles and minimal impact on PROs. These results represent the first full report of a CDK4/6 inhibitor in Chinese patients with EBC and support the positive benefit-risk profile of adjuvant abemaciclib + ET in Chinese patients.

Trial registration

ClinicalTrials.gov identifier: NCT03155997 (first posted: May 16, 2017).

Hormones as a double-edged sword: the role of hormones in cancer progression and the potential of targeted hormone therapies

Cancer remains a significant cause of mortality in the world, with increasing prevalence worldwide. There are numerous treatments ranging from surgery to chemotherapy and radiotherapy, but since cancer is a heterogeneous disease, only few patients possibly respond to treatments. However, it opens a huge space for the advent of targeted therapies such as hormone therapy, immunotherapy, and target-specific drugs. Hormonal therapy using hormone agonists/antagonists or hormone receptor inhibitors-called the next-generation hormonal agents-hits distinct hormonal pathways that are involved in breast, prostate and ovarian cancer. Preliminary results show that through combination of drugs, it is possible that the synergistic effects may actually lead to better survival than with the use of single drugs. With manageable adverse effects, hormonal therapy offers much hope for treatment of this rather challenging malignancy of the hormone-sensitive cancers, especially in combination with other treatments.

Updates in Systemic Treatment of Hormone Receptor-Positive Early-Stage Breast Cancer

OPINION STATEMENT

Hormone-receptor positive (HR +) and human epidermal growth factor receptor 2 (HER2) negative early breast cancer (eBC) is a heterogeneous disease with several contributing factors for increased risk of recurrence, including tumor features, individual biomarkers, and genomic risk. The current standard approach in the management of HR + /HER2neg eBC includes chemotherapy and endocrine therapy (ET), and additional therapies based on risk profile, menopausal status, and genetics are sometimes appropriate. The risk of recurrence is more pronounced in patients with high-risk eBC including large tumor size, nodal involvement, high proliferative index, and genetic predisposition. In premenopausal patients with high-risk eBC, ovarian function suppression in combination with adjuvant ET improves survival. In postmenopausal patients, extended aromatase inhibitor (AI) therapy can be considered. Recent trials have identified novel treatment approaches to reduce the risk of recurrence in high-risk HR + /HER2neg eBC including the addition of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors to adjuvant ET. For patients with germline BRCA1/BRCA2 mutations, adjuvant poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors have been shown to improve overall survival (OS). However, despite these recent advances, the risk of recurrence remains substantial, highlighting an area of unmet need. There are several ongoing clinical trials further investigating the role of CDK 4/6 inhibitors and immunotherapy in high-risk HR + /HER2neg eBC.

Neoadjuvant letrozole and palbociclib in patients with HR-positive/HER2-negative early breast cancer and Oncotype DX Recurrence Score ≥18: DxCARTES study

BACKGROUND

The effect of the addition of cyclin-dependent kinases 4 and 6 inhibitors to endocrine therapy in terms of molecular downstaging remains undetermined. Switching from a high-risk to a low risk Recurrence Score (RS) group could provide useful information to identify patients who might not require chemotherapy. The purpose of this study was to assess the biological and clinical activity of letrozole plus palbociclib as neoadjuvant treatment for patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer with an initial Oncotype DX RS ≥18.

PATIENTS AND METHODS

Participants were women aged ≥18 years with HR-positive/HER2-negative, Ki67 ≥ 20%, stage II-IIIB early breast cancer with a baseline RS ≥18. Eligible patients with a pretreatment RS 18-25 (cohort A) and 26-100 (cohort B) received six 28-day cycles of letrozole (2.5 mg per day; plus goserelin if pre- or perimenopausal) plus palbociclib (125 mg per day; 3/1 schedule) before surgery. The primary endpoint for both cohorts was the proportion of patients who achieved an RS ≤25 at surgery or a pathological complete response (pCR).

RESULTS

A total of 67 patients were enrolled, among which 65 were assessable for the primary endpoint (32 patients in cohort A and 33 in cohort B). At surgery, 22 (68.8%) patients in cohort A and 18 (54.5%) patients in cohort B had an RS ≤25 or a pCR [only 1 (3.0%) patient in cohort B], meeting the primary endpoint in cohort B (P < 0.01), but not in cohort A (P = 0.98). No new safety signals were identified.

CONCLUSIONS

The efficacy of neoadjuvant treatment with letrozole plus palbociclib does not seem to depend on pretreatment RS for patients with RS ≥18. However, around half of patients with HR-positive/HER2-negative early breast cancer with an RS 26-100 at baseline achieved molecular downstaging with this regimen.

Prognostic impact of selection criteria of current adjuvant endocrine therapy trials NATALEE and monarchE in postmenopausal HRpos/HER2neg breast cancer patients treated with upfront letrozole

BACKGROUND

The monarchE and NATALEE trials demonstrated the benefit of CDK4/6 inhibitor (CDK4/6i) therapy in adjuvant breast cancer (BC) treatment. Patient selection, based on clinical characteristics, delineated those at high (monarchE) and high/intermediate recurrence risk (NATALEE). This study employed a historical patient cohort to describe the proportion and prognosis of patients eligible for adjuvant CDK4/6i trials.

METHODS

Between 2009 and 2011, 3529 patients were enrolled in the adjuvant PreFace clinical trial (NCT01908556). Eligibility criteria included postmenopausal patients with hormone receptor-positive (HRpos) BC for whom a five-year upfront therapy with letrozole was indicated. Patients were categorized into prognostic groups according to monarchE and NATALEE inclusion criteria, and their invasive disease-free survival (iDFS) and overall survival (OS) were assessed.

RESULTS

Among 2891 HRpos patients, 384 (13.3 %) met the primary monarchE inclusion criteria. The majority (n = 261) qualified due to having ≥ 4 positive lymph nodes. For NATALEE, 915 out of 2886 patients (31.7 %) met the eligibility criteria, with 126 patients (13.7 %) being node-negative. Patients from monarchE with ≥ 4 positive lymph nodes and NATALEE with stage III BC exhibited the poorest prognosis (3-year iDFS rate 0.87). Patients ineligible for the trials demonstrated prognoses similar to the most favorable patient groups within the eligibility criteria.

CONCLUSION

Patient populations eligible for monarchE and NATALEE trials differed. Nearly a third of the postmenopausal HRpos population, previously under upfront letrozole treatment, met the NATALEE prognostic eligibility criteria. As certain eligible groups had a prognosis similar to non-eligible patients, it might be interesting to explore additional patient groups for CDK4/6i therapy.

Completion axillary lymph node dissection for the identification of pN2-3 status as an indication for adjuvant CDK4/6 inhibitor treatment: a post-hoc analysis of the randomised, phase 3 SENOMAC trial

BACKGROUND

In luminal breast cancer, adjuvant CDK4/6 inhibitors (eg, abemaciclib) improve invasive disease-free survival. In patients with T1-2, grade 1-2 tumours, and one or two sentinel lymph node metastases, completion axillary lymph node dissection (cALND) is the only prognostic tool available that can reveal four or more nodal metastases (pN2-3), which is the only indication for adjuvant abemaciclib in this setting. However, this technique can lead to substantial arm morbidity in patients. We aimed to pragmatically describe the potential benefit and harm of this strategy on the individual patient level in patients from the ongoing SENOMAC trial.

METHODS

In the randomised, phase 3, SENOMAC trial, patients aged 18 years or older, of any performance status, with clinically node-negative T1-T3 breast cancer and one or two sentinel node macrometastases from 67 sites in five European countries (Denmark, Germany, Greece, Italy, and Sweden) were randomly assigned (1:1), via permutated block randomisation (random block size of 2 and 4) stratified by country, to either cALND or its omission (ie, they had a sentinel lymph node biopsy only). The primary outcome is overall survival, which is yet to be reported. In this post-hoc analysis, patients from the SENOMAC per-protocol population, with luminal oestrogen-receptor positive, HER2-negative, T1-2, histological grade 1-2 breast cancer, with tumour size of 5 cm or smaller were selected to match the characteristics of cohort 1 of the monarchE trial who would only have an indication for adjuvant abemaciclib if found to have 4 or more nodal metastases. The primary study objective was to determine the number of patients who developed patient-reported severe or very severe impairment of physical arm function after cALND (as measured by the Lymphedema Functioning, Disability, and Health [Lymph-ICF] Questionnaire) 1 year after surgery to avoid one invasive disease-free survival event at 5 years with 2 years of adjuvant abemaciclib, using invasive disease-free survival event data from cohort 1 of the monarchE trial. The SENOMAC trial is registered with ClincialTrials.gov, NCT02240472, and is closed to accrual and ongoing.

FINDINGS

Between Jan 31, 2015, and Dec 31, 2021, 2766 patients were enrolled in SENOMAC and randomly assigned to cALND (n=1384) or sentinel node biopsy only (n=1382), of whom 2540 were included in the per-protocol population. 1705 (67%) of 2540 patients met this post-hoc study's eligibility criteria, of whom 802 (47%) had a cALND and 903 (53%) had a sentinel lymph node biopsy only. Median age at randomisation was 62 years (IQR 52-71), 1699 (>99%) of 1705 patients were female, and six (<1%) were male. Among 1342 patients who responded to questionnaires, after a median follow-up of 45·2 months (IQR 25·6-59·8; data cutoff Nov 17, 2023), patient-reported severe or very severe impairment of physical arm function was reported in 84 (13%) of 634 patients who had cALND versus 30 (4%) of 708 who had sentinel lymph node biopsy only (χ2 test p<0·0001). To avoid one invasive disease-free survival event at 5 years with adjuvant abemaciclib, cALND would need to be performed in 104 patients, and would result in nine patients having severe or very severe impairment of physical arm function 1 year after surgery.

INTERPRETATION

As a method to potentially identify an indication for abemaciclib, and subsequently avoid invasive disease-free survival events at 5 years with 2 years of adjuvant abemaciclib, cALND carries a substantial risk of severe or very severe arm morbidity and so cALND should be discouraged for this purpose.

FUNDING

Swedish Research Council, the Swedish Cancer Society, the Nordic Cancer Union, and the Swedish Breast Cancer Association.

Cost-effectiveness of early vs delayed use of abemaciclib combination therapy for patients with high-risk hormone receptor-positive/human epidermal growth factor receptor 2-negative early breast cancer

BACKGROUND

Abemaciclib was newly approved for hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) high-risk early breast cancer (EBC). Clinical guidelines recommended abemaciclib as the first-line treatment for HR+/ HER2- EBC (early use) or HR+/ HER2- metastatic breast cancer (MBC) (delayed use).

OBJECTIVE

To compare the cost-effectiveness of early vs delayed use of abemaciclib for treatment of HR+/HER2- high-risk EBC. Early use was defined as combined abemaciclib and endocrine therapy as first-line therapy for EBC, followed by treatment with fulvestrant for MBC. Delayed use was defined as endocrine therapy for EBC, followed by combined abemaciclib and fulvestrant therapy for MBC.

METHODS

A 5-state model was developed to estimate lifetime costs, life-years (LYs), and quality-adjusted life-years (QALYs) of hypothetical patients with HR+/ HER2- EBC from a third-party US payer's perspective. Key clinical and safety data were derived from the monarchE and MONARCH 2 clinical trials. Costs, utilities, and disutility values of adverse events were obtained from the literature. We calculated the incremental cost-effectiveness ratio (ICER) of early vs delayed abemaciclib use and compared it with a willingness-to-pay (WTP) threshold of $100,000 per LY or QALY. Deterministic and probabilistic sensitivity analyses (PSAs) were performed to test the robustness of the base-case model.

RESULTS

Base-case analysis showed early use yielded 21.08 LYs and 17.93 QALYs for $586,213 and delayed use yielded 11.14 LYs and 9.38 QALYs for $157,576. The ICER of early vs delayed use was $43,136/LY and $50,104/QALY, which was cost-effective at the WTP threshold of $100,000. The PSA result indicated that a 94.6% likelihood of early use (vs delayed use) was cost-effective at the WTP threshold of $100,000 per QALY.

CONCLUSIONS

This study suggests that giving abemaciclib in the early stage rather than waiting until patients develop metastatic disease (current standard of care in MBC) is a cost-effective strategy.

Practical Guidance on Abemaciclib in Combination with Adjuvant Endocrine Therapy for Treating Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative High-Risk Early Breast Cancer

The most common subtype of breast cancer is hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer, accounting for 65-70% of all breast cancer cases diagnosed in the United States. Until 2015, single-agent endocrine therapy (ET) was the recommended first-line treatment for metastatic HR-positive, HER2-negative breast cancer. However, the paradigm has since shifted, as targeted therapy is now recommended in combination with ET. The cyclin-dependent kinase (CDK) 4/6 inhibitors have revolutionized the treatment of this breast cancer subtype, and combining either palbociclib, ribociclib, or abemaciclib with ET is now the standard first-line treatment for metastatic disease. Results of clinical trials in the metastatic setting have demonstrated that treatment with the combination of a CDK4/6 inhibitor and ET rather than ET alone is associated with longer overall survival, longer progression-free survival, and better objective response rates. Each of the CDK4/6 inhibitors has been investigated in combination with ET in patients with early-stage HR-positive, HER2-negative breast cancer who are at high risk of relapse. In October 2021, abemaciclib was the first CDK4/6 inhibitor approved in combination with ET by the US Food and Drug Administration for adjuvant treatment of patients with HR-positive, HER2-negative, high-risk early breast cancer. Herein, we provide practical guidance on the use of abemaciclib in combination with ET for HR-positive, HER2-negative, high-risk early breast cancer to assist clinicians in their day-to-day practice, and we review clinically relevant topics of dosing, side effect management, sequencing and optimal timing for initiation, and patient selection.

The Ki67 dilemma: investigating prognostic cut-offs and reproducibility for automated Ki67 scoring in breast cancer

PURPOSE

Quantification of Ki67 in breast cancer is a well-established prognostic and predictive marker, but inter-laboratory variability has hampered its clinical usefulness. This study compares the prognostic value and reproducibility of Ki67 scoring using four automated, digital image analysis (DIA) methods and two manual methods.

METHODS

The study cohort consisted of 367 patients diagnosed between 1990 and 2004, with hormone receptor positive, HER2 negative, lymph node negative breast cancer. Manual scoring of Ki67 was performed using predefined criteria. DIA Ki67 scoring was performed using QuPath and Visiopharm® platforms. Reproducibility was assessed by the intraclass correlation coefficient (ICC). ROC curve survival analysis identified optimal cutoff values in addition to recommendations by the International Ki67 Working Group and Norwegian Guidelines. Kaplan-Meier curves, log-rank test and Cox regression analysis assessed the association between Ki67 scoring and distant metastasis (DM) free survival.

RESULTS

The manual hotspot and global scoring methods showed good agreement when compared to their counterpart DIA methods (ICC > 0.780), and good to excellent agreement between different DIA hotspot scoring platforms (ICC 0.781-0.906). Different Ki67 cutoffs demonstrate significant DM-free survival (p < 0.05). DIA scoring had greater prognostic value for DM-free survival using a 14% cutoff (HR 3.054-4.077) than manual scoring (HR 2.012-2.056). The use of a single cutoff for all scoring methods affected the distribution of prediction outcomes (e.g. false positives and negatives).

CONCLUSION

This study demonstrates that DIA scoring of Ki67 is superior to manual methods, but further study is required to standardize automated, DIA scoring and definition of a clinical cut-off.

An original study assessing biomarker success rate in breast cancer recurrence biomarker research

BACKGROUND

Breast cancer is the second most common cause of cancer mortality worldwide. Biomarker discovery has led to advances in understanding molecular phenotyping and thus has a great potential for precision management of this diverse disease. Despite increased interest in the biomarker field, only a small number of breast cancer biomarkers are known to be clinically useful. Therefore, it is very important to characterise the success rate of biomarkers in this field and study potential reasons for the deficit. We therefore aim to achieve quantitative characterisation of the biomarker translation gap by tracking the progress of prognostic biomarkers associated with breast cancer recurrence.

METHODS

An electronic systematic search was conducted in Medline and Embase databases using keywords and mesh headings associated with breast cancer recurrence biomarkers (1940-2023). Abstracts were screened, and primary clinical studies involving breast cancer recurrence biomarkers were selected. Upon identification of relevant literature, we extracted the biomarker name, date of publication and journal name. All analyses were performed using IBM SPSS Statistics and GraphPad prism (La Jolla, California, USA).

RESULTS

A total of 19,195 articles were identified, from which 4597 articles reported breast cancer biomarkers associated with recurrence. Upon data extraction, 2437 individual biomarkers were identified. Out of these, 23 are currently recommended for clinical use, which corresponds to only 0.94% of all discovered biomarkers.

CONCLUSIONS

This study characterised for the first time the translational gap in the field of recurrence-related breast cancer biomarkers, indicating that only 0.94% of identified biomarkers were recommended for clinical use. This denotes an evident barrier in the biomarker research field and emphasises the need for a clearer route from biomarker discovery through to implementation.

Cardiac safety of ribociclib evaluated with 24-hour rhythm Holter electrocardiogram

OBJECTIVE

We aimed to evaluate cardiac safety profile of ribociclib with 24-h rhythm Holter ECG.

MATERIAL AND METHOD

Forty-two female metastatic breast cancer patients were included in the study. Rhythm Holter ECG was performed before starting treatment with ribociclib and after 3 months of the treatment initiation.

RESULTS

The mean age of the patients was 56.36 ± 12.73. 52.4% (n = 22) of the patients were using ribociclib in combination with fulvestrant and 47.6% (n = 20) with aromatase inhibitors. None of the patients developed cardiotoxicity. When the rhythm Holter results before and in third month of the treatment were compared, there was no statistically significant difference.

CONCLUSION

This is the first study evaluating effects of ribociclib treatment on cardiac rhythm with Holter ECG. The findings suggested ribociclib has a low risk of causing early cardiotoxicity.

Fit-for-Purpose Ki-67 Immunohistochemistry Assays for Breast Cancer

New therapies are being developed for breast cancer, and in this process, some "old" biomarkers are reutilized and given a new purpose. It is not always recognized that by changing a biomarker's intended use, a new biomarker assay is created. The Ki-67 biomarker is typically assessed by immunohistochemistry (IHC) to provide a proliferative index in breast cancer. Canadian laboratories assessed the analytical performance and diagnostic accuracy of their Ki-67 IHC laboratory-developed tests (LDTs) of relevance for the LDTs' clinical utility. Canadian clinical IHC laboratories enrolled in the Canadian Biomarker Quality Assurance Pilot Run for Ki-67 in breast cancer by invitation. The Dako Ki-67 IHC pharmDx assay was employed as a study reference assay. The Dako central laboratory was the reference laboratory. Participants received unstained slides of breast cancer tissue microarrays with 32 cases and performed their in-house Ki-67 assays. The results were assessed using QuPath, an open-source software application for bioimage analysis. Positive percent agreement (PPA, sensitivity) and negative percent agreement (NPA, specificity) were calculated against the Dako Ki-67 IHC pharmDx assay for 5%, 10%, 20%, and 30% cutoffs. Overall, PPA and NPA varied depending on the selected cutoff; participants were more successful with 5% and 10%, than with 20% and 30% cutoffs. Only 4 of 16 laboratories had robust IHC protocols with acceptable PPA for all cutoffs. The lowest PPA for the 5% cutoff was 85%, for 10% was 63%, for 20% was 14%, and for 30% was 13%. The lowest NPA for the 5% cutoff was 50%, for 10% was 33%, for 20% was 50%, and for 30% was 57%. Despite many years of international efforts to standardize IHC testing for Ki-67 in breast cancer, our results indicate that Canadian clinical LDTs have a wide analytical sensitivity range and poor agreement for 20% and 30% cutoffs. The poor agreement was not due to the readout but rather due to IHC protocol conditions. International Ki-67 in Breast Cancer Working Group (IKWG) recommendations related to Ki-67 IHC standardization cannot take full effect without reliable fit-for-purpose reference materials that are required for the initial assay calibration, assay performance monitoring, and proficiency testing.

Optimal Adjuvant Chemotherapy and Targeted Therapy for Early Breast Cancer-Cyclin-Dependent Kinase 4 and 6 Inhibitors: ASCO Guideline Rapid Recommendation Update

ASCO Rapid Recommendation Updates highlight revisions to select ASCO guideline recommendations as a response to the emergence of new and practice-changing data. The rapid updates are supported by an evidence review and follow the guideline development processes outlined in the ASCO Guideline Methodology Manual. The goal of these articles is to disseminate updated recommendations, in a timely manner, to better inform health practitioners and the public on the best available cancer care options. Guidelines and updates are not intended to substitute for independent professional judgment of the treating provider and do not account for individual variation among patients. See appendix for disclaimers and other important information (Appendix 1 and Appendix 2, online only).

Palbociclib combined with endocrine treatment in hormone receptor-positive, HER2-negative breast cancer patients with high relapse risk after neoadjuvant chemotherapy: subgroup analyses of premenopausal patients in PENELOPE-B

BACKGROUND

The PENELOPE-B study demonstrated that the addition of 1-year post-neoadjuvant palbociclib to endocrine therapy (ET) in patients with high-risk early breast cancer (BC) did not improve invasive disease-free survival (iDFS) compared to placebo. Here, we report results for premenopausal women.

PATIENTS AND METHODS

Patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative BC at high risk of relapse [defined as no pathological complete response after neoadjuvant chemotherapy and a clinical, pathological stage, estrogen receptor, grading (CPS-EG) score ≥3 or 2/ypN+] were randomized to receive 13 cycles of palbociclib or placebo + standard ET. Ovarian function (OF) was evaluated by centrally assessed estradiol, follicle-stimulating hormone and anti-Müllerian hormone serum levels.

RESULTS

Overall, 616 of 1250 randomized patients were premenopausal; of these, 30.0% were <40 years of age, 47.4% had four or more metastatic lymph nodes, and 58.2% had a CPS-EG score ≥3. 66.1% of patients were treated with tamoxifen alone, and 32.9% received ovarian function suppression (OFS) in addition to either tamoxifen or aromatase inhibitor (AI). After a median follow-up of 42.8 months (97.2% completeness) no difference in iDFS between palbociclib and placebo was observed [hazard ratio = 0.95, 95% confidence interval (CI) 0.69-1.30, P = 0.737]. The estimated 3-year iDFS rate was marginally higher in the palbociclib arm (80.6% versus 78.3%). Three year iDFS was higher in patients receiving AI than tamoxifen plus OFS or tamoxifen alone (86.0% versus 78.6% versus 78.0%). Patients receiving tamoxifen plus OFS showed a favorable iDFS with palbociclib (83.0% versus 74.1%, hazard ratio = 0.52, 95% CI 0.27-1.02, P = 0.057). Hematologic adverse events were more frequent with palbociclib (76.1% versus 1.9% grade 3-4, P < 0.001). Palbociclib seems not to negatively impact the OF throughout the treatment period.

CONCLUSIONS

In premenopausal women, who received tamoxifen plus OFS as ET, the addition of palbociclib to ET results in a favorable iDFS. The safety profile seems favorable and in contrast to chemotherapy palbociclib does not impact OF throughout the treatment period.

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.

METTL1-mediated tRNA m7G methylation and translational dysfunction restricts breast cancer tumorigenesis by fueling cell cycle blockade

BACKGROUND

RNA modifications of transfer RNAs (tRNAs) are critical for tRNA function. Growing evidence has revealed that tRNA modifications are related to various disease processes, including malignant tumors. However, the biological functions of methyltransferase-like 1 (METTL1)-regulated m7G tRNA modifications in breast cancer (BC) remain largely obscure.

METHODS

The biological role of METTL1 in BC progression were examined by cellular loss- and gain-of-function tests and xenograft models both in vitro and in vivo. To investigate the change of m7G tRNA modification and mRNA translation efficiency in BC, m7G-methylated tRNA immunoprecipitation sequencing (m7G tRNA MeRIP-seq), Ribosome profiling sequencing (Ribo-seq), and polysome-associated mRNA sequencing were performed. Rescue assays were conducted to decipher the underlying molecular mechanisms.

RESULTS

The tRNA m7G methyltransferase complex components METTL1 and WD repeat domain 4 (WDR4) were down-regulated in BC tissues at both the mRNA and protein levels. Functionally, METTL1 inhibited BC cell proliferation, and cell cycle progression, relying on its enzymatic activity. Mechanistically, METTL1 increased m7G levels of 19 tRNAs to modulate the translation of growth arrest and DNA damage 45 alpha (GADD45A) and retinoblastoma protein 1 (RB1) in a codon-dependent manner associated with m7G. Furthermore, in vivo experiments showed that overexpression of METTL1 enhanced the anti-tumor effectiveness of abemaciclib, a cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor.

CONCLUSION

Our study uncovered the crucial tumor-suppressive role of METTL1-mediated tRNA m7G modification in BC by promoting the translation of GADD45A and RB1 mRNAs, selectively blocking the G2/M phase of the cell cycle. These findings also provided a promising strategy for improving the therapeutic benefits of CDK4/6 inhibitors in the treatment of BC patients.

Early Breast Cancer Risk Assessment: Integrating Histopathology with Artificial Intelligence

Effective risk assessment in early breast cancer is essential for informed clinical decision-making, yet consensus on defining risk categories remains challenging. This paper explores evolving approaches in risk stratification, encompassing histopathological, immunohistochemical, and molecular biomarkers alongside cutting-edge artificial intelligence (AI) techniques. Leveraging machine learning, deep learning, and convolutional neural networks, AI is reshaping predictive algorithms for recurrence risk, thereby revolutionizing diagnostic accuracy and treatment planning. Beyond detection, AI applications extend to histological subtyping, grading, lymph node assessment, and molecular feature identification, fostering personalized therapy decisions. With rising cancer rates, it is crucial to implement AI to accelerate breakthroughs in clinical practice, benefiting both patients and healthcare providers. However, it is important to recognize that while AI offers powerful automation and analysis tools, it lacks the nuanced understanding, clinical context, and ethical considerations inherent to human pathologists in patient care. Hence, the successful integration of AI into clinical practice demands collaborative efforts between medical experts and computational pathologists to optimize patient outcomes.

CDK4/6 Inhibition - Therapy Sequences and the Quest to Find the Best Biomarkers - an Overview of Current Programs

In recent years, new targeted therapies have been developed to treat patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer. Some of these therapies have not just become the new therapy standard but also led to significantly longer overall survival rates. The cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) have become the therapeutic standard for first-line therapy. Around 70 - 80% of patients are treated with a CDK4/6i. In recent years, a number of biomarkers associated with progression, clonal selection or evolution have been reported for CDK4/6i and their endocrine combination partners. Understanding the mechanisms behind treatment efficacy and resistance is important. A better understanding could contribute to planning the most effective therapeutic sequences and utilizing basic molecular information to overcome endocrine resistance. One study with large numbers of patients which aims to elucidate these mechanisms is the Comprehensive Analysis of sPatial, TempORal and molecular patterns of ribociclib efficacy and resistance in advanced Breast Cancer patients (CAPTOR BC) trial. This overview summarizes the latest clinical research on resistance to endocrine therapies, focusing on CDK4/6 inhibitors and discussing current study concepts.

Correlation between postoperative treatment selection and prognosis determined using the Oncotype DX® test data: a retrospective multicenter study in Japan

PURPOSE

Oncotype DX® is a frequently used multigene assay for hormone receptor-positive breast cancers. However, limited evidence is available regarding its application in Japan owing to the lack of insurance coverage. Therefore, we conducted this large-scale, retrospective study by collecting data from nine Japanese institutes and assessed postoperative treatment choice and prognosis by using Oncotype DX®.

METHODS

Six hundred thirty-two patients who underwent breast surgery and whose recurrence score (RS) data were available were included. They were divided into RS 0-25 and RS ≥ 26 groups. The groups were compared in terms of clinicopathological factors, treatment options, and prognosis.

RESULTS

After the median follow-up period of 10.1 years, the disease-free survival (DFS) rates were significantly better in the RS 0-25 group (p = 0.02). Per the recurrent event type, there was no significant intergroup difference in locoregional recurrence (p = 0.139). However, a trend toward better distant DFS was observed in the RS 0-25 group (p = 0.08). Overall survival was also significantly better in this group (p = 0.027). Considering chemotherapy use, DFS worsened among chemotherapy-treated patients with an RS of 0-25 and those with an RS ≥ 26 who did not receive chemotherapy (p < 0.001). Seven (1.35%) chemotherapy-treated patients with an RS of 0-25 showed disease recurrence.

CONCLUSIONS

This study presents the largest database-derived prognostic data in Japanese patients, utilizing the Oncotype DX® treatment selection. Further studies are needed to determine the impact on treatment choice, considering the clinical risk, and the need for additional postoperative treatment.

Cyclin-Dependent Kinase 4/6 Inhibitors Plus Endocrine Therapy versus Endocrine Therapy Alone for HR-Positive, HER-2-Negative Early Breast Cancer: Meta-Analysis of Phase III Randomized Clinical Trials

BACKGROUND

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are approved for advanced breast cancer combined with endocrine therapy (ET). The efficacy of CDK4/6 inhibitors plus ET in hormone estrogen-positive, human epidermal growth factor 2-negative (HR+/HER2-) early-stage breast cancer (esBC) is still to be confirmed.

METHODS

We performed a systematic review and a meta-analysis to investigate the efficacy of CDK4/6i plus ET in esBC. Main outcomes included invasive disease-free survival (iDFS), distant relapse-free survival (DRFS), and overall survival (OS). We included only phase III randomized controlled trials. We used RStudio version 4.2.3, and we considered p < 0.05 to be statistically significant.

RESULTS

Four studies were selected, including 14,168 patients, of which 7089 were treated with CDK4/6i plus ET and 7079 received ET monotherapy. Regarding patient characteristics, 6828 (48.2%) were premenopausal. Compared with ET alone, iDFS rates (HR 0.81; 95% CI: 0.67, 0.98; p = 0.034) were significantly in favor of CDK4/6 inhibitors plus ET. However, there were no significant differences in DRFS (HR 0.79; 95% CI: 0.58, 1.07; p = 0.132) nor OS (HR 0.96; 95% CI: 0.69, 1.35; p = 0.829).

CONCLUSIONS

Our results show that the addition of CDK4/6 inhibitors is associated with a significant benefit for HR+/HER2- esBC patients in iDFS. More studies and longer follow-up are needed to assess overall survival benefits.

Impact of dose reductions on adjuvant abemaciclib efficacy for patients with high-risk early breast cancer: analyses from the monarchE study

In monarchE, adjuvant abemaciclib significantly improved invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS), with sustained benefit beyond the 2-year treatment period. Abemaciclib dose reductions were allowed to proactively manage adverse events. Exploratory analyses to investigate the impact of dose reductions on efficacy were conducted. Across the three patient subgroups as defined by relative dose intensity (≤66%, 66-93%, ≥93%), the estimated 4-year IDFS rates were generally consistent (87.1%, 86.4%, and 83.7%, respectively). In the time-dependent Cox proportional hazard model, the effect of abemaciclib was consistent at the full dose compared to being reduced to a lower dose (IDFS hazard ratio: 0.905; 95% confidence interval: 0.727, 1.125; DRFS hazard ratio: 0.942; 95% confidence interval: 0.742, 1.195). These analyses showed that the efficacy of adjuvant abemaciclib was not compromised by protocol mandated dose reductions for patients with node positive, hormone receptor positive, human epidermal growth factor 2-negative, high-risk early breast cancer.

Subspecialized breast pathologists have suboptimal interobserver agreement in Ki-67 evaluation using 20% as the cutoff

PURPOSE

Ki-67 expression levels in breast cancer have prognostic and predictive significance. Therefore, accurate Ki-67 evaluation is important for optimal patient care. Although an algorithm developed by the International Ki-67 in Breast Cancer Working Group (IKWG) improves interobserver variability, it is tedious and time-consuming. In this study, we simplify IKWG algorithm and evaluate its interobserver agreement among breast pathologists in Ki-67 evaluation.

METHODS

Six subspecialized breast pathologists (4 juniors, 2 seniors) assessed the percentage of positive cells in 5% increments in 57 immunostained Ki-67 slides. The time spent on each slide was recorded. Two rounds of ring study (R1, R2) were performed before and after training with the modified IKWG algorithm (eyeballing method at 400× instead of counting 100 tumor nuclei per area). Concordance was assessed using Kendall's and Kappa coefficients.

RESULTS

Analysis of ordinal scale ratings for all categories with 5% increments showed almost perfect agreement in R1 (0.821) and substantial in R2 (0.793); Seniors and juniors had substantial agreement in R1 (0.718 vs. 0.649) and R2 (0.756 vs. 0.658). In dichotomous scale analysis using 20% as the cutoff, the overall agreement was moderate in R1 (0.437) and R2 (0.479), among seniors (R1: 0.436; R2: 0.437) and juniors (R1: 0.445; R2: 0.505). Average scoring time per case was higher in R2 (71 vs. 37 s).

CONCLUSION

The modified IKWG algorithm does not significantly improve interobserver agreement. A better algorithm or assistance from digital image analysis is needed to improve interobserver variability in Ki-67 evaluation.

Assessing Knowledge, Competence, and Performance Following Web-Based Education on Early Breast Cancer Management: Health Care Professional Questionnaire Study and Anonymized Patient Records Analysis

BACKGROUND

Web-based learning activities are key components of continuing medical education (CME) for health care professionals (HCPs). However, the published outcomes of web-based educational interventions for early breast cancer (EBC) are limited.

OBJECTIVE

This study aims to objectively assess knowledge, competence, and performance among HCPs following participation in 2 EBC-focused CME activities and to identify the remaining educational gaps.

METHODS

We developed 2 CME-accredited web-based educational activities addressing high-risk EBC, including integration of shared decision-making to optimize patient care (touchMDT) and stratification for early identification of high-risk patients and novel treatment strategies (touchPANEL DISCUSSION). Knowledge, competence, and performance were assessed before and after the activities against an expanded outcomes framework (levels 1-5) using self-reported questionnaires and an analysis of anonymized data extracted from patient records.

RESULTS

Six months after the launch of the activity, 7047 and 8989 HCP participants engaged with touchMDT and touchPANEL DISCUSSION, respectively. The overall satisfaction was 82% (a total score of 20.6 out of 25) for the touchMDT and 88% (a total score of 21.9 out of 25) for the touchPANEL DISCUSSION. For the evaluation of knowledge and competence (50 respondents before the activity and 50 learners after the activity), there was a significant increase in the mean number of correctly answered questions from pre- to postactivity (touchMDT: median 4.0, IQR 3.0-5.0 to median 5.5, IQR 4.0-7.0; mean 4.00, SD 1.39 to mean 5.30, SD 1.56 and touchPANEL DISCUSSION: median 4.0, IQR 4.0-5.0 to median 6.0, IQR 5.0-7.0; mean 4.32, SD 1.30 to mean 5.88, SD 1.49; both P<.001). A significant improvement in self-reported performance (50 respondents before the activity and 50 learners after the activity) was observed in a combined analysis of both activities (median 3.0, IQR 2.0-3.0 to median 4.0, IQR 3.0-5.0; mean 2.82, SD 1.08 to mean 4.16, SD 1.45; P<.001). Patient record analysis (50 respondents before the activity and 50 learners after the activity) showed that the HCPs used a range of measures to determine EBC recurrence risk and revealed no significant differences in adjuvant therapies used before and after the activity (P=.97 and P>.99 for Ki-67 <20% and Ki-67 ≥20% tumors, respectively). The remaining educational gaps included strategies for implementing shared decision-making in clinical practice and the use of genetic and biomarker testing to guide treatment selection.

CONCLUSIONS

Brief, web-based CME activities on EBC were associated with an improvement in HCP knowledge, competence, and self-reported performance and can help identify unmet needs to inform the design of future CME activities.

Ribociclib plus Endocrine Therapy in Early Breast Cancer

BACKGROUND

Ribociclib has been shown to have a significant overall survival benefit in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer is unclear.

METHODS

In this international, open-label, randomized, phase 3 trial, we randomly assigned patients with HR-positive, HER2-negative early breast cancer in a 1:1 ratio to receive ribociclib (at a dose of 400 mg per day for 3 weeks, followed by 1 week off, for 3 years) plus a nonsteroidal aromatase inhibitor (NSAI; letrozole at a dose of 2.5 mg per day or anastrozole at a dose of 1 mg per day for ≥5 years) or an NSAI alone. Premenopausal women and men also received goserelin every 28 days. Eligible patients had anatomical stage II or III breast cancer. Here we report the results of a prespecified interim analysis of invasive disease-free survival, the primary end point; other efficacy and safety results are also reported. Invasive disease-free survival was evaluated with the use of the Kaplan-Meier method. The statistical comparison was made with the use of a stratified log-rank test, with a protocol-specified stopping boundary of a one-sided P-value threshold of 0.0128 for superior efficacy.

RESULTS

As of the data-cutoff date for this prespecified interim analysis (January 11, 2023), a total of 426 patients had had invasive disease, recurrence, or death. A significant invasive disease-free survival benefit was seen with ribociclib plus an NSAI as compared with an NSAI alone. At 3 years, invasive disease-free survival was 90.4% with ribociclib plus an NSAI and 87.1% with an NSAI alone (hazard ratio for invasive disease, recurrence, or death, 0.75; 95% confidence interval, 0.62 to 0.91; P = 0.003). Secondary end points - distant disease-free survival and recurrence-free survival - also favored ribociclib plus an NSAI. The 3-year regimen of ribociclib at a 400-mg starting dose plus an NSAI was not associated with any new safety signals.

CONCLUSIONS

Ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III early breast cancer. (Funded by Novartis; NATALEE ClinicalTrials.gov number, NCT03701334.).