Endocrine and Targeted Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer-Capivasertib-Fulvestrant: ASCO 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).

Optimizing Postneoadjuvant Treatment in Patients With Early Breast Cancer Achieving Pathologic Complete Response

pCR should be integrated with other prognostic factors to optimize postneoadjuvant treatments in BC.

Defining the Biology of Estrogen Receptor-Low-Positive Breast Cancer

BACKGROUND

We sought to better define estrogen receptor-low-positive (ER-low+) breast cancer biology and determine the utility of the Oncotype DX Breast Recurrence Score® (RS) assay in this population.

METHODS

Patients with information regarding percentage ER positivity and PAM50 subtype were identified in The Cancer Genome Atlas (TCGA) and subtype distribution was determined. Next, patients with ER-low+ (ER 1-10%), HER2- breast cancer undergoing upfront surgery with known RS result were identified in the National Cancer Database (NCDB) and our institutional Dana-Farber Brigham Cancer Center (DF/BCC) database; RS distribution was examined. Finally, patients with ER-low+, HER2- breast cancer treated at DF/BCC from 2011 to 2020 without prior RS results and in whom tissue was available to perform the assay were identified. RS results, treatment, recurrence and breast cancer-specific survival (BCSS) were determined.

RESULTS

Of 1033 patients in TCGA, ER percentage and PAM50 subtype were available for 342 (33.1%) patients. Forty-six (13.5%) had ER-low+/HER2- tumors, among whom 82.6% were basal and 4.3% were luminal A. Among 3423 patients with ER-low+/HER2- disease in the NCDB, RS results were available for 689 (20.1%) patients; 67% had an RS ≥26. In our institutional database, only two patients with ER-low+/HER2- disease and an RS were identified, both with RS ≥26. Among 37 patients in our institutional cohort without prior RS, 35 (97.4%) had an RS ≥26, determined with testing. After a median follow-up of 40 months (range 3-106), three patients, all treated with chemotherapy, recurred. Three-year BCSS was 97.0% (95% confidence interval 96.9-97.1%).

CONCLUSIONS

Most ER-low+/HER2- breast cancers are basal-like, with RS ≥26 suggesting these tumors are similar to triple-negative disease.

PACE: A Randomized Phase II Study of Fulvestrant, Palbociclib, and Avelumab After Progression on Cyclin-Dependent Kinase 4/6 Inhibitor and Aromatase Inhibitor for Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor-Negative Metastatic Breast Cancer

PURPOSE

Cyclin-dependent kinase (CDK) 4/6 inhibitors (CDK4/6is) are an important component of treatment for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC), but it is not known if patients might derive benefit from continuation of CDK4/6i with endocrine therapy beyond initial tumor progression or if the addition of checkpoint inhibitor therapy has value in this setting.

METHODS

The randomized multicenter phase II PACE trial enrolled patients with hormone receptor-positive/HER2- MBC whose disease had progressed on previous CDK4/6i and aromatase inhibitor (AI) therapy. Patients were randomly assigned 1:2:1 to receive fulvestrant (F), fulvestrant plus palbociclib (F + P), or fulvestrant plus palbociclib and avelumab (F + P + A). The primary end point was investigator-assessed progression-free survival (PFS) in patients treated with F versus F + P.

RESULTS

Overall, 220 patients were randomly assigned between September 2017 and February 2022. The median age was 57 years (range, 25-83 years). Most patients were postmenopausal (80.9%), and 40% were originally diagnosed with de novo MBC. Palbociclib was the most common previous CDK4/6i (90.9%). The median PFS was 4.8 months on F and 4.6 months on F + P (hazard ratio [HR], 1.11 [90% CI, 0.79 to 1.55]; P = .62). The median PFS on F + P + A was 8.1 months (HR v F, 0.75 [90% CI, 0.50 to 1.12]; P = .23). The difference in PFS with F + P and F + P + A versus F was greater among patients with baseline ESR1 and PIK3CA alterations.

CONCLUSION

The addition of palbociclib to fulvestrant did not improve PFS versus fulvestrant alone among patients with hormone receptor-positive/HER2- MBC whose disease had progressed on a previous CDK4/6i plus AI. The increased PFS seen with the addition of avelumab warrants further investigation in this patient population.

A randomized phase II study of metronomic cyclophosphamide and methotrexate (CM) with or without bevacizumab in patients with advanced breast cancer

PURPOSE

Metronomic chemotherapy has the potential to offer tumor control with reduced toxicity when compared to standard dose chemotherapy in patients with metastatic breast cancer. As metronomic chemotherapy may target the tumor microvasculature, it has the potential for synergistic effects with antiangiogenic agents such as the VEGF-A inhibitor bevacizumab.

METHODS

In this randomized phase II study, patients with metastatic breast cancer were randomized to receive metronomic oral cyclophosphamide and methotrexate (CM) combined with bevacizumab (Arm A) or CM alone (Arm B). The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety and tolerability.

RESULTS

A total of 55 patients were enrolled, with 34 patients treated on Arm A and 21 patients treated on Arm B. The ORR was modestly higher in Arm A (26%) than in Arm B (10%); neither met the 40% cutoff for further clinical evaluation. The median time to progression (TTP) was 5.52 months (3.22-13.6) on Arm A and 1.82 months (1.54-6.70) on Arm B (log-rank p = 0.008). The median OS was 29.6 months (17.2-NA) on Arm A and 16.2 months (15.7-NA) on Arm B (log-rank p = 0.7). Common all-grade adverse events in both arms included nausea, fatigue, and elevated AST.

CONCLUSION

The combination of metronomic CM with bevacizumab significantly improved PFS over CM alone, although there was no significant difference in OS. Oral metronomic chemotherapy alone has limited activity in advanced breast cancer.

CLINICALTRIALS

gov Identifier: NCT00083031. Date of Registration: May 17, 2004.

Understanding breast cancer complexity to improve patient outcomes: The St Gallen International Consensus Conference for the Primary Therapy of Individuals with Early Breast Cancer 2023

The 18th St Gallen International Breast Cancer Conference held in March 2023, in Vienna, Austria, assessed significant new findings for local and systemic therapies for early breast cancer with a focus on the evaluation of multimodal treatment options. The emergence of more effective, innovative agents in both the preoperative (primary or neoadjuvant) and post-operative (adjuvant) settings has underscored the pivotal role of a multidisciplinary approach in treatment decision making, particularly when selecting systemic therapy for an individual patient. The importance of multidisciplinary discussions regarding the clinical benefits of interventions was explicitly emphasized by the consensus panel as an integral part of developing an optimal treatment plan with the 'right' degree of intensity and duration. The panelists focused on controversies surrounding the management of common ductal/no special type and lobular breast cancer histology, which account for the vast majority of breast tumors. The expert opinion of the panelists was based on interpretations of available data, as well as current practices in their professional environments, personal and socioeconomic factors affecting patients, and cognizant of varying reimbursement and accessibility constraints around the world. The panelists strongly advocated patient participation in well-designed clinical studies whenever feasible. With these considerations in mind, the St Gallen Consensus Conference aims to offer guidance to clinicians regarding appropriate treatments for early-stage breast cancer and assist in balancing the realistic trade-offs between treatment benefit and toxicity, enabling patients and clinicians to make well-informed choices through a shared decision-making process.

Circulating tumor DNA association with residual cancer burden after neoadjuvant chemotherapy in triple-negative breast cancer in TBCRC 030

BACKGROUND

We aimed to examine circulating tumor DNA (ctDNA) and its association with residual cancer burden (RCB) using an ultrasensitive assay in patients with triple-negative breast cancer (TNBC) receiving neoadjuvant chemotherapy.

PATIENTS AND METHODS

We identified responders (RCB 0/1) and matched non-responders (RCB 2/3) from the phase II TBCRC 030 prospective study of neoadjuvant paclitaxel versus cisplatin in TNBC. We collected plasma samples at baseline, 3 weeks and 12 weeks (end of therapy). We created personalized ctDNA assays utilizing MAESTRO mutation enrichment sequencing. We explored associations between ctDNA and RCB status and disease recurrence.

RESULTS

Of 139 patients, 68 had complete samples and no additional neoadjuvant chemotherapy. Twenty-two were responders and 19 of those had sufficient tissue for whole-genome sequencing. We identified an additional 19 non-responders for a matched case-control analysis of 38 patients using a MAESTRO ctDNA assay tracking 319-1000 variants (median 1000 variants) to 114 plasma samples from 3 timepoints. Overall, ctDNA positivity was 100% at baseline, 79% at week 3 and 55% at week 12. Median tumor fraction (TFx) was 3.7 × 10-4 (range 7.9 × 10-7-4.9 × 10-1). TFx decreased 285-fold from baseline to week 3 in responders and 24-fold in non-responders. Week 12 ctDNA clearance correlated with RCB: clearance was observed in 10 of 11 patients with RCB 0, 3 of 8 with RCB 1, 4 of 15 with RCB 2 and 0 of 4 with RCB 3. Among six patients with known recurrence, five had persistent ctDNA at week 12.

CONCLUSIONS

Neoadjuvant chemotherapy for TNBC reduced ctDNA TFx by 285-fold in responders and 24-fold in non-responders. In 58% (22/38) of patients, ctDNA TFx dropped below the detection level of a commercially available test, emphasizing the need for sensitive tests. Additional studies will determine whether ctDNA-guided approaches can improve outcomes.

Clonal hematopoiesis in older patients with breast cancer receiving chemotherapy

BACKGROUND

The expansion of hematopoietic stem cells carrying recurrent somatic mutations, termed clonal hematopoiesis (CH), is common in elderly individuals and is associated with increased risk of myeloid malignancy and all-cause mortality. Though chemotherapy is a known risk factor for developing CH, how myelosuppressive therapies affect the short-term dynamics of CH remains incompletely understood. Most studies have been limited by retrospective design, heterogeneous patient populations, varied techniques to identifying CH, and analysis of single timepoints.

METHODS

We examined serial samples from 40 older women with triple-negative or hormone receptor-positive breast cancer treated on the prospective ADjuVANt Chemotherapy in the Elderly trial to evaluate the prevalence and dynamics of CH at baseline and throughout chemotherapy (6 and 12 weeks).

RESULTS

CH was detected in 44% of patients at baseline and in 53% at any timepoint. Baseline patient characteristics were not associated with CH. Over the course of treatment, mutations exhibited a variety of dynamics, including emergence, expansion, contraction, and disappearance. All mutations in TP53 (n = 3) and PPM1D (n = 4), genes that regulate the DNA damage response, either became detectable or expanded over the course of treatment. Neutropenia was more common in patients with CH, particularly when the mutations became detectable during treatment, and CH was significantly associated with cyclophosphamide dose reductions and holds (P = .02).

CONCLUSIONS

Our study shows that CH is common, dynamic, and of potential clinical significance in this population. Our results should stimulate larger efforts to understand the biological and clinical importance of CH in solid tumor malignancies.

TRIAL REGISTRATION

ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT03858322). Clinical trial registration number: NCT03858322.

ESMO expert consensus statements (ECS) on the definition, diagnosis, and management of HER2-low breast cancer

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged as a targetable subset of breast tumors, based on the evidence from clinical trials of novel anti-HER2 antibody-drug conjugates. This evolution has raised several biological and clinical questions, warranting the establishment of consensus to optimally treat patients with HER2-low breast tumors. Between 2022 and 2023, the European Society for Medical Oncology (ESMO) held a virtual consensus-building process focused on HER2-low breast cancer. The consensus included a multidisciplinary panel of 32 leading experts in the management of breast cancer from nine different countries. The aim of the consensus was to develop statements on topics that are not covered in detail in the current ESMO Clinical Practice Guideline. The main topics identified for discussion were (i) biology of HER2-low breast cancer; (ii) pathologic diagnosis of HER2-low breast cancer; (iii) clinical management of HER2-low metastatic breast cancer; and (iv) clinical trial design for HER2-low breast cancer. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. A review of the relevant scientific literature was conducted in advance. Consensus statements were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This article presents the developed statements, including findings from the expert panel discussions, expert opinion, and a summary of evidence supporting each statement.

Identifying Patterns and Barriers in OncotypeDX Recurrence Score Testing in Older Patients With Early-Stage, Estrogen Receptor-Positive Breast Cancer: Implications for Guidance and Reimbursement

PURPOSE

To evaluate the clinical patterns of utilization of OncotypeDX Recurrence Score (RS) in early-stage, hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer (BC) at an academic center with previously established internal reflex testing guidelines.

METHODS

RS testing in accordance with preexisting reflex criteria and predictors of utilization outside of reflex criteria were retrospectively analyzed for the years 2019-2021 in a quality improvement evaluation. Patients were grouped according to OncotypeDX testing within (cohort A) or outside (cohort B) of predefined criteria which included a cap at age older than 65 years.

RESULTS

Of 1,687 patients whose tumors had RS testing, 1,087 were in cohort A and 600 in cohort B. In cohort B, nearly half of patients were older than 65 years (n = 279; IQR, 67-72 years). For patients older than 65 years, those with RS testing were younger (median age: 69 v 73 years), with higher grade cancers (G2-3: 84.9% v 54.7%) and were more likely to be treated with chemotherapy (15.4% v 4.1%). Issues for implementation of RS testing in older patients were identified, including potential structural barriers related to the current policy on the reimbursements of genomic tests.

CONCLUSION

Internal guidelines may facilitate standardized utilization of the RS in early-BC. Our data suggest that clinicians preferred broader utilization of RS across the age spectrum, with therapeutically important consequences. Modifying the current policy for reimbursement of RS testing and in internal reflexive testing criteria for those older than 65 years is warranted.

NCCN Guidelines® Insights: Breast Cancer, Version 4.2023

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer address all aspects of management for breast cancer. The treatment landscape of metastatic breast cancer is evolving constantly. The therapeutic strategy takes into consideration tumor biology, biomarkers, and other clinical factors. Due to the growing number of treatment options, if one option fails, there is usually another line of therapy available, providing meaningful improvements in survival. This NCCN Guidelines Insights report focuses on recent updates specific to systemic therapy recommendations for patients with stage IV (M1) disease.

Testing for ESR1 Mutations to Guide Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: ASCO Guideline Rapid Recommendation Update

ASCO Rapid Recommendations 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. See the Appendix for disclaimers and other important information (Appendix 1 and Appendix 2, online only).

Circulating tumor DNA association with residual cancer burden after neoadjuvant chemotherapy in triple-negative breast cancer in TBCRC 030

Purpose

To examine circulating tumor DNA (ctDNA) and its association with residual cancer burden (RCB) using an ultrasensitive assay in patients with triple-negative breast cancer (TNBC) receiving neoadjuvant chemotherapy (NAT).

Patients and Methods

We identified responders (RCB-0/1) and matched non-responders (RCB-2/3) from the phase II TBCRC 030 prospective study of neoadjuvant paclitaxel vs. cisplatin in TNBC. We collected plasma samples at baseline, three weeks, and twelve weeks (end of therapy). We created personalized ctDNA assays utilizing MAESTRO mutation enrichment sequencing. We explored associations between ctDNA and RCB status and disease recurrence.

Results

Of 139 patients, 68 had complete samples and no additional NAT. Twenty-two were responders and 19 of those had sufficient tissue for whole-genome sequencing. We identified an additional 19 non-responders for a matched case-control analysis of 38 patients using a MAESTRO ctDNA assay tracking 319-1000 variants (median 1000) to 114 plasma samples from 3 timepoints. Overall, ctDNA positivity was 100% at baseline, 79% at week 3, and 55% at week 12. Median tumor fraction (TFx) was 3.7 × 10 -4 (range: 7.9 × 10 -7 to 4.9 × 10 -1 ). TFx decreased 285-fold from baseline to week 3 in responders and 24-fold in non-responders. Week 12 ctDNA clearance correlated with RCB: clearance was observed in 10/11 patients with RCB-0, 3/8 with RCB-1, 4/15 with RCB-2, and 0/4 with RCB-3. Among 6 patients with known recurrence five had persistent ctDNA at week 12.

Conclusion

NAT for TNBC reduced ctDNA TFx by 285-fold in responders and 24-fold in non-responders. In 58% (22/38) of patients, ctDNA TFx dropped below the detection level of a commercially available test, emphasizing the need for sensitive tests. Additional studies will determine if ctDNA-guided approaches can improve outcomes.

Adjuvant Endocrine Therapy in Premenopausal Breast Cancer: 12-Year Results From SOFT

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The Suppression of Ovarian Function Trial (SOFT; ClinicalTrials.gov identifier: NCT00066690) randomly assigned premenopausal women with hormone receptor-positive breast cancer to 5 years of adjuvant tamoxifen, tamoxifen plus ovarian function suppression (OFS), or exemestane plus OFS. The primary analysis compared disease-free survival (DFS) between tamoxifen plus OFS versus tamoxifen alone; exemestane plus OFS versus tamoxifen was a secondary objective. After 8 years, SOFT reported a significant reduction in recurrence and improved overall survival (OS) with adjuvant tamoxifen plus OFS versus tamoxifen alone. Here, we report outcomes after median follow-up of 12 years. DFS remained significantly improved with tamoxifen plus OFS versus tamoxifen (hazard ratio, 0.82; 95% CI, 0.69 to 0.98) with a 12-year DFS of 71.9% with tamoxifen, 76.1% with tamoxifen plus OFS, and 79.0% with exemestane plus OFS. OS was improved with tamoxifen plus OFS versus tamoxifen (hazard ratio, 0.78; 95% CI, 0.60 to 1.01) and was 86.8% with tamoxifen, 89.0% with tamoxifen plus OFS, and 89.4% with exemestane plus OFS at 12 years. Among those who received prior chemotherapy for human epidermal growth factor receptor-2-negative tumors, OS was 78.8% with tamoxifen, 81.1% with tamoxifen plus OFS, and 84.4% with exemestane plus OFS. In conclusion, after 12 years, there remains a benefit from including OFS in adjuvant endocrine therapy, with an absolute improvement in OS more apparent with higher baseline risk of recurrence.[Media: see text].

Adjuvant paclitaxel and trastuzumab for node-negative, HER2-positive breast cancer: final 10-year analysis of the open-label, single-arm, phase 2 APT trial

BACKGROUND

We aimed to report on long-term outcomes of patients with small, node-negative, HER2-positive breast cancer treated with adjuvant paclitaxel and trastuzumab and to establish potential biomarkers to predict prognosis.

METHODS

In this open-label, single-arm, phase 2 study, patients aged 18 years or older, with small (≤3 cm), node-negative, HER2-positive breast cancer, and an Eastern Cooperative Oncology Group performance status of 0-1, were recruited from 16 institutions in 13 cities in the USA. Eligible patients were given intravenous paclitaxel (80 mg/m²) with intravenous trastuzumab (loading dose of 4 mg/kg, subsequent doses 2 mg/kg) weekly for 12 weeks, followed by trastuzumab (weekly at 2 mg/kg or once every 3 weeks at 6 mg/kg) for 40 weeks to complete a full year of trastuzumab. The primary endpoint was 3-year invasive disease-free survival. Here, we report 10-year survival outcomes, assessed in all participants who received protocol-defined treatment, with exploratory analyses using the HER2DX genomic tool. This study is registered on ClinicalTrials.gov, NCT00542451, and is closed to accrual.

FINDINGS

Between Oct 29, 2007, and Sept 3, 2010, 410 patients were enrolled and 406 were given adjuvant paclitaxel and trastuzumab and included in the analysis. Mean age at enrolment was 55 years (SD 10·5), 405 (99·8%) of 406 patients were female and one (0·2%) was male, 350 (86·2%) were White, 28 (6·9%) were Black or African American, and 272 (67·0%) had hormone receptor-positive disease. After a median follow-up of 10·8 years (IQR 7·1-11·4), among 406 patients included in the analysis population, we observed 31 invasive disease-free survival events, of which six (19·4%) were locoregional ipsilateral recurrences, nine (29·0%) were new contralateral breast cancers, six (19·4%) were distant recurrences, and ten (32·3%) were all-cause deaths. 10-year invasive disease-free survival was 91·3% (95% CI 88·3-94·4), 10-year recurrence-free interval was 96·3% (95% CI 94·3-98·3), 10-year overall survival was 94·3% (95% CI 91·8-96·8), and 10-year breast cancer-specific survival was 98·8% (95% CI 97·6-100). HER2DX risk score as a continuous variable was significantly associated with invasive disease-free survival (hazard ratio [HR] per 10-unit increment 1·24 [95% CI 1·00-1·52]; p=0·047) and recurrence-free interval (1·45 [1·09-1·93]; p=0·011).

INTERPRETATION

Adjuvant paclitaxel and trastuzumab is a reasonable treatment standard for patients with small, node-negative, HER2-positive breast cancer. The HER2DX genomic tool might help to refine the prognosis for this population.

FUNDING

Genentech.

Adjuvant Exemestane With Ovarian Suppression in Premenopausal Breast Cancer: Long-Term Follow-Up of the Combined TEXT and SOFT Trials

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The combined analysis of SOFT-TEXT compared outcomes in 4,690 premenopausal women with estrogen/progesterone receptor-positive (ER/PgR+) early breast cancer randomly assigned to 5 years of exemestane + ovarian function suppression (OFS) versus tamoxifen + OFS. After a median follow-up of 9 years, exemestane + OFS significantly improved disease-free survival (DFS) and distant recurrence-free interval (DRFI), but not overall survival, compared with tamoxifen + OFS. We now report DFS, DRFI, and overall survival after a median follow-up of 13 years. In the intention-to-treat (ITT) population, the 12-year DFS (4.6% absolute improvement, hazard ratio [HR], 0.79; 95% CI, 0.70 to 0.90; P < .001) and DRFI (1.8% absolute improvement, HR, 0.83; 95% CI, 0.70 to 0.98; P = .03), but not overall survival (90.1% v 89.1%, HR, 0.93; 95% CI, 0.78 to 1.11), continued to be significantly improved for patients assigned exemestane + OFS over tamoxifen + OFS. Among patients with human epidermal growth factor receptor 2-negative tumors (86.0% of the ITT population), the absolute improvement in 12-year overall survival with exemestane + OFS was 2.0% (HR, 0.85; 95% CI, 0.70 to 1.04) and 3.3% in those who received chemotherapy (45.9% of the ITT population). Overall survival benefit was clinically significant in high-risk patients, eg, women age < 35 years (4.0%) and those with > 2 cm (4.5%) or grade 3 tumors (5.5%). These sustained reductions of the risk of recurrence with adjuvant exemestane + OFS, compared with tamoxifen + OFS, provide guidance for selecting patients for whom exemestane should be preferred over tamoxifen in the setting of OFS.[Media: see text].

'ADVANCE' (a pilot trial) ADjuVANt chemotherapy in the elderly: Developing and evaluating lower-toxicity chemotherapy options for older patients with breast cancer

INTRODUCTION

Older adults with breast cancer receiving neo/adjuvant chemotherapy are at high risk for poor outcomes and are underrepresented in clinical trials. The ADVANCE (ADjuVANt Chemotherapy in the Elderly) trial evaluated the feasibility of two neo/adjuvant chemotherapy regimens in parallel-enrolling cohorts of older patients with human epidermal growth factor receptor 2-negative breast cancer: cohort 1-triple-negative; cohort 2-hormone receptor-positive.

MATERIALS AND METHODS

Adults age ≥ 70 years with stage I-III breast cancer warranting neo/adjuvant chemotherapy were enrolled. Cohort 1 received weekly carboplatin (area under the curve 2) and weekly paclitaxel 80 mg/m2 for twelve weeks; cohort 2 received weekly paclitaxel 80 mg/m2 plus every-three-weekly cyclophosphamide 600 mg/m2 over twelve weeks. The primary study endpoint was feasibility, defined as ≥80% of patients receiving ≥80% of intended weeks/doses of therapy. All dose modifications were applied per clinician discretion.

RESULTS

Forty women (n = 20 per cohort) were enrolled from March 25, 2019 through August 3, 2020 from three centers; 45% and 35% of patients in cohorts 1 and 2 were age > 75, respectively. Neither cohort achieved targeted thresholds for feasibility. In cohort 1, eight (40.0%) met feasibility (95% confidence interval [CI] = 19.1-63.9%), while ten (50.0%) met feasibility in cohort 2 (95% CI = 27.2-72.8). Neutropenia was the most common grade 3-4 toxicity (cohort 1-65%, cohort 2-55%). In cohort 1, 80% and 85% required ≥1 dose holds of carboplatin and/or paclitaxel, respectively. In cohort 2, 10% required dose hold(s) for cyclophosphamide and/or 65% for paclitaxel.

DISCUSSION

In this pragmatic pilot examining chemotherapy regimens in older adults with breast cancer, neither regimen met target goals for feasibility. Developing efficacious and tolerable regimens for older patients with breast cancer who need chemotherapy remains an important goal.

CLINICALTRIALS

gov Identifier: NCT03858322.

Postneoadjuvant treatment for triple-negative breast cancer

PURPOSE OF REVIEW

Triple-negative breast cancer (TNBC) has been conventionally associated with poor prognosis, as a result of limited therapeutic options. In the early setting, prognosis is informed by clinical-pathological factors; for patients receiving neoadjuvant treatments, pathological complete response (pCR) is the strongest factor. In this review, we mapped the landscape of clinical trials in the postneoadjuvant space, and identified three patterns of clinical trial design.

RECENT FINDINGS

For patients at higher risk, effective postneoadjuvant treatments are of paramount importance to address a high clinical need. Postneoadjuvant risk-adapted treatments have demonstrated to improve survival in patients at high of recurrence.

SUMMARY

Patients at high risk have indication for adjuvant treatment intensification, informed by baseline clinical, pathological or molecular factors (type 1 approach), on the presence, extent and molecular characteristics of the residual disease at the time of surgery (type 2) or on risk factors assessed in the postsurgical setting (type 3), for example, circulating tumour DNA. Most of the past trials were based on type 2 approaches, for example, with capecitabine and Olaparib. Few trials were based on a type 1 approach, notably pembrolizumab for early TNBC. The clinical validity of type 3 approaches is under investigation in several ongoing trials.

Adjuvant palbociclib for ER+ breast cancer (PALLAS Trial (ABCSG-42/AFT-05/PrE0109/BIG-14-13): A preplanned analysis of the stage IIA cohort

390216

Background: CDK4/6 inhibitors have become standard of care for advanced hormone receptor positive, HER2-negative (HR+/HER2-) breast cancer in combination with endocrine therapy (ET), with one approved for high-risk patients (pts) in the adjuvant setting. The PALLAS Trial investigated the addition of palbociclib to adjuvant ET in pts with stage II-III breast cancer. Stage IIA patients were specifically enrolled to evaluate the potential benefit of using palbociclib with adjuvant ET pts diagnosed at lower risk who may have more indolent disease. Methods: In the prospective, randomized, phase III PALLAS trial, pts with HR+/HER2- early breast cancer were randomly assigned to receive adjuvant ET for at least 5 years with or without 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle). ET was of provider’s choice. Stage IIA enrollment was capped at 1,000 patients. While the primary end point of the overall study was invasive disease-free survival (iDFS) for the entire cohort, there was a preplanned analysis of recurrence and survival endpoints in the stage IIA cohort. Outcomes were compared between arms using stratified log-rank tests and Cox models (stratification factors: chemotherapy and age ≤ 50). Results: Among 5,796 pts enrolled at 406 centers in 21 countries worldwide between 9/1/2015 and 11/30/2018, a total of 1,010 stage IIA pts were enrolled. The protocol-defined number of events occurred at a median follow-up of 50 months for this subgroup (43.1 months for the overall study). Median age within this subgroup was 54 (range 29-85 yrs), and 410 (40.6%) were pre/perimenopausal, 506 (50.1%) T2/N0 (vs T0-1/N1), 272 (26.9%) grade 3 (vs. grade1/2), and 561 (55.5%) received chemotherapy. iDFS events occurred in 31 of 503 (6.2%) pts who received palbociclib plus ET and in 45 of 507 (8.9%) pts who received ET alone, resulting in a statistically nonsignificant difference in iDFS at 4 years (92.9% vs. 92.1%; hazard ratio, 0.75; CI, 0.48 to 1.19; P = .23). Nonsignificant differences were also observed for invasive breast cancer-free, distant recurrence-free, and locoregional cancer-free survival. No significant differences in iDFS were observed in subgroups including age group, receipt of chemotherapy, tumor grade, and clinical risk (T1/N1 vs. T2/N0).Conclusions: In this preplanned analysis of the stage IIA cohort of the PALLAS trial, the addition of adjuvant palbociclib to standard ET did not improve outcomes over ET alone, suggesting no benefit from the agent in reducing the incidence of early relapse in pts with lower-stage HR+/HER2- breast cancer. Future analyses will incorporate genomic risk and other molecular patterns from the extensive transPALLAS correlative program. Additional follow-up (10-year minimum) is also underway to assess the impact of palbociclib exposure on late recurrence in HR+ disease. Clinical trial information: NCT02513394.

Expanding the Staging Criteria for T1-2N0 Hormone-Receptor Positive Breast Cancer Patients Enrolled in TAILORx

BACKGROUND

The American Joint Committee on Cancer (AJCC) 8th edition pathologic prognostic staging (PPS) incorporates anatomic and biologic factors. The OncotypeDX Breast Recurrence Score (RS) was included based on the initial report of the TAILORx trial, with T1-2N0 hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer patients who had a RS < 11 staged as PPS 1A. This study examined whether the RS criteria for PPS 1A can be further expanded using patients enrolled in the TAILORx trial.

METHODS

The TAILORx trial enrolled 10,273 HR+HER2- T1-2N0 patients. Those with incomplete HR-status/grade and T3 disease were excluded for analysis. The recurrence-free interval (RFI) was compared between the patients who did and those who did not fall into the current PPS 1A category using the Kaplan-Meier method.

RESULTS

The study enrolled 9535 patients for analysis. The RS was < 11 in 16.1%, 11-17 in 35.9%, 18-25 in 32.4%, and > 25 in 15.6% of the patients. The majority (91.2%) of the patients (including all the T1N0 patients regardless of RS) were PPS 1A, and 8.8% were not-PPS 1A. The median follow-up time was 95 months. The PPS 1A patients had an 8-year RFI of 94.2%, which was similar to that of the patients with a RS of 11-17 who were not-PPS 1A (91.7%; p = 0.07) and better than that of the patients with a RS ≥ 18 who were not-PPS 1A (85.4% for a RS of 18-25, 76.0% for a RS > 25; both p < 0.01). Similar RFI trends were seen in patients who received endocrine therapy or chemotherapy followed by endocrine therapy.

CONCLUSIONS

Patients with T1-2N0 HR+HER2- breast cancer and a RS < 18 have an RFI similar to that of patients staged as PPS 1A by the current AJCC staging system, regardless of treatment, suggesting that the criteria for PPS 1A can be expanded to include a RS < 18.

Sentinel Lymph Node Biopsy Alone is Adequate for Chemotherapy Decisions in Postmenopausal Early-Stage Hormone-Receptor-Positive, HER2-Negative Breast Cancer with One to Three Positive Sentinel Lymph Nodes

BACKGROUND

The RxPONDER trial randomized patients with cT1-3N0 hormone receptor-positive, HER2-negative (HR⁺HER2^-) breast cancer and one to three positive nodes and Recurrence Score (RS) < 26 to endocrine therapy (ET) or chemoendocrine therapy (CET) with equivalent survival in postmenopausal women. In current practice, cN0 patients with one or two positive sentinel lymph nodes (SLN) do not undergo axillary lymph node dissection (ALND), raising concerns about applying these data in patients who may have additional nodal disease.

METHODS

We identified institutional [Dana-Farber Brigham Cancer Center (DF/BCC), 2016-2020] and national [National Cancer Database (NCDB), 2012-2017] cohorts of women aged 50-75 years with cT1-3N0 HR⁺HER2^- breast cancer and RS < 26 treated with upfront surgery with one to three positive SLN. Axillary nodal burden and outcomes were assessed on the basis of the number of positive nodes and CET use.

RESULTS

A total of 197 and 13,499 HR⁺HER2^- eligible patients with one to three positive SLN and RS < 26 were identified in the DF/BCC and NCDB databases, respectively, and 12.7% of DF/BCC and 32.4% of NCDB patients had ALND. Of these, only 12.0 and 4.9% had more than three total positive nodes, respectively. Rates of CET were 6.6% in DF/BCC and 20.9% in NCDB patients. In the NCDB, similar adjusted 4-year overall survival was seen between patients treated with CET or ET for any number of positive nodes (98.1-99.9%, all p > 0.05).

CONCLUSIONS

Postmenopausal women with cT1-3N0 HR⁺HER2^- breast cancer and RS < 26 with one to three positive SLN are unlikely to have more than three total positive nodes. CET decisions should continue to be based on SLN biopsy as ALND is unlikely to change treatment recommendations or outcomes.

Breast Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. These NCCN Clinical Practice Guidelines for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of ductal carcinoma in situ and the workup and locoregional management of early stage invasive breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org.

Is there a role for the oncotype DX breast recurrence score genomic assay in estrogen receptor-low positive breast cancer?

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Background: The Oncotype DX Breast Recurrence Score assay is widely used in estrogen receptor (ER)-positive breast cancer patients to help determine the potential benefit of chemotherapy. However, little is known about the value of the test in breast cancer patients who have ER-low positive (1-10%) cancers. The purpose of this study was to determine the potential utility of the Oncotype test for these patients by describing the range of Recurrence Score (RS) results and patient outcomes. Methods: Patients treated between 8/2011-8/2020 for primary non-metastatic breast cancer that was ER-low positive (10%) and HER2-negative in whom tissue from their surgical excision specimen was available to perform the Oncotype DX assay were identified. Clinicopathologic characteristics were abstracted from patient charts, and the RS result was determined. Results: 38 women with ER-low positive breast cancer and available tissue were identified. The median age was 56.5 (range 36-94); 34 patients were Caucasian, 2 Black, 1 Asian and 1 Hispanic. Thirty-seven patients underwent surgery as their initial intervention and 1 received neoadjuvant chemotherapy. The final pathologic anatomic stage was IA in 26 (68.4%), IB in 10 (26.3%) and IIA in 2 (5.3%); the pathologic nodal status was pN0 in 24 (63.2%), pN0i+ in 3 (7.9%), pN1mi in 1 (2.6%), pN1 in 6 (15.8%) and pNx in 4 (10.5%). The average and median RS was 49 with a range of 23-72; only 2 patients had a RS 25. One patient with RS = 24 was a 64yo with pT1cN0 disease who received chemotherapy + endocrine therapy therefore could potentially have been spared chemotherapy based on the RS result and the TAILORx trial data. Six patients had previously had a RS determined on their diagnostic core biopsy (RS = 46, 58, 45, 47, 51 and 52); the RS on their surgical specimen was concordant (RS = 45, 54, 47, 48, 47, and 50). The ER status as determined by the Oncotype DX assay was positive for 8 (21%) patients. Adjuvant therapy included: chemotherapy and endocrine therapy in 13 (34.2%), chemotherapy alone in 13 (34.2%) and endocrine therapy alone in 4 (10.5%). 8 (21.1%) received no adjuvant therapy. After a median follow-up of 40 months (range 3-106), 3 patients have experienced a recurrence; all 3 had received chemotherapy. The 3-year recurrence free survival rate was 97.0% (95% CI: 96.9-97.1%). All 3 of these patients had a local recurrence; 2 also had a distant recurrence which they ultimately succumbed to. The 3-year disease-specific survival rate was also 97.0% (95% CI: 96.9-97.1%). Conclusions: The majority of the patients with low ER+/HER2- breast cancer had RS > 25 suggesting these tumors are high-risk, more similar to ER- disease. The RS result is of limited utility in ER-low positive patients, as these data indicate that most would benefit from chemotherapy.

A look at current and potential treatment approaches for hormone receptor-positive, HER2-negative early breast cancer

The heterogeneity of hormone receptor (HR)-positive, HER2-negative early breast cancers reinforces the importance of individualized, risk-adapted treatment approaches. Numerous factors contribute to the risk for recurrence, including clinical tumor features, individual biomarkers, and genomic risk. Current standard approaches for patients with HR-positive, HER2-negative, early stage disease focus on endocrine therapy and chemotherapy. The specific treatment regimen and duration of adjuvant therapy should be selected based on accurate risk assessment, tolerability of available therapies, and consideration for patient preferences. For patients with high-risk features, such as highly proliferative tumors, large tumor size, and significant nodal involvement, the risk for recurrence remains clinically significant despite appropriate adjuvant treatment with current standards of care. This has driven investigation into novel treatment approaches, including the addition of cyclin-dependent kinase 4 and 6 inhibitors to adjuvant endocrine therapy. Cyclin-dependent kinase 4 and 6 inhibition has demonstrated significant efficacy in patients with high-risk, HR-positive, HER2-negative, nonmetastatic breast cancer and now offers a new strategy to greatly improve outcomes in this difficult to treat patient population.; LAY SUMMARY: Hormone receptor (HR)-positive, HER2-negative early breast cancers are highly diverse and need to be managed differently for individual patients. The use of adjuvant endocrine therapy and chemotherapy should be driven by a patient's risk for recurrence, preferences, and risk for side effects. Patients with high-risk tumors have a persistently elevated risk for recurrence despite current standards of care. Emerging cyclin-dependent kinase 4 and 6 inhibitors are highly effective when added to endocrine therapy in high-risk, HR-positive early breast cancer and have the potential to improve patient outcomes in this difficult to treat patient population.

Risk-adapted modulation through de-intensification of cancer treatments: an ESMO classification

BACKGROUND

The landscape of clinical trials testing risk-adapted modulations of cancer treatments is complex. Multiple trial designs, endpoints, and thresholds for non-inferiority have been used; however, no consensus or convention has ever been agreed to categorise biomarkers useful to inform the treatment intensity modulation of cancer treatments.

METHODS

An expert subgroup under the European Society for Medical Oncology (ESMO) Precision Medicine Working Group shaped an international collaborative project to develop a classification system for biomarkers used in the cancer treatment de-intensification, based on a tiered approach. A group of disease-oriented clinical, translational, methodology and public health experts, and patients' representatives provided an analysis of the status quo, and scanned the horizon of ongoing clinical trials. The classification was developed through multiple rounds of expert revisions and inputs.

RESULTS

The working group agreed on a univocal definition of treatment de-intensification. Evidence of reduction in the dose-density, intensity, or cumulative dose, including intermittent schedules or shorter treatment duration or deletion of segment(s) of the standard regimens, compound(s), or treatment modality must be demonstrated, to define a treatment de-intensification. De-intensified regimens must also portend a positive impact on toxicity, quality of life, health system burden, or financial toxicity. ESMO classification categorises the biomarkers for treatment modulation in three tiers, based on the level of evidence. Tier A includes biomarkers validated in prospective, randomised, non-inferiority clinical trials. The working group agreed that in non-inferiority clinical trials, boundaries are highly dependent upon the disease scenario and endpoint being studied and that the absolute differences in the outcomes are the most relevant measures, rather than relative differences. Biomarkers tested in single-arm studies with a threshold of non-inferiority are classified as Tier B. Tier C is when the validation occurs in prospective-retrospective quality cohort investigations.

CONCLUSIONS

ESMO classification for the risk-guided intensity modulation of cancer treatments provides a set of evidence-based criteria to categorise biomarkers deemed to inform de-intensification of cancer treatments, in risk-defined patients. The classification aims at harmonising definitions on this matter, therefore offering a common language for all the relevant stakeholders, including clinicians, patients, decision-makers, and for clinical trials.

Local Therapy Outcomes and Toxicity From the ATEMPT Trial (TBCRC 033): A Phase II Randomized Trial of Adjuvant Trastuzumab Emtansine Versus Paclitaxel in Combination With Trastuzumab in Women With Stage I HER2-Positive Breast Cancer

PURPOSE

Human epidermal growth factor receptor 2 (HER2)-directed therapy improves local control among women with HER2-positive breast cancer. This retrospective analysis evaluates the safety and efficacy of radiation therapy (RT) among patients receiving adjuvant trastuzumab emtansine (T-DM1) or paclitaxel (T) plus trastuzumab (H) in the ATEMPT (Adjuvant Trastuzumab Emtansine Versus Paclitaxel in Combination With Trastuzumab) trial; Translational Breast Cancer Research Consortium (TBCRC) 033.

METHODS AND MATERIALS

Patients with stage I HER2-positive breast cancer were randomized 3:1 to receive adjuvant T-DM1 or TH after mastectomy or breast-conserving surgery (BCS). Breast RT was required after BCS and permitted after mastectomy. Patients receiving T-DM1 began RT after 12 weeks of therapy and received RT concurrently with T-DM1. Patients receiving TH began RT after paclitaxel, but concurrent with trastuzumab. RT records were retrospectively reviewed to determine details of radiation delivery and acute RT-related toxicity.

RESULTS

Protocol therapy was initiated by 497 patients. Among the 299 BCS patients, 289 received whole breast RT (WBRT) and 10 partial breast. Among WBRT patients, 40.2% in the T-DM1 arm and 41.5% of TH patients received hypofractionated (≥2.5 Gy/fraction) RT. Eight mastectomy patients received RT, all conventional fractionation. Skin toxicity (grade ≥2) was seen in 33.9% of patients in the T-DM1 arm and 23.2% in the TH arm (P = .11). In conventionally fractionated WBRT patients, 44.7% had a grade ≥2 skin toxicity compared with 17.9% of patients receiving hypofractionation (P < .001). Five patients experienced pneumonitis after RT (T-DM1: n = 4, 1.0%; TH: n = 1, 0.9%). Three-year invasive disease-free survival was 97.8% for T-DM1 (95% confidence interval, 96.3-99.3) and 93.4% for TH (95% confidence interval, 88.7-98.2). Among the 18 invasive disease-free survival events, 7 were isolated locoregional recurrences (2, T-DM1; 5, TH).

CONCLUSIONS

RT was well-tolerated when given concurrently with either T-DM1 or TH. Among BCS patients, hypofractionation resulted in lower grade ≥2 acute skin toxicity even with concurrent anti-HER2 therapy. Although follow-up was short, local recurrences were uncommon, attesting to the efficacy of HER2-directed therapy combined with RT.

Unmet challenges in systemic therapy for early stage breast cancer

Despite marked progress in outcomes for women with early stage breast cancer, unmet challenges persist. These include accounting for the cohort of tumors that do not have favorable clinical outcomes related to tumor heterogeneity, particularly the variation within the subset of ER positive breast cancer; better treatments for subsets where existing therapies are not fully effective; and the development of biomarkers to predict response or need for ongoing treatment. Beyond these tumor-related factors, there is persistent need for focus on improving the patient's experience of treatment - avoiding unnecessary therapy, and providing better supportive care so as to minimize side effects and social and economic disruption caused by treatment. For clinical investigators, the improved prognosis for early stage breast cancer has meant that large sample sizes of subjects are needed for prospective clinical trials with cancer outcome endpoints. As a consequence, the scale of clinical research enterprises has become enormous, too often unsupportable without industry or government resources. Finally, as breast cancer is a global health concern, there is an urgent need to assure that screening and treatment are available to women around the world so that the progress achieved in developed countries can reach billions of women everywhere on earth.

Abstract GS2-05: Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): update of the combined TEXT and SOFT trials

Background The updated combined SOFT+TEXT analysis, after 9 years median follow-up (MFU), revealed that adjuvant E+OFS vs T+OFS significantly improved disease-free survival (DFS) and distant recurrence-free interval (DRFI) but not overall survival (OS) in premenopausal women with HR+ early BC (Francis et al NEJM 2018). Given the high rate of OS in both arms and the long-term risk of relapse in HR+ BC, continued follow-up is key to assessing treatment benefit. We report a planned update analysis including OS with database lock of May 2021, after 13 years MFU.. Methods TEXT and SOFT enrolled premenopausal women with HR+ early BC from November 2003 to April 2011 (2660 in TEXT, 3047 in SOFT intention-to-treat (ITT) populations). TEXT randomized women within 12 weeks of surgery to 5 years E+OFS vs T+OFS; chemotherapy (CT) was optional and concurrent with OFS. SOFT randomized women to 5 years E+OFS vs T+OFS vs T alone, within 12 weeks of surgery if no CT planned, or within 8 months of completing (neo)adjuvant CT. Both trials were stratified by CT use. For the combined analysis of E+OFS vs T+OFS, the primary endpoint was DFS defined as invasive local, regional, distant recurrence, contralateral BC, second malignancy, death. Secondary endpoints included invasive breast cancer-free interval (BCFI), DRFI and OS.. Results: At database lock there were 953 DFS events and 473 deaths among 4690 pts assigned to T+OFS or E+OFS. In the ITT population, DFS, BCFI and DRFI outcomes for pts assigned E+OFS (n=2346) continued to be significantly improved over T+OFS (n=2344). 12-yr DFS was 80.5% vs. 75.9% (4.6% absolute improvement; HR 0.79 95% CI 0.70-0.90), 12-yr BCFI was improved by 4.1% and 12-yr DRFI by 1.8%. At 12 years OS was excellent in both groups, 90.1% in pts assigned E+OFS vs 89.1% in pts assigned T+OFS (HR 0.93; 95% CI, 0.78-1.11). There was heterogeneity of relative treatment effect according to HER2 status. When enrollment commenced, anti-HER2 adjuvant therapy was not standard; 53% of 583 pts with HER2+ tumors received HER2-targeted therapy. Below are Kaplan-Meier 12-yr estimates for patients with HER2 negative tumors by trial and chemotherapy stratum and for those with high-grade tumours, as an example of high-risk feature (Table). There is an emerging OS benefit for E+OFS vs T+OFS in pts with HER2 negative tumors who received chemotherapy in both trials.In pts with HER2-negative tumors, clinically-relevant outcome benefits were also seen in other high-risk subgroups: 12-yr DFS and OS were improved by 7.4% and 2.7%, respectively, in pts with pN1a disease, and by 10.6% and 4.5%, respectively, in those with tumors &gt;2cm.

Conclusions After 13 years MFU, adjuvant E+OFS, as compared with T+OFS, shows a sustained reduction in the risk of recurrence, more consistent in HER2 negative patients and in those with high-risk disease features, e.g., indication for adjuvant chemotherapy and G3 tumors. Oncologists may use this information to discuss potential benefits of E+OFS with individual patients. Follow-up continues for 5 additional years.

Chemotherapy HER2-negativeSOFTT+OFS (n=424)E+OFS (n=411)Absolute difference12-yr DFS67.4%74.1%6.7%12-yr OS81.1%84.4%3.3%TEXTT+OFS (n=656)E+OFS (n=661)Absolute difference12-yr DFS71.0%78.4%7.4%12-yr OS83.5%86.8%3.3%No chemotherapy HER2-negativeSOFTT+OFS (n=445)E+OFS (n=447)Absolute difference12-yr DFS82.9%88.2%5.3%12-yr OS96.1%96.9%0.9%TEXTT+OFS (n=499)E+OFS (n=492)Absolute difference12-yr DFS80.2%86.7%6.5%12-yr OS95.9%96.2%0.2%G3 HER2-negativeT+OFS (n=423)E+OFS (n=405)Absolute difference12-yr DFS62.7%73.0%10.3%12-yr OS78.1%83.6%5.5%

Citation Format: Meredith M Regan, Barbara A Walley, Gini F Fleming, Prudence A Francis, Marco A Colleoni, István Láng, Henry L Gómez, Carlo A Tondini, Harold J Burstein, Matthew P Goetz, Eva M Ciruelos, Vered Stearns, Hervé R Bonnefoi, Silvana Martino, Charles E Geyer, Jr, Claudio Chini, Alessandro M Minisini, Simon Spazzapan, Thomas Ruhstaller, Eric P Winer, Barbara Ruepp, Sherene Loi, Alan S Coates, Aron Goldhirsch, Richard D Gelber, Olivia Pagani. Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): update of the combined TEXT and SOFT trials [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS2-05.

Abstract PD9-01: Expanding downstaging criteria in AJCC pathologic prognostic staging using OncotypeDx Recurrence Score® assay in T1-2N0 hormone-receptor positive patients enrolled in the TAILORx trial

Background: The AJCC 8th edition pathologic prognostic staging (PPS) system, which incorporates both anatomic and biologic factors, was developed using data from patients captured in the National Cancer Database diagnosed 2010-2012 in whom complete anatomic (T, N and M category) as well as biologic data (grade, ER, PR, HER2) were available. The clinical endpoint was 3-year overall survival. In addition, the use of genomic assays was incorporated based on the initial report from the TAILORx trial, with patients with T1-2N0 hormone-receptor positive, HER2 negative (HR+,HER2-) breast cancer and an Oncotype DX Recurrence Score® (RS) result &lt;11 being staged as PPS IA. Given availability of long-term prospective followup data from TAILORx, we undertook this study to examine if the RS criteria for downstaging to PPS IA can be expanded using the patients enrolled on this trial. Methods: TAILORx assigned T1-2N0 HR+HER2- breast cancer patients with RS &lt;11 to endocrine therapy (ET) alone and RS &gt;25 to chemotherapy followed by ET (CET). Those with RS 11-25 were randomized to ET or CET. 10,273 patients were enrolled. Patients with incomplete HR status or grade and those with T3 disease were excluded for this analysis. Recurrence-free survival (RFS) in patients with RS &lt;11 were compared between patients that did and did not fall into current AJCC PPS IA category using the Kaplan-Meier method. Results: 9,535 patients were included for analysis. The majority were &gt; 50 years old (n=6893, 72.3%), had T1 tumors (n=6561, 68.8%), grade 2 disease (n=5291, 55.5%), and underwent lumpectomy (n=6855, 71.9%). RS breakdown was &lt;11 in 1539 (16.1%), 11-17 in 3423 (35.9%), 18-25 in 3088 (32.4%) and &gt;25 in 1485 (15.6%). 8,698 (91.2%) patients were AJCC PPS IA (including all T1N0 patients regardless of RS), and 837 (8.8%) were not PPS IA. Median follow-up time was 95 months. PPS IA patients had 8-yr RFS of 94.2% which was statistically similar to patients with RS 11-17 that were not PPS IA (91.7%, p=0.07) and better than patients with RS &gt;18 that were not PPS IA (85.4% for RS 18-25, 76.0% for RS &gt;25, p&lt;0.01). For patients with a RS 11-17 that were not PPS IA receiving ET alone, 8-yr RFS was 93.3% which was statistically similar to PPS IA patients receiving ET alone (94.9%, p=0.24). There was no RFS benefit with CET for patients with RS 11-17 not PPS IA (Table). Conclusions: Patients with T1-2N0 HR+HER2- breast cancer and RS&lt;18 have similar RFS to patients staged as PPS IA by the current AJCC staging system, regardless of treatment, suggesting that consideration could be given to expanding the criteria for pathologic prognostic stage IA to include RS&lt;18.

Comparison of RFS in patients with Stage IA and not Stage IA by AJCC PPS, n=9535Stage IANot stage IA, RS 11-17Not stage IA, RS 18-25Not stage IA, RS &gt;25All Patients, n=9535n=8698n=169n=269n=3998yr RFS % (95% CI)94.2 (93.6-94.8)91.7 (87.0-96.4)85.4 (80.3-90.5)76.0 (69.1-82.9)P-value*Ref0.07&lt;0.01&lt;0.01ET, n=5370n=5123n=88n=135n=248yr RFS % (95% CI)94.9 (94.1-95.7)93.3 (87.6-99.9)85.1 (77.8-92.4)58.3 (77.8-92.4)P-value*Ref0.24&lt;0.01&lt;0.01CET, n=4165n=3575n=81n=134n=3758yr RFS % (95% CI)93.2 (92.2-94.2)90.0 (82.4-97.6)85.8 (78.7-92.9)76.9 (69.8-84.0)P-value*Ref0.019&lt;0.01&lt;0.01ET endocrine therapy; CET chemoendocrine therapy*compared to T1-2N0 patients with PPS IA

Citation Format: Olga Kantor, Harold J Burstein, Tari King, Steven Shak, Christy Russell, Armando E Giuliano, Gabriel N Hortobagyi, Eric P Winer, Larissa A Korde, Joseph A Sparano, Elizabeth A Mittendorf. Expanding downstaging criteria in AJCC pathologic prognostic staging using OncotypeDx Recurrence Score® assay in T1-2N0 hormone-receptor positive patients enrolled in the TAILORx trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD9-01.

Treatment Exposure and Discontinuation in the PALbociclib CoLlaborative Adjuvant Study of Palbociclib With Adjuvant Endocrine Therapy for Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast Cancer (PALLAS/AFT-05/ABCSG-42/BIG-14-03)

PURPOSE

The PALLAS study investigated whether the addition of palbociclib, an oral CDK4/6 inhibitor, to adjuvant endocrine therapy (ET) improves invasive disease-free survival (iDFS) in early hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer. In this analysis, we evaluated palbociclib exposure and discontinuation in PALLAS.

METHODS

Patients with stage II-III HR+, HER2- disease were randomly assigned to 2 years of palbociclib with adjuvant ET versus ET alone. The primary objective was to compare iDFS between arms. Continuous monitoring of toxicity, dose modifications, and early discontinuation was performed. Association of baseline covariates with time to palbociclib reduction and discontinuation was analyzed with multivariable competing risk models. Landmark and inverse probability weighted per-protocol analyses were performed to assess the impact of drug persistence and exposure on iDFS.

RESULTS

Of the 5,743 patient analysis population (2,840 initiating palbociclib), 1,199 (42.2%) stopped palbociclib before 2 years, the majority (772, 27.2%) for adverse effects, most commonly neutropenia and fatigue. Discontinuation of ET did not differ between arms. Discontinuations for non-protocol-defined reasons were greater in the first 3 months of palbociclib, and in the first calendar year of accrual, and declined over time. No significant relationship was seen between longer palbociclib duration or ≥ 70% exposure intensity and improved iDFS. In the weighted per-protocol analysis, no improvement in iDFS was observed in patients receiving palbociclib versus not (hazard ratio 0.89; 95% CI, 0.72 to 1.11).

CONCLUSION

Despite observed rates of discontinuation in PALLAS, analyses suggest that the lack of significant iDFS difference between arms was not directly related to inadequate palbociclib exposure. However, the discontinuation rate illustrates the challenge of introducing novel adjuvant treatments, and the need for interventions to improve persistence with oral cancer therapies.

Continuous versus intermittent extended adjuvant letrozole for breast cancer: final results of randomized phase III SOLE (Study of Letrozole Extension) and SOLE Estrogen Substudy

BACKGROUND

Late recurrences in postmenopausal women with hormone receptor-positive breast cancers remain an important challenge. Avoidance or delayed development of resistance represents the main objective in extended endocrine therapy (ET). In animal models, resistance was reversed with restoration of circulating estrogen levels during interruption of letrozole treatment. This phase III, randomized, open-label Study of Letrozole Extension (SOLE) studied the effect of extended intermittent letrozole treatment in comparison with continuous letrozole. In parallel, the SOLE estrogen substudy (SOLE-EST) analyzed the levels of estrogen during the interruption of treatment.

PATIENTS AND METHODS

SOLE enrolled 4884 postmenopausal women with hormone receptor-positive, lymph node-positive, operable breast cancer between December 2007 and October 2012 and among them, 104 patients were enrolled in SOLE-EST. They must have undergone local treatment and have completed 4-6 years of adjuvant ET. Patients were randomized between continuous letrozole (2.5 mg/day orally for 5 years) and intermittent letrozole treatment (2.5 mg/day for 9 months followed by a 3-month interruption in years 1-4 and then 2.5 mg/day during all of year 5).

RESULTS

Intention-to-treat population included 4851 women in SOLE (n = 2425 in the intermittent and n = 2426 in the continuous letrozole groups) and 103 women in SOLE-EST (n = 78 in the intermittent and n = 25 in the continuous letrozole groups). After a median follow-up of 84 months, 7-year disease-free survival (DFS) was 81.4% in the intermittent group and 81.5% in the continuous group (hazard ratio: 1.03, 95% confidence interval: 0.91-1.17). Reported adverse events were similar in both groups. Circulating estrogen recovery was demonstrated within 6 weeks after the stop of letrozole treatment.

CONCLUSIONS

Extended adjuvant ET by intermittent administration of letrozole did not improve DFS compared with continuous use, despite the recovery of circulating estrogen levels. The similar DFS coupled with previously reported quality-of-life advantages suggest intermittent extended treatment is a valid option for patients who require or prefer a treatment interruption.

Endocrine Treatment and Targeted Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: ASCO Guideline Update

PURPOSE

To update recommendations of the ASCO systemic therapy for hormone receptor (HR)-positive metastatic breast cancer (MBC) guideline.

METHODS

An Expert Panel conducted a systematic review to identify new, potentially practice-changing data.

RESULTS

Fifty-one articles met eligibility criteria and form the evidentiary basis for the recommendations.

RECOMMENDATIONS

Alpelisib in combination with endocrine therapy (ET) should be offered to postmenopausal patients, and to male patients, with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, ABC, or MBC following prior endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. Clinicians should use next-generation sequencing in tumor tissue or cell-free DNA in plasma to detect PIK3CA mutations. If no mutation is found in cell-free DNA, testing in tumor tissue, if available, should be used as this will detect a small number of additional patients with PIK3CA mutations. There are insufficient data at present to recommend routine testing for ESR1 mutations to guide therapy for HR-positive, HER2-negative MBC. For BRCA1 or BRCA2 mutation carriers with metastatic HER2-negative breast cancer, olaparib or talazoparib should be offered in the 1st-line through 3rd-line setting. A nonsteroidal aromatase inhibitor (AI) and a CDK4/6 inhibitor should be offered to postmenopausal women with treatment-naïve HR-positive MBC. Fulvestrant and a CDK4/6 inhibitor should be offered to patients with progressive disease during treatment with AIs (or who develop a recurrence within 1 year of adjuvant AI therapy) with or without one line of prior chemotherapy for metastatic disease, or as first-line therapy. Treatment should be limited to those without prior exposure to CDK4/6 inhibitors in the metastatic setting.Additional information can be found at www.asco.org/breast-cancer-guidelines.

Chemotherapy-related amenorrhea (CRA) after adjuvant ado-trastuzumab emtansine (T-DM1) compared to paclitaxel in combination with trastuzumab (TH) (TBCRC033: ATEMPT Trial)

PURPOSE

Chemotherapy-related amenorrhea (CRA) is a surrogate for ovarian toxicity and associated risk of infertility and premature menopause. Here, we compare CRA rate with paclitaxel (T)-trastuzumab (H) to that with ado-trastuzumab emtansine (T-DM1).

METHODS

Patients with T1N0 HER2 + early-stage breast cancer (eBC) enrolled on the ATEMPT trial and were randomized 3:1 to T-DM1 3.6 mg/kg IV every (q) 3 weeks (w) × 17 vs. T 80 mg/m² with H IV qw × 12 (4 mg/kg load → 2 mg/kg), followed by H (6 mg/kg IV q3w × 13). Enrollees who self-reported as premenopausal were asked to complete menstrual surveys at baseline and every 6-12 months for 60 months. 18-month CRA (no periods reported during prior 6 months on 18-month survey) was the primary endpoint of this analysis.

RESULTS

Of 512 ATEMPT enrollees, 123 who began protocol therapy and answered baseline and at least one follow-up menstrual survey were premenopausal at enrollment. 76 had menstrual data available at 18 months without having received a gonadotropin-releasing hormone agonist or undergone hysterectomy and/or oophorectomy. Median age was 45 (range 23-53) among 18 who had received TH and 46 (range 34-54) among 58 who had received T-DM1. The 18-month rate of CRA was 50% after TH and 24% after T-DM1 (p = 0.045).

CONCLUSION

Amenorrhea at 18 months was less likely in recipients of adjuvant T-DM1 than TH. Future studies are needed to understand how T-DM1 impacts risk of infertility and permanent menopause, and to assess amenorrhea rates when T-DM1 is administered after standard HER2-directed chemotherapy regimens.

Physical Activity, Weight, and Outcomes in Patients Receiving Chemotherapy for Metastatic Breast Cancer (C40502/Alliance)

Background

Obesity and inactivity are associated with increased risk of cancer-related and overall mortality in breast cancer, but there are few data in metastatic disease.

Methods

Cancer and Leukemia Group B 40502 was a randomized trial of first-line taxane-based chemotherapy for patients with metastatic breast cancer. Height and weight were collected at enrollment. After 299 patients enrolled, the study was amended to assess recreational physical activity (PA) at enrollment using the Nurses' Health Study Exercise Questionnaire. Associations with progression-free survival (PFS) and overall survival (OS) were evaluated using stratified Cox modeling (strata included hormone receptor status, prior taxane, bevacizumab use, and treatment arm). All statistical tests were 2-sided.

Results

A total of 799 patients were enrolled, and at the time of data lock, median follow-up was 60 months. At enrollment, median age was 56.7 years, 73.1% of participants had hormone receptor-positive cancers, 42.6% had obesity, and 47.6% engaged in less than 3 metabolic equivalents of task (MET) hours of PA per week (<1 hour of moderate PA). Neither baseline body mass index nor PA was statistically significantly associated with PFS or OS, although there was a marginally statistically significant increase in PFS (hazard ratio = 0.83, 95% confidence interval = 0.79 to 1.02; P = .08) and OS (hazard ratio = 0.81, 95% confidence interval = 0.65 to 1.02; P = .07) in patients who reported PA greater than 9 MET hours per week vs 0-9 MET hours per week.

Conclusions

In a trial of first-line chemotherapy for metastatic breast cancer, rates of obesity and inactivity were high. There was no statistically significant relationship between body mass index and outcomes. More information is needed regarding the relationship between PA and outcomes.

Expanding Criteria for Prognostic Stage IA in Hormone Receptor-Positive Breast Cancer

BACKGROUND

The prognostic significance of patients with low-risk recurrence score (RS) results in the context of the American Joint Committee on Cancer (AJCC) eighth edition pathologic prognostic staging has not been investigated. We evaluated if expanded RS criteria can be considered for downstaging in AJCC pathologic prognostic staging.

METHODS

Using Surveillance, Epidemiology, and End Results data, we identified patients with T1-3N0-3M0 hormone receptor-positive, HER2-negative breast cancer treated from 2010 to 2015 with follow-up data through 2016. We evaluated TNM categories, grade, and RS result. The primary outcome measured was 5-year disease-specific survival (DSS) of patients with low-risk RS results not already pathologic prognostic stage IA, determined by T and N categories per AJCC eighth edition. All statistical tests were 2-sided.

RESULTS

Of 154 050 patients with median follow-up of 49 months (range = 0-83), RS results were obtained in 60 886 (39.5%): RS was less than 11 in 13 570 (22.3%); 11-17 in 22 719 (37.3%); 18-25 in 16 521 (27.1%); and 26 or higher in 8076 (13.3%). Five-year DSS for pathologic prognostic stage IA patients (n = 114 910, 74.6%) was 98.8%. Among N0-1 patients with a RS less than 18 not staged as pathologic prognostic stage IA by current criteria, 5-year DSS was excellent and not statistically significantly different than for pathologic prognostic stage IA patients (97.2%-99.7%; P > .05). For those with a RS of 18-25, there was a small decrease in DSS for T2N0 (2.3%) and modest decrease for T1-2N1 (4.2%-6.4%) compared with pathologic prognostic stage IA patients (P < .001).

CONCLUSION

Patients with a RS less than 18 have excellent 5-year DSS regardless of T category for N0-1 disease suggesting further modification of the AJCC staging system using this cutoff.

NCCN Guidelines® Insights: Breast Cancer, Version 4.2021

The NCCN Guidelines for Breast Cancer include up-to-date guidelines for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, male breast cancer, and breast cancer during pregnancy. These guidelines are developed by a multidisciplinary panel of representatives from NCCN Member Institutions with breast cancer-focused expertise in the fields of medical oncology, surgical oncology, radiation oncology, pathology, reconstructive surgery, and patient advocacy. These NCCN Guidelines Insights focus on the most recent updates to recommendations for adjuvant systemic therapy in patients with nonmetastatic, early-stage, hormone receptor-positive, HER2-negative breast cancer.

Serial Analysis of Circulating Tumor Cells in Metastatic Breast Cancer Receiving First-Line Chemotherapy

BACKGROUND

We examined the prognostic significance of circulating tumor cell (CTC) dynamics during treatment in metastatic breast cancer (MBC) patients receiving first-line chemotherapy.

METHODS

Serial CTC data from 469 patients (2202 samples) were used to build a novel latent mixture model to identify groups with similar CTC trajectory (tCTC) patterns during the course of treatment. Cox regression was used to estimate hazard ratios for progression-free survival (PFS) and overall survival (OS) in groups based on baseline CTCs, combined CTC status at baseline to the end of cycle 1, and tCTC. Akaike information criterion was used to select the model that best predicted PFS and OS.

RESULTS

Latent mixture modeling revealed 4 distinct tCTC patterns: undetectable CTCs (56.9% ), low (23.7%), intermediate (14.5%), or high (4.9%). Patients with low, intermediate, and high tCTC patterns had statistically significant inferior PFS and OS compared with those with undetectable CTCs (P < .001). Akaike Information Criterion indicated that the tCTC model best predicted PFS and OS compared with baseline CTCs and combined CTC status at baseline to the end of cycle 1 models. Validation studies in an independent cohort of 1856 MBC patients confirmed these findings. Further validation using only a single pretreatment CTC measurement confirmed prognostic performance of the tCTC model.

CONCLUSIONS

We identified 4 novel prognostic groups in MBC based on similarities in tCTC patterns during chemotherapy. Prognostic groups included patients with very poor outcome (intermediate + high CTCs, 19.4%) who could benefit from more effective treatment. Our novel prognostic classification approach may be used for fine-tuning of CTC-based risk stratification strategies to guide future prospective clinical trials in MBC.

NCCN Guidelines Insights: Breast Cancer, Version 3.2018

These NCCN Guidelines Insights highlight the updated recommendations for use of multigene assays to guide decisions on adjuvant systemic chemotherapy therapy for women with hormone receptor-positive, HER2-negative early-stage invasive breast cancer. This report summarizes these updates and discusses the rationale behind them.

Expanding criteria for prognostic stage IA disease in HR+ breast cancer

550

Background: The 8th ed AJCC staging system incorporated grade, receptor status and the Oncotype DX Recurrence Score (RS) result into staging. Based on TAILORx trial data and evidence of utility for RS results in node positive disease, this study was undertaken to determine if staging should incorporate expanded RS criteria. Methods: Patients (pts) with T1-3N0-3 HR+HER2- disease undergoing surgery 2010-15 were identified in the SEER database. 5yr DSS was estimated based on T and N category, grade and RS result; differences were compared between pts with path prognostic stage IA disease and all other groups. Results: 154,054 pts were identified; median follow up was 49 mo (range 0-83). RS results were obtained in 60,886 (39.5%); RS <11 in 13,570 (22.3%) and RS 11-25 in 39,240 (64.5%). The table details 5yr DSS rates. 5yr DSS for path prognostic stage IA pts (n=114,675, 73.4%) was 98.2%. Among all pts with RS <11, 5yr DSS was excellent and not significantly different than for path prognostic stage IA pts. For those with RS 11-25 not receiving chemo, 5yr DSS was inferior to path prognostic stage IA disease for T1-2N1 pts and for those with T2-3N0 disease although among N0 pts the differences were numerically small (1.4%-2.5% vs overall path prognostic stage IA). Conclusions: Pts with Recurrence Score <11 have excellent 5yr DSS regardless of T and N category or grade suggesting further modification of the AJCC staging system using this cutoff. Additional study is required to optimize staging for patients with Recurrence Score 11-25. [Table: see text]

Adjuvant endocrine therapy in postmenopausal women: making treatment choices based on the magnitude of benefit

Hormone-receptor positive, HER2 negative breast cancers account for the vast majority of early stage breast cancers, particularly in postmenopausal women. Adjuvant endocrine therapy is an essential component of multimodality therapy for such cancers, lowering the risk of local-regional and of metastatic recurrence, improving overall survival, and enabling "less" in the way of breast or axillary surgery and radiation therapy for many women. In the past decade, advances in adjuvant endocrine therapy in postmenopausal women include widespread use of aromatase inhibitors instead of or in sequence with tamoxifen, and use of extended durations of endocrine treatment beyond the classical "5 years" of recommended therapy. However, the judicious use of these treatments to optimize outcomes depends on considering features of the tumor stage and biology and careful attention to and management of symptoms related to these treatments.

Treatment-induced symptoms, depression and age as predictors of sexual problems in premenopausal women with early breast cancer receiving adjuvant endocrine therapy

PURPOSE

Sexual dysfunction is an important concern of premenopausal women with early breast cancer. We investigated predictors of sexual problems in two randomized controlled trials.

METHODS

A subset of patients enrolled in TEXT and SOFT completed global and symptom-specific quality-of-life indicators, CES-Depression and MOS-Sexual Problems measures at baseline, six, 12 and 24 months. Mixed models tested the association of changes in treatment-induced symptoms (baseline to 6 months), depression at 6 months, and age at randomization with changes in sexual problems over 2 years.

RESULTS

Sexual problems increased by 6 months and persisted at this level. Overall, patients with more severe worsening of vaginal dryness, sleep disturbances and bone or joint pain at 6 months reported a greater increase in sexual problems at all time-points. Depression scores were significantly associated with sexual problems in the short-term. All other symptoms had a smaller impact on sexual problems. Age was not associated with sexual problems at any time-point.

CONCLUSION

Among several key symptoms, vaginal dryness, sleep disturbance, and bone and joint pain significantly predicted sexual problems during the first 2 years. Early identification of these symptoms may contribute to timely and tailored interventions.