COVID-19 in cancer patients: update from the joint analysis of the ESMO-CoCARE, BSMO, and PSMO international databases

BACKGROUND

COVID-19 has significantly affected patients with cancer and revealed unanticipated challenges in securing optimal cancer care across different disciplines. The European Society for Medical Oncology COVID-19 and CAncer REgistry (ESMO-CoCARE) is an international, real-world database, collecting data on the natural history, management, and outcomes of patients with cancer and SARS-CoV-2 infection.

METHODS

This is the 2nd CoCARE analysis, jointly with Belgian (Belgian Society of Medical Oncology, BSMO) and Portuguese (Portuguese Society of Medical Oncology, PSMO) registries, with data from January 2020 to December 2021. The aim is to identify significant prognostic factors for COVID-19 hospitalization and mortality (primary outcomes), as well as intensive care unit admission and overall survival (OS) (secondary outcomes). Subgroup analyses by pandemic phase and vaccination status were carried out.

RESULTS

The cohort includes 3294 patients (CoCARE: 2049; BSMO: 928, all hospitalized by eligibility criteria; PSMO: 317), diagnosed in four distinct pandemic phases (January to May 2020: 36%; June to September 2020: 9%; October 2020 to February 2021: 41%; March to December 2021: 12%). COVID-19 hospitalization rate was 54% (CoCARE/PSMO), ICU admission 14%, and COVID-19 mortality 22% (all data). At a 6-month median follow-up, 1013 deaths were recorded with 73% 3-month OS rate. No significant change was observed in COVID-19 mortality among hospitalized patients across the four pandemic phases (30%-33%). Hospitalizations and ICU admission decreased significantly (from 78% to 34% and 16% to 10%, respectively). Among 1522 patients with known vaccination status at COVID-19 diagnosis, 70% were non-vaccinated, 24% had incomplete vaccination, and 7% complete vaccination. Complete vaccination had a protective effect on hospitalization (odds ratio = 0.24; 95% confidence interval [0.14-0.38]), ICU admission (odds ratio = 0.29 [0.09-0.94]), and OS (hazard ratio = 0.39 [0.20-0.76]). In multivariable analyses, COVID-19 hospitalization was associated with patient/cancer characteristics, the first pandemic phase, the presence of COVID-19-related symptoms or inflammatory biomarkers, whereas COVID-19 mortality was significantly higher in symptomatic patients, males, older age, ethnicity other than Asian/Caucasian, Eastern Cooperative Oncology Group performance status ≥2, body mass index <25, hematological malignancy, progressive disease versus no evident disease, and advanced cancer stage.

CONCLUSIONS

The updated CoCARE analysis, jointly with BSMO and PSMO, highlights factors that significantly affect COVID-19 outcomes, providing actionable clues for further reducing mortality.

PRECISION: the Belgian molecular profiling program of metastatic cancer for clinical decision and treatment assignment

PRECISION is an initiative from the Belgian Society of Medical Oncology (BSMO) in collaboration with several stakeholders, encompassing four programs that aim to boost genomic and clinical knowledge with the ultimate goal to offer patients with metastatic solid tumors molecularly guided treatments. The PRECISION 1 study has led to the creation of a clinico-genomic database. The Belgian Approach for Local Laboratory Extensive Tumor Testing (BALLETT) and GeNeo studies will increase the number of patients with advanced cancer that have comprehensive genotyping of their cancer. The PRECISION 2 project consists of investigator-initiated phase II studies aiming to provide access to a targeted drug for patients whose tumors harbor actionable mutations in case the matched drug is not available through reimbursement or clinical trials in Belgium.

Current and future diagnostic and treatment strategies for patients with invasive lobular breast cancer

BACKGROUND

Invasive lobular breast cancer (ILC) is the second most common type of breast cancer after invasive breast cancer of no special type (NST), representing up to 15% of all breast cancers.

DESIGN

Latest data on ILC are presented, focusing on diagnosis, molecular make-up according to the European Society for Medical Oncology Scale for Clinical Actionability of molecular Targets (ESCAT) guidelines, treatment in the early and metastatic setting and ILC-focused clinical trials.

RESULTS

At the imaging level, magnetic resonance imaging-based and novel positron emission tomography/computed tomography-based techniques can overcome the limitations of currently used imaging techniques for diagnosing ILC. At the pathology level, E-cadherin immunohistochemistry could help improving inter-pathologist agreement. The majority of patients with ILC do not seem to benefit as much from (neo-)adjuvant chemotherapy as patients with NST, although chemotherapy might be required in a subset of high-risk patients. No differences in treatment efficacy are seen for anti-human epidermal growth factor receptor 2 (HER2) therapies in the adjuvant setting and cyclin-dependent kinases 4 and 6 inhibitors in the metastatic setting. The clinical utility of the commercially available prognostic gene expression-based tests is unclear for patients with ILC. Several ESCAT alterations differ in frequency between ILC and NST. Germline BRCA1 and PALB2 alterations are less frequent in patients with ILC, while germline CDH1 (gene coding for E-cadherin) alterations are more frequent in patients with ILC. Somatic HER2 mutations are more frequent in ILC, especially in metastases (15% ILC versus 5% NST). A high tumour mutational burden, relevant for immune checkpoint inhibition, is more frequent in ILC metastases (16%) than in NST metastases (5%). Tumours with somatic inactivating CDH1 mutations may be vulnerable for treatment with ROS1 inhibitors, a concept currently investigated in early and metastatic ILC.

CONCLUSION

ILC is a unique malignancy based on its pathological and biological features leading to differences in diagnosis as well as in treatment response, resistance and targets as compared to NST.

Preventing taxane-related peripheral neuropathy, pain and nail toxicity: a prospective self-controlled trial comparing hilotherapy with frozen gloves in early breast cancer

PURPOSE

The prevention of taxane-related toxicities at the extremities is highly important for patients' treatment and quality-of-life. Several studies endorse hand/foot-cooling using frozen gloves as a prophylactic intervention. Unlike frozen gloves, hilotherapy produces cooling at a constant temperature. Comparative data with frozen gloves are unavailable.

METHODS

This prospective self-controlled study explores the efficacy of hilotherapy at the right hand and foot compared to frozen gloves at the left in patients with early breast cancer treated with weekly paclitaxel 80 mg/m² or three-weekly docetaxel 75 mg/m². Patient-reported outcomes were collected at baseline, 6, 12, 18 and 24 weeks after the start of treatment. Primary and secondary endpoints were the incidence of any-grade and ≥ grade 2 side-effects (peripheral neuropathy, pain and nail toxicities), and perceived comfort of both interventions.

RESULTS

Sixty-two patients participated. The incidence of any-grade side-effects was similar on both sides, 85.5% with hilotherapy and 90.3% with frozen gloves (p = 1.000). The incidence of ≥ grade 2 side-effects at the extremities was significantly lower with hilotherapy: 43.6% compared to 61.3% with frozen gloves (p = 0.013). Perceived comfort was significantly better for hilotherapy than for frozen gloves (p < 0.0001).

CONCLUSIONS

Compared to frozen gloves, continuous cooling of hands and feet using hilotherapy produces better prevention of ≥ grade 2 patient-reported side-effects at the extremities (peripheral neuropathy, pain and nail toxicities). Perceived comfort was significantly better for hilotherapy. From a clinical and patient perspective, hilotherapy is a better alternative for preventing clinically significant taxane-related side-effects.

Safety of assisted reproductive techniques in young women harboring germline pathogenic variants in BRCA1/2 with a pregnancy after prior history of breast cancer

BACKGROUND

Knowledge is growing on the safety of assisted reproductive techniques (ART) in cancer survivors. No data exist, however, for the specific population of breast cancer patients harboring germline BRCA1/2 pathogenic variants.

PATIENTS AND METHODS

This is a multicenter retrospective cohort study across 30 centers worldwide including women diagnosed at ≤40 years with stage I-III breast cancer, between January 2000 and December 2012, harboring known germline BRCA1/2 pathogenic variants. Patients included in this analysis had a post-treatment pregnancy either achieved through use of ART (ART group) or naturally (non-ART group). ART procedures included ovulation induction, ovarian stimulation for in vitro fertilization or intracytoplasmic sperm injection, and embryo transfer under hormonal replacement therapy.

RESULTS

Among the 1424 patients registered in the study, 168 were eligible for inclusion in the present analysis, of whom 22 were in the ART group and 146 in the non-ART group. Survivors in the ART group conceived at an older age compared with those in the non-ART group (median age: 39.7 versus 35.4 years, respectively). Women in the ART group experienced more delivery complications compared with those in the non-ART group (22.1% versus 4.1%, respectively). No other apparent differences in obstetrical outcomes were observed between cohorts. The median follow-up from pregnancy was 3.4 years (range: 0.8-8.6 years) in the ART group and 5.0 years (range: 0.8-17.6 years) in the non-ART group. Two patients (9.1%) in the ART group experienced a disease-free survival event (specifically, a locoregional recurrence) compared with 40 patients (27.4%) in the non-ART group. In the ART group, no patients deceased compared with 10 patients (6.9%) in the non-ART group.

CONCLUSION

This study provides encouraging safety data on the use of ART in breast cancer survivors harboring germline pathogenic variants in BRCA1/2, when natural conception fails or when they opt for ART in order to carry out preimplantation genetic testing.

Sacituzumab govitecan and trastuzumab deruxtecan: two new antibody-drug conjugates in the breast cancer treatment landscape

BACKGROUND

Two new antibody-drug conjugates (ADCs) containing a topoisomerase I inhibitor payload have recently emerged in the breast cancer (BC) treatment landscape. Sacituzumab govitecan-hziy (SG) is a first-in-class anti-trophoblast cell-surface antigen 2 ADC approved for pretreated metastatic triple-negative breast cancer (mTNBC) and trastuzumab deruxtecan (T-DXd) gained approval for human epidermal growth factor receptor-2 (HER2)-positive advanced BC (aBC). We aim to provide a contemporary review and the current clinical trial landscape of SG and T-DXd in BC.

MATERIALS AND METHODS

We conducted a literature search from Medline database through PubMed, major conference proceedings [abstracts from European Society for Medical Oncology (Breast) Congress, American Society of Clinical Oncology annual meeting, San Antonio Breast Cancer Symposium] and ClinicalTrials.gov with search terms 'sacituzumab govitecan', 'IMMU-132', 'trastuzumab deruxtecan' and 'DS-8201a' up to 21 March 2021.

RESULTS

We assessed 293 records for eligibility, of which 153 were included in this review after screening and exclusion. For SG, efficacy and safety data are available from a phase III trial in pretreated mTNBC and from a phase I/II basket study in mTNBC and hormone receptor-positive/HER2-negative aBC. Thirteen trials with pending primary analysis are ongoing with SG as single agent or in combination, of which 11 are enrolling (2/11 in the early setting). For T-DXd, efficacy/safety data are available as single agent in pretreated HER2-positive (phase Ib and phase II) and in HER2-low aBC (phase Ib), and in combination with nivolumab in HER2-low/positive aBC (phase Ib). Of 23 ongoing trials with T-DXd, 12 are open for enrollment and 3 phase III trials have completed recruitment. The distinct safety profiles of both drugs and their management are discussed.

CONCLUSION

Given their robust single-agent activity, SG and T-DXd are expected to substantially impact treatment standards, both in and far beyond the currently approved indications. Several trials are investigating new treatment settings for both drugs, including a transition to earlier lines and combinations with other anticancer treatments such as immune checkpoint inhibitors.

Assessment of potential process quality indicators for systemic treatment of breast cancer in Belgium: a population-based study

BACKGROUND

Quality indicators (QIs) for the management of breast cancer (BC) have been published in Europe and internationally. In Belgium, a task force was established to select measurable process indicators of systemic treatment for BC, focusing on appropriateness of delivered care. The objective of this study was to evaluate the results of the selected QIs, both nationally and among individual centres.

PATIENTS AND METHODS

Female Belgian residents with unilateral primary invasive BC diagnosed between 2010 and 2014 were selected from the Belgian Cancer Registry database. The national number enabled linkage with the national reimbursement database, which contains information on all reimbursed medical procedures. A total of 12 process indicators were measured on the population and hospital level. Intercentre variability was assessed by median results and interquartile ranges.

RESULTS

A total of 48  872 patients were included in the study. QIs concerning specific BC subtypes only applied to patients diagnosed in 2014 (n = 9855). Clinical stage (cStage) I patients (n = 17 116) were staged with positron emission tomography/computed tomography. Among patients who were pT1aN0 human epidermal growth factor receptor 2 (HER2) positive (n = 47), 25.5% (n = 12) received adjuvant trastuzumab. Among patients with de novo metastatic luminal A/B-like HER2-negative BC (n = 295), 17.3% (n = 51) received upfront chemotherapy. (Neo)adjuvant chemotherapy was administered in 52.4% (n = 12 592) of operated women with cStage I-III, in 37.0% (n = 1270) of operated women with cStage I-III luminal A/B-like HER2-negative BC, and in 19.1% of operated women with cStage I luminal A/B-like HER2-negative BC. In the population of operated patients with cStage I-III, of those younger than 70 years that started adjuvant endocrine therapy (n = 3591), 81.7% (n = 2932) continued treatment for ≥4.5 years. Among patients in cStage I-III older than 70 years (n = 8544), 19.0% (n = 1622) received (neo)adjuvant chemotherapy, whereas among patients with cStage I-III luminal A/B-like HER2-negative BC (n = 1388), 13.0% (n = 181) received (neo)adjuvant chemotherapy. In patients with cStage I-II luminal A/B-like HER2-negative BC older than 70 years (n = 1477), 11.6% (n = 171) were not operated and received upfront endocrine treatment.

CONCLUSION

Well-considered QIs using population-based data can evaluate quality of care and expose disparities among treatment centres. Their use in daily practice should be implemented in all centres treating BC.

Detection of secondary metastatic breast cancer by measurement of plasma CA 15.3

BACKGROUND

Most current guidelines do not recommend the serial analysis of tumour marker CA 15.3 in the follow-up of asymptomatic patients treated for early breast cancer (EBC). These guidelines are based on small-scale studies carried out in an era with more limited treatment options than today. In our large academic centre, serial measurements of CA 15.3 are used routinely in the follow-up of EBC, whereas imaging for distant metastases is only carried out on indication.

PATIENTS AND METHODS

In this retrospective single-centre study, patients were included if they were treated for EBC between 1 January 2000 and 1 January 2018, diagnosed with secondary metastatic disease at least 6 months after initial surgery and had CA 15.3 available at the time of diagnosis of metastases. The primary objective was to evaluate the proportion of patients in whom metastatic disease was discovered by an increasing CA 15.3. Information on the method of metastases detection, CA 15.3 evolution and survival was collected after approval of the ethics committee.

RESULTS

At the moment of diagnosis of metastases, 451 of 730 included patients (62%) had CA 15.3 levels above the upper limit of normal (>30 kU/l). In 269 patients (37%), an increasing CA 15.3 was the first sign that led to the diagnosis of metastases. This was most frequent in luminal A-like tumours (48%) and in liver (45%) and bone (41%) localisation of metastases. By contrast, reported symptoms triggered the diagnosis of metastatic disease in 48% of the patients. Median overall survival was significantly longer when the relapse was discovered by CA 15.3 elevation versus those discovered by another trigger (abnormal clinical examination or history, abnormal laboratory tests or an incidental finding) (35 versus 22 months; P = 0.0027).

CONCLUSION

When CA 15.3 is systematically used in the follow-up of EBC patients, the diagnosis of metastatic disease is made in 37% by a CA 15.3 increase.

The concerns of oncology professionals during the COVID-19 pandemic: results from the ESMO Resilience Task Force survey II

Background

The COVID-19 pandemic has resulted in significant changes to professional and personal lives of oncology professionals globally. The European Society for Medical Oncology (ESMO) Resilience Task Force collaboration aimed to provide contemporaneous reports on the impact of COVID-19 on the lived experiences and well-being in oncology.

Methods

This online anonymous survey (July-August 2020) is the second of a series of global surveys launched during the course of the pandemic. Longitudinal key outcome measures including well-being/distress (expanded Well-being Index—9 items), burnout (1 item from expanded Well-being Index), and job performance since COVID-19 were tracked.

Results

A total of 942 participants from 99 countries were included for final analysis: 58% (n = 544) from Europe, 52% (n = 485) female, 43% (n = 409) ≤40 years old, and 36% (n = 343) of non-white ethnicity. In July/August 2020, 60% (n = 525) continued to report a change in professional duties compared with the pre-COVID-19 era. The proportion of participants at risk of poor well-being (33%, n = 310) and who reported feeling burnout (49%, n = 460) had increased significantly compared with April/May 2020 (25% and 38%, respectively; P < 0.001), despite improved job performance since COVID-19 (34% versus 51%; P < 0.001). Of those who had been tested for COVID-19, 8% (n = 39/484) tested positive; 18% (n = 7/39) felt they had not been given adequate time to recover before return to work. Since the pandemic, 39% (n = 353/908) had expressed concerns that COVID-19 would have a negative impact on their career development or training and 40% (n = 366/917) felt that their job security had been compromised. More than two-thirds (n = 608/879) revealed that COVID-19 has changed their outlook on their work-personal life balance.

Conclusion

The COVID-19 pandemic continues to impact the well-being of oncology professionals globally, with significantly more in distress and feeling burnout compared with the first wave. Collective efforts from both national and international communities addressing support and coping strategies will be crucial as we recover from the COVID-19 crisis. In particular, an action plan should also be devised to tackle concerns raised regarding the negative impact of COVID-19 on career development, training, and job security.

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Compared with survey I, more oncology professionals were at risk of poor well-being (33% versus 25%) and burnout (49% versus 38%).

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Job performance since COVID-19 (JP-CV) has improved from 34% to 51%.

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About 1 in 5 who tested positive for COVID-19 felt they had not been given adequate time to recover before return to work.

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Some 39% expressed concerns that COVID-19 would have a negative impact on their career development or training.

•

More than two-thirds revealed that COVID-19 had changed their outlook on work-personal life balance.

The impact of COVID-19 on oncology professionals: results of the ESMO Resilience Task Force survey collaboration

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on well-being has the potential for serious negative consequences on work, home life, and patient care. The European Society for Medical Oncology (ESMO) Resilience Task Force collaboration set out to investigate well-being in oncology over time since COVID-19.

METHODS

Two online anonymous surveys were conducted (survey I: April/May 2020; survey II: July/August 2020). Statistical analyses were performed to examine group differences, associations, and predictors of key outcomes: (i) well-being/distress [expanded Well-being Index (eWBI; 9 items)]; (ii) burnout (1 item from eWBI); (iii) job performance since COVID-19 (JP-CV; 2 items).

RESULTS

Responses from survey I (1520 participants from 101 countries) indicate that COVID-19 is impacting oncology professionals; in particular, 25% of participants indicated being at risk of distress (poor well-being, eWBI ≥ 4), 38% reported feeling burnout, and 66% reported not being able to perform their job compared with the pre-COVID-19 period. Higher JP-CV was associated with better well-being and not feeling burnout (P < 0.01). Differences were seen in well-being and JP-CV between countries (P < 0.001) and were related to country COVID-19 crude mortality rate (P < 0.05). Consistent predictors of well-being, burnout, and JP-CV were psychological resilience and changes to work hours. In survey II, among 272 participants who completed both surveys, while JP-CV improved (38% versus 54%, P < 0.001), eWBI scores ≥4 and burnout rates were significantly higher compared with survey I (22% versus 31%, P = 0.01; and 35% versus 49%, P = 0.001, respectively), suggesting well-being and burnout have worsened over a 3-month period during the COVID-19 pandemic.

CONCLUSION

In the first and largest global survey series, COVID-19 is impacting well-being and job performance of oncology professionals. JP-CV has improved but risk of distress and burnout has increased over time. Urgent measures to address well-being and improve resilience are essential.

Features of durable response and treatment efficacy for capecitabine monotherapy in advanced breast cancer: real-world evidence from a large single-centre cohort

PURPOSE

In metastatic breast cancer (MBC) population treated with capecitabine monotherapy, we investigated clinical-pathological features as possible biomarkers for the oncological outcome.

METHODS

Retrospective study of consecutive MBC patients treated at University Hospitals Leuven starting capecitabine between 1999 and 2017. The primary endpoint was the durable response (DR), defined as non-progressive disease for > 52 weeks. Other main endpoints were objective response rate (ORR), time to progression (TTP) and overall survival (OS).

RESULTS

We included 506 patients; mean age at primary breast cancer diagnosis was 51.2 years; 18.2% had de novo MBC; 98.8% were pre-treated with taxanes and/or anthracycline. DR was reached in 11.6%. Patients with DR, as compared to those without DR, were more likely oestrogen receptor (ER) positive (91.5% vs. 76.8%, p = 0.010) at first diagnosis, had a lower incidence of lymph node (LN) involvement (35.6% vs. 49.9%, p = 0.039) before starting capecitabine, were more likely to present with metastases limited to ≤ 2 involved sites (54.2% vs. 38.5%, p = 0.020) and time from metastasis to start of capecitabine was longer (mean 3.5 vs. 2.7 years, p = 0.020). ORR was 22%. Median TTP and OS were 28 and 58 weeks, respectively. In multivariate analysis (only performed for TTP), ER positivity (hazard ratio (HR) = 0.529, p < 0.0001), HER2 negativity (HR = 0.582, p = 0.024), absence of LN (HR = 0.751, p = 0.008) and liver involvement (HR = 0.746, p = 0.013), older age at capecitabine start (HR = 0.925, p < 0.0001) and younger age at diagnosis of MBC (HR = 0.935, p = 0.001) were significant features of longer TTP.

CONCLUSION

Our data display relevant clinical-pathological features associated with DR and TTP in patients receiving capecitabine monotherapy for MBC.

Scalp cooling in breast cancer patients treated with docetaxel-cyclophosphamide: patient- and nurse-reported results

PURPOSE

Recent evidence supports the efficacy of scalp cooling in preventing chemotherapy-induced alopecia in breast cancer treatments. However, efficacy largely varies between treatment regimens. The aim of this study was to explore the patient- and nurse-reported results of scalp cooling in terms of hair loss and need for a wig/head cover in patients with breast cancer treated with 3-weekly docetaxel 75 mg/m²- cyclophosphamide 600 mg/m².

METHODS

We studied nurse-reported efficacy as noted in the electronic patient files of 85 patients treated with docetaxel 75 mg/m²- cyclophosphamide 600 mg/m² between 1/1/2017 and 1/1/2020. Sixty-nine of them also self-reported on their scalp cooling results up to one year after adjuvant chemotherapy in a retrospective way.

RESULTS

Nurse- and patient-reported data showed that scalp cooling was successful (i.e., hair loss < 50%) in 47.1 and 44.9% of patients, respectively, and 55% of patients were (very) satisfied with the result of scalp cooling. Scalp cooling was perceived as (very) uncomfortable in 36.2% of patients. Regarding hair status one year after treatment, 47 patients (55.3%) reported no changes compared to their hair status before treatment.

CONCLUSIONS

Scalp cooling is successful in preventing severe chemotherapy-induced alopecia in almost half of the patients with breast cancer treated with docetaxel 75 mg/m²- cyclophosphamide 600 mg/m². Better understanding of the success rate of scalp cooling enables correct patient information and decision-making support.

Efficacy of anti-HER2 therapy in metastatic breast cancer by discordance of HER2 expression between primary and metastatic breast cancer

PURPOSE

In stage IV breast cancer, the efficacy of human epidermal growth factor receptor 2 (HER2) targeted therapies in cases with discordance in HER2 expression between primary and metastatic site is not well known. We studied progression free (PFS) and overall survival (OS) by HER2 concordance when treating women with taxane-trastuzumab (± pertuzumab) in first or second line and trastuzumab-emtansine (T-DM1) or capecitabine-lapatinib in later lines.

PATIENTS AND METHODS

Retrospective monocentric study including all breast cancer patients receiving trastuzumab between January 2002 and September 2017 at the University Hospital in Leuven; we selected metastatic patients with an available HER2 status in primary and metastatic site. The Kaplan-Meier method was used for estimating PFS/OS and log-rank test for analyzing between group differences. A Cox model is used for testing difference between groups while correcting for Pertuzumab. Multivariable Cox regression is used to model overall survival as a function group, correcting for possible confounders.

RESULTS

We included 74 patients; 46 had an unchanged HER2 status (positive/positive), 9 lost HER2 (positive/negative), while 19 acquired HER2 amplification (negative/positive). 25 out of 28 cases with a discordant HER2 status were positive for ER and/or PgR in the primary site. HER2 positive/negative cases had a significantly lower PFS for taxane-trastuzumab-(pertuzumab) (PFS = 5.5 months), compared to HER2 positive/positive (PFS 9 months, p = 0.01) and HER2 negative/positive (PFS 14 months, p = 0.01) patients. PFS for later line T-DM1 (n = 30) was significantly higher for the HER2 positive/positive group (PFS 6.0 months) than for the discordant groups HER2 negative/positive (PFS 1.0 month, p = 0.04) and HER2 positive/negative (PFS 1.5 month, p = 0.01). After correcting for possible confounders, the HER2 positive/negative group had a significantly worse OS compared to HER2 positive/positive (HR 0.19, 95% CI 0.08-0.44) and negative/positive (HR 0.15, 95% 0.06-0.38).

CONCLUSION

Conversion of HER2 status was seen in 28 out of 74 cases and was mostly observed in hormone receptor-positive tumors. In contrast to patients with HER2 loss, patients with a positive conversion of HER2 status derived substantial benefit from first line treatment with taxane-trastuzumab-(pertuzumab). This study highlights the importance of re-biopsying the metastatic lesion and changing treatment according to the last HER2 result.

Intra-arterial Mitomycin C infusion in a large cohort of advanced liver metastatic breast cancer patients: safety, efficacy and factors influencing survival

PURPOSE

The aim of this study was to determine the safety and efficacy of Mitomycin C (MMC) infusion in a large cohort of advanced liver metastatic breast cancer patients (LMBC) and to determine factors influencing overall survival (OS).

METHODS

We retrospectively analysed LMBC patients, treated with MMC infusion between 2000 and 2017. Hepatic response was measured with baseline CT scans and first available CT scan after MMC infusion by RECIST 1.1 criteria. Adverse events were registered by the CTCAE version 5.0. OS and hepatic progression free survival (hPFS) were evaluated using Kaplan-Meier estimates. After univariable analysis, a stepwise forward multivariable (MV) prediction analysis was developed to select independent pre-treatment factors associated with OS.

RESULTS

We included 176 patients with a total of 599 MMC infusions, mostly heavily pre-treated patients with a median time from diagnosis of MBC to MMC infusion of 36.9 months. RECIST evaluation of liver lesions (n = 132) showed a partial response rate of 15%, stable disease of 43% and progressive disease in 17%. Adverse events grade 3 and 4 were reported in 17.5%. Median PFS was 5.5 months and median OS was 7.8 months. Significant independent baseline predictors of worse OS included number of prior systemic chemotherapy lines, prior liver ablation, higher liver tumour burden and elevated levels of bilirubin and ALT.

CONCLUSION

MMC infusion is safe and effective in advanced LMBC patients. An increased number of prior therapies, a higher liver tumour burden and elevated levels of bilirubin and ALT were associated with a worse OS.

Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program

Background

Male breast cancer (BC) is rare, managed by extrapolation from female BC. The International Male BC Program aims to better characterize and manage this disease. We report the results of part I, a retrospective joint analysis of cases diagnosed during a 20-year period.

Methods

Patients with follow-up and tumor samples, treated between 1990 and 2010, in 93 centers/9 countries. Samples were centrally analyzed in three laboratories (the United Kingdom, the Netherlands and the United States).

Results

Of 1822 patients enrolled, 1483 were analyzed; 63.5% were diagnosed between 2001 and 2010, 57 (5.1%) had metastatic disease (M1). Median age at diagnosis: 68.4 years. Of 1054 M0 cases, 56.2% were node-negative (N0) and 48.5% had T1 tumors; 4% had breast conserving surgery (BCS), 18% sentinel lymph-node biopsy; half received adjuvant radiotherapy; 29.8% (neo)adjuvant chemotherapy and 76.8% adjuvant endocrine therapy (ET), mostly tamoxifen (88.4%). Per central pathology, for M0 tumors: 84.8% ductal invasive carcinomas, 51.5% grade 2; 99.3% estrogen receptor (ER)-positive; 81.9% progesterone receptor (PR)-positive; 96.9% androgen receptor (AR)-positive [ER, PR or AR Allred score ≥3]; 61.1% Ki67 expression low (<14% positive cells); using immunohistochemistry (IHC) surrogates, 41.9% were Luminal-A-like, 48.6% Luminal-B-like/HER-2-negative, 8.7% HER-2-positive, 0.3% triple negative. Median follow-up: 8.2 years (0.0-23.8) for all, 7.2 years (0.0-23.2), for M0, 2.6 years (0.0-12.7) for M1 patients. A significant improvement over time was observed in age-corrected BC mortality. BC-specific-mortality was higher for men younger than 50 years. Better overall (OS) and recurrence-free survival (RFS) were observed for highly ER+ (P = 0.001), highly PR+ (P = 0.002), highly AR+ disease (P = 0.019). There was no association between OS/RFS and HER-2 status, Ki67, IHC subtypes nor grade.

Conclusions

Male BC is usually ER, PR and AR-positive, Luminal B-like/HER2-negative. Of note, 56% patients had T1 tumors but only 4% had BCS. ER was highly positive in >90% of cases but only 77% received adjuvant ET. ER, PR and AR were associated with OS and RFS, whereas grade, Ki67 and IHC surrogates were not. Significant improvement in survival over time was observed.

Abstract PD3-09: Efficacy of HER2 inhibitors in metastatic breast cancer by discordance in HER2 amplification status between primary and metastatic breast cancer

Purpose:

In stage IV breast cancer (BC), discordance in the human epidermal growth factor receptor 2 (HER2) amplification status between primary and metastatic BC might affect efficacy of HER2-targeted agents. We studied progression free (PFS) and overall survival (OS) dependent on HER2 concordance in patients treated with a first line taxane-trastuzumab combination and later line trastuzumab-emtansine (T-DM1).

Patients and Methods:

This retrospective monocentric study included 76 patients with metastatic BC under treatment with trastuzumab in which a biopsy from both the primary and metastatic site was available. HER2 amplification status, sex-steroid receptor status, Nottingham prognostic index, distant metastasis-free interval and consecutive lines of therapy were retrieved from patients' reports. The Kaplan-Meier method was used for estimating PFS/OS and log-rank test for analyzing between group differences. A Cox model is used for testing difference between groups while correcting for Pertuzumab. Multivariable Cox regression is used to model OS as a function group, correcting for possible confounders.

Results:

Discordance in HER2 amplification status was seen in 30 out of 76 patients (39%), 11 patients lost HER2 amplification in the metastatic lesion (HER2lost) while 19 acquired HER2 amplification (HER2acquired). The other 46 patients had a HER2 amplification on both primary and metastatic site (HER2stable). The HER2lost group had a significant lower median PFS (PFS= 5.5 months) for taxane-trastuzumab, after correcting for pertuzumab, compared to the HER2stable group (PFS= 9 months, corrected p= 0.0146) and HER2acquired group (PFS=14 months, corrected p=0.0121). For T-DM1 treatment, both discordant groups, HER2acquired (PFS=1.1 months, p=0.0373) and HER2lost (PFS=1.5 months, p=0.0116), had a significant lower PFS compared to the HER2stable group (PFS=6.0 months). After correcting for possible confounders, HER2lost had a significant worse OS compared to HER2stable (HR 0.187, 95% CI 0.079 – 0.439) and HER2acquired (HR 0.147, 95% 0.058-0.378).

Conclusion:

Loss of HER2 amplification in metastatic lesions seems to have a negative predictive value for PFS on HER2-targeted agents and negative prognostic impact on OS. Acquiring of HER2 amplification was predictive for lower PFS on T-DM1 but wasn't predictive for lower PFS on taxane-trastuzumab.

Citation Format: Van Raemdonck E, Berteloot P, Laenen A, Han S, Van Nieuwenhuysen E, Salihi R, Concin N, Vergote I, Floris G, Wildiers H, Punie K, Neven P. Efficacy of HER2 inhibitors in metastatic breast cancer by discordance in HER2 amplification status between primary and metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-09.

Abstract P3-03-32: Monocentric experience with the sentinel lymph node biopsy prior to neoadjuvant chemotherapy in clinically lymph node negative early breast cancer

Background

In patients with clinically lymph node negative (cN0) early breast cancer (EBC) treated with neoadjuvant chemotherapy (NACT), the sentinel lymph node biopsy (SLNB) can be performed before or after NACT. We report safety of axillary staging performing the SLNB prior to NACT in cN0 EBC and estimate NACT-induced downstaging to ypN0 in previously NACT-treated cN1 EBC, to make an assumption for avoiding axillary lymph node dissection (ALND) if SLNB was done after NACT.

Patients and Methods

Monocentric retrospective study of consecutive triple negative (TNBC) and HER-2 amplified BC patients treated with standard NACT. cN0 patients had SLNB before NACT followed by local therapy. Axillary lymph node dissection (ALND) post-NACT was performed in all cN1 and in cN0 cases with a positive or failed SLNB. Using descriptive statistics, we here report SLNB-detection and SLNB-positive rate, SLNB-operative complications, complete tumor regression in the breast (ypT0/is) and disease-free survival (DFS) for cN0 cases and NACT-induced downstaging to ypN0 in previously NACT-treated cN1 EBC.

Results

We included 245 NACT-treated patients; 119 cN0 and 126 cN1. SLNB-detection rate in cN0 cases was 99,2%; 25 or 21% had ≥ 1 involved SLN, 21.8% experienced SLNB related-complications (e.g. infection, seroma, hematoma) leading to NACT-delay in 3 and interruption in 1 patient. Median start of NACT after SLNB was 7 days (range 1-20 days). In patients with a positive SLNB, there were no additional involved nodes in the ALND. In 5 of these patients, therapy response in a lymph node was described. Complete tumor regression in the breast (ypT0/is) was 52% in SLNB-positive and 59,1% in SLNB-negative cN0 cases. NACT-induced ypN0 was 61% in cN1 cases. At 30 months of median follow-up (range 1-86 months), DFS was 93,2% (4.2% metastatic; no axillary relapse) in cN0 cases. Median DFS was better for patients with complete tumor regression in the breast as compared to those with partial response; 95.6% and 90% respectively.

Conclusion

In conclusion, performing SLNB before NACT in cN0 cases is a safe and accurate method. While some pN1(sn) could have avoid ALND by NACT-induced axillary down-staging, based on our assumption, long term follow-up is needed to conclude whether SLNB after NACT is safe.

Keywords: Breast cancer, neoadjuvant chemotherapy, timing sentinel lymph node biopsy

Citation Format: Delameilleure M, Smeets A, Nevelsteen I, Han S, Van Nieuwenhuysen E, Berteloot P, Hoste G, Salihi R, Van Ongeval C, Keupers M, Prevos R, Wildiers H, Punie K, Van Limbergen E, Weltens C, Janssen H, Floris G, Vergote I, Neven P. Monocentric experience with the sentinel lymph node biopsy prior to neoadjuvant chemotherapy in clinically lymph node negative early breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-32.

Abstract P4-02-07: Comparison of breast cancer molecular subtyping by Immunohistochemistry and by BluePrint® next generation RNA sequencing-based test at University Hospitals Leuven and Curie Institute Paris

Background

MammaPrint® (MP) and BluePrint® (BP) are microarray-based tests with MP being prognostic for distant recurrence and BP enabling stratification into breast cancer molecular subtypes (Luminal, HER2, Basal-type). Recently, a CE marked MP and BP targeted RNA Next Generation Sequencing (NGS)-based kit was developed at Agendia and validated at University Hospitals Leuven and Curie Institute Paris. Here we compare breast cancer molecular subtype stratification defined by immunohistochemistry (IHC) and by MP and BP NGS- and microarray- based tests.

Patients and Methods

In this study, 124 primary operable invasive breast cancer patients were included at University Hospitals Leuven and at Curie Institute (n=80 Leuven; n=44 Curie) with the following histological subtypes: ductal-NOS (n=100), lobular (n=16), mucinous (n=3), tubular (n=2), others (n=3). Patients with bilateral breast cancer or with &gt;3 positive lymph nodes were excluded. Surrogate breast cancer subtypes based on IHC were defined as follows: luminal if ≥10% estrogen receptor (ER) expression; triple negative if &lt;10% ER and progesterone receptor (PR) expression and HER2 stained negative by IHC and/or FISH; HER2+ if HER2 receptor stained positive (2+ or 3+) by IHC and/or FISH. Luminal subtypes were further stratified into Luminal A-like (HER2 negative, Ki-67&lt;14%, PR≥20%) and Luminal B-like (HER2 negative or positive, Ki-67 ≥14%, PR&lt;20%). When Ki-67% was not available, tumors with grade 1 or 2 were classified as Luminal A-like and with grade 3 as Luminal B-like. IHC subtypes were compared to the BP NGS and microarray molecular subtypes (Luminal-, HER2- and Basal-type). To further stratify BP luminal type tumors, MP test was used as follows: Luminal A (BP Luminal and MP low risk) and Luminal B (BP Luminal and MP high risk).

Results

Concordance between IHC and MP/BP NGS subtyping was 75.0% (93/124), while concordance between MP/BP on NGS and microarray was 89.5% (111/124). MP/BP NGS subtyping identified more low risk Luminal A tumors compared to IHC (54.0%, (67/124) vs 44.3% (55/124)). Notably, concordance was excellent for triple-negative and, to less extent for HER2 driven tumors (Luminal B-like-HER2 positive and HER2+).

IHC vs. MP/BP NGS molecular subtyping (n=124)  MP/BP NGSIHCLuminal ALuminal BHER2-positiveBasalTotalLuminal A-like4690055Luminal B-like, HER2-negative16210037Luminal B-like, HER2-positive565016HER2-positive00303Triple negative0101213Total6737812124Microarray vs MP/BP NGS molecular subtyping (n=124)  MP/BP NGSMicroarrayLuminal ALuminal BHER2 positiveBasalTotalLuminal A6040064Luminal B7310038HER2-positive028010Basal0001212Total6737812124

Conclusion

This study shows a discordance of 25.0% between IHC and BP/MP NGS subtyping. This is in line with previous findings where IHC was compared to molecular subtyping based on microarray (Viale 2017, Whitworth 2014) underlining the complementarity of genomic testing in early stage breast cancer. Moreover, we observed a high concordance between NGS and microarray molecular subtyping, which suggests a successful translation of the MP/BP microarray test to a MP/BP NGS test.

Citation Format: Darrigues L, Slembrouck L, Mittempergher L, Delahaye LJ, Vanden Bempt I, Vander Borght S, Vliegen L, Sintubin P, Raynal V, Bohec M, Reyes C, Rapinat A, Helsmoortel C, Jongen L, Hoste G, Neven P, Wildiers H, Smeets A, Nevelsteen I, Punie K, Van Nieuwenhuysen E, Han S, Laurent C, Vincent-Salomon A, Laas-Faron E, Witteveen AT, Neijenhuis S, Glas AM, Floris G, Reyal F. Comparison of breast cancer molecular subtyping by Immunohistochemistry and by BluePrint® next generation RNA sequencing-based test at University Hospitals Leuven and Curie Institute Paris [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-02-07.

Abstract P4-08-25: Decentralized beta testing of MammaPrint and BluePrint NGS kit at University Hospitals Leuven and Curie Institute Paris

Background

Many countries restrict patient material exchange to central diagnostic laboratories abroad, limiting access to assays like MammaPrint® (MP) and BluePrint® (BP). Both assays are microarray-based, with MP being prognostic for distant recurrence and BP for molecular subtyping of breast cancer (Luminal-, HER2-, and Basal-type). To increase accessibility, decentralization is required with Next Generation Sequencing (NGS) being the preferred testing platform given that most diagnostic laboratories have the technology in place. The aim of this beta testing study is to validate a previously developed and centrally validated MP and BP NGS kit for RNA samples in two large tertiary academic hospitals in Europe.

Patients and Methods

Patients with early breast cancer diagnosed at the Multidisciplinary Breast Center at University Hospitals Leuven and Curie Institute Paris were prospectively included between September 2017 and January 2018. Patients with bilateral breast cancer or presenting with more than 3 positive lymph nodes were excluded. Only patients with invasive ductal and invasive lobular carcinoma were included. Twenty tissue sections were cut from formalin-fixed, paraffin-embedded (FFPE) blocks; 10 tissue sections were analyzed at the local site using the MP and BP NGS kit, and 10 tissue sections were analyzed at Agendia using the same kit and procedure, as well as with the golden standard method (gene expression microarrays). Targeted RNA sequencing of the 70 MP and 80 BP signature genes was performed on Illumina MiSeq instruments. The raw NGS data generated at the local test sites was sent through a secure file transfer protocol server to Agendia for interpretation and comparison with microarray and NGS performed in the Agendia laboratories. We aimed for a minimum concordance rate between MP and BP outcome of 90% between each local site and Agendia's centralized site.

Results

In this study, 116 early breast cancer patients were included (73 from University Hospitals Leuven and 43 from Curie Institute). Out of these patients, 52% were MP Low Risk and 48% MP High Risk according to microarray. The patients had a BP luminal, HER2 or basal subtype in respectively 83%, 9% and 8%. Concordance between MP microarray obtained from Agendia and MP NGS obtained from the local sites was 91.4%. Concordance between MP High and Low Risk classification between NGS Leuven versus NGS Agendia was 92.1% and between NGS Curie versus NGS Agendia 95.3%. For BP subtype outcomes, the results from microarray versus NGS for all patients combined from both local sites gave a 98.3% concordance and NGS Agendia versus NGS from each local site gave a 100% concordance.

Conclusion

The MP and BP NGS kit was successfully validated in a decentralized setting, showing high concordance between results obtained at three different sites. There was a clear benefit of having well-trained NGS experienced diagnostic technical teams. The MP and BP NGS kit the first FFPE targeted RNA sequencing based multigene signature for breast cancer care, will provide a high and equal standard of MP and BP gene expression testing for breast cancer in a decentralized setting.

Citation Format: Slembrouck L, Laurent C, Delahaye LJ, Mittempergher L, Vanden Bempt I, Vander Borght S, Darrigues L, Vliegen L, Sintubin P, Raynal V, Bohec M, Reyes C, Rapinat A, Helsmoortel C, Jongen L, Hoste G, Neven P, Wildiers H, Smeets A, Nevelsteen I, Punie K, Van Nieuwenhuysen E, Han S, Salomon AV, Faron EL, Cynober T, Witteveen AT, Neijenhuis S, Glas AM, Reyal F, Floris G. Decentralized beta testing of MammaPrint and BluePrint NGS kit at University Hospitals Leuven and Curie Institute Paris [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-25.

Abstract P1-15-04: Breast cancer recurrence and predictors for recurrence despite pathologic complete response following neoadjuvant chemotherapy

Introduction

Breast cancer patients with a high-risk tumor (for example Triple Negative Breast Cancer) who achieve a pathological complete response (pCR) following neoadjuvant chemotherapy (NACT) have a better outcome compared to patients with residual disease at surgery. This study investigated Breast Cancer Free Survival (BCFS) and predictors for distant relapse despite pCR.

Methods

Monocentric retrospective study of 243 consecutive breast cancer patients who achieved pCR (ypT0/is ypN0/N0(i+)) after treatment with NACT in UZ Leuven between 01/2000 and 08/2017. 58% had stage III breast cancer, 40% Triple Negative Breast Cancer (TNBC) and 47% HER2 pos breast cancer. BCFS was defined as any breast cancer related event (local, contra-lateral, regional, metastatic) that first appeared. Primary endpoints were frequency of BCFS and predictors for metastatic relapse: patient demographics (age, body mass index (BMI)) and tumor characteristics (TNM stage, histological type, hormonal receptor status). Secondary endpoints were breast cancer specific survival (BCSS) and overall survival (OS). Statistical analysis was performed using the Statistical Package for the Social Sciences software (SPSS, version 25). The Kaplan Meier method was used for survival analysis.

Results

Of 1167 breast cancer patients undergoing neoadjuvant treatment, 243 patients (20,8%) achieved pCR and were included. Median follow up was 57 months (range 9-252 months). 22 (9.1%) developed tumor progression; 20 (8.2%) metastatic and 2 (0.8%) contralateral. First metastatic site was the brain in 11/20 patients (55%) and 14/22 (64%) died of breast cancer. Higher clinical tumor stage at diagnosis predicted metastatic relapse (stage I-II 2.9%; stage III 12.1%). Patients with a BMI ≤25 kg/m2 had less metastatic relapse than patients with BMI &gt;25kg/m2 (3.8% versus 12.0%), better OS (94.6% vs 88.0%) and BCSS (97.7 vs 91.7%). Neither tumor type (TNBC 8.2%; HER2-pos 8.1%; HR-pos/HER2 neg 9.3%) nor younger age &lt; 36yrs (3.3% versus 8.9%) was prognostic for post-pCR relapse. There is a lower OS (mean 174m versus 231m, 95% CI 158-190m, median 208m) and BCSS (mean 191m versus 253m, 95% CI 182-200m) in cN1-3 versus cN0 disease at diagnosis.

Conclusion

Despite NACT-induced pCR, a small proportion (9.1%) will develop a metastatic relapse after a median follow-up of 57 months. We found that a higher stage at diagnosis and a higher BMI were prognostic for worse BCFS while age &lt;36 y and negative hormonal receptor status were not prognostic. cN+ at diagnosis and a BMI &gt;25 predict worse OS and BCSS.

Citation Format: Borremans K, Berteloot P, Van Nieuwenhuysen E, Han S, Hoste G, Wildiers H, Punie K, Smeets A, Nevelsteen I, Floris G, Van Ongeval C, Keupers M, Prevos R, Van Limbergen E, Menten J, Weltens C, Janssen H, Vergote I, Neven P. Breast cancer recurrence and predictors for recurrence despite pathologic complete response following neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-04.

Abstract P5-09-05: Hereditary breast cancer beyond BRCA: Clinical and histopathological characteristics in patients with germline CHEK2, ATM, PALB2 and TP53-mutations

Background

The introduction of multi-gene panel testing in the diagnosis of hereditary breast and ovarian cancer (HBOC) has led to an important increase in the detection of breast cancer predisposition genes other than BRCA1 and BRCA2.

Methods

All individuals who underwent HBOC-testing at our institution since the introduction of multi-gene panel testing were included (March 2016-August 2017). In this retrospective analysis, the BRCA Hereditary Cancer MASTR Plus® panel is used (Multiplicom, Belgium), with sequencing of BARD1, BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, TP53, MRE11A, RAD50, NBN, FAM175A, ATM, PALB2, STK11, MEN1, PTEN, CDH1, MUTYH, CHEK2, BLM, XRCC2, EPCAM, MLH1, MSH6, PMS2, MSH2.

In breast cancer patients with a recurrent germline alteration, age and TNM stage at diagnosis, histological subtype, grade of differentiation and molecular surrogate subtype were recorded. Given the low numbers of TP53-carriers diagnosed by HBOC testing, also patients with a germline TP53-mutation diagnosed by targeted sequencing at our institution were included. Statistical analysis were performed with SPSS version 25.

Results

In 11.9 % of 2806 patients who underwent panel testing, a germline pathogenic alteration was detected. BRCA1 and BRCA2 were the most prevalent alterations, detected in respectively 3.35 and 2.92 % of patients. Germline alterations in CHEK2, ATM , PALB2 and TP53 were detected in respectively 2.5 %, 1.1 %, 0.5 % and 0.1 %. In 1 % of patients, germline alterations were retrieved that only contribute to ovarian cancer risk (BRIP, RAD51C, RAD51D). Germline DNA mismatch repair alterations were detected in 0.39 % of patients.

The median age at onset of breast cancer in patients with germline CHEK2-, ATM-, PALB2- and TP53-mutations was 47, 53, 39 and 33 years respectively. The age of breast cancer diagnosis in patients with germline TP53-alterations was significantly younger compared to patients with CHEK2-mutations (p = 0.01), ATM-mutations (p = 0.01) and PALB2-mutations (p = 0.04). In situ carcinomas were diagnosed in respectively 9 %, 11 % and 11 % of patients with CHEK2-, PALB2- and TP53-mutations. Patients with CHEK2, ATM, PALB2 and TP53-alterations were diagnosed with ≥T3-tumors in respectively 13 %, 12 %, 33 % and 22 %. Nodal status at diagnosis was negative in 40-60 % in these 4 subgroups. Upfront metastatic disease was diagnosed only in 2/43 CHEK2-carriers. More than half of the breast cancer diagnoses were luminal tumors in CHEK2-, ATM- and PALB2-carriers, while cases with germline TP53-alterations only presented with luminal cancers in 22 % in our series.

Conclusion

Almost half of the pathogenic mutations detected in HBOC-genes are alterations in genes other than BRCA1 and BRCA2. CHEK2-mutations are by far the most prevalent, followed by ATM, PALB2 and TP53.

The range of the CHEK2- and ATM-population was wider then expected at the lower-age boundary. The age of breast cancer diagnosis in patients with germline TP53-mutations was significantly younger compared to patients with CHEK2-, ATM- and PALB2-mutations. The distribution of the histological subtypes and grade of differentiation was not suggestive of a specific correlation with germline mutation status.

Citation Format: Hoste G, D'Hoore P, Legius E, Van Buggenhout G, Floris G, Wildiers H, Han SN, Van Nieuwenhuysen E, Berteloot P, Smeets A, Nevelsteen I, Weltens C, Janssen H, Van Limbergen E, Neven P, Punie K. Hereditary breast cancer beyond BRCA: Clinical and histopathological characteristics in patients with germline CHEK2, ATM, PALB2 and TP53-mutations [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-05.

Palbociclib in highly pretreated metastatic ER-positive HER2-negative breast cancer

PURPOSE

We aimed to investigate the role of palbociclib, a first-in-class cyclin-dependent kinase 4 and 6 inhibitor, in postmenopausal women with highly pretreated endocrine therapy-resistant metastatic breast cancer (MBC).

METHODS

Between 28 September 2015 and 14 March 2017, a compassionate use program was established in the University Hospitals Leuven in which 82 postmenopausal women with estrogen receptor-positive, HER2-negative MBC were included after at least four lines of systemic treatment. The efficacy and safety analysis was performed in 82 patients who had received at least one dose of palbociclib and who had at least 6-month follow-up at the data cut-off point. The primary objective was the evaluation of efficacy of the combination of palbociclib and endocrine therapy with clinical benefit as primary endpoint, defined as the absence of progressive disease and being on treatment for at least 6 months. Secondary objectives were the evaluation of toxicity and the identification of potential predictors for clinical benefit.

RESULTS

The median age of the patients was 67.1 years (range 34.8-85.9) at the time of inclusion. The average duration of treatment was 5.6 months (range 1-19), with a median progression-free survival of 3.17 (95% CI 2.76-4.70) months. At the data cut-off point, 10 patients were still on treatment with palbociclib. In this highly pretreated setting, 34 patients experienced no progressive disease within 6 months, resulting in an overall clinical benefit rate (CBR) of 41.5%. 20.7% (17/82) showed stable disease for ≥ 9 months and 13.4% for ≥ 12 months. None of the investigated predicting factors were significantly associated with clinical benefit at 6 months. For 43.9% of the patients, treatment delay or dose reduction was indicated.

CONCLUSIONS

Palbociclib in combination with endocrine therapy shows an unexpectedly high CBR and favorable safety profile in heavily pretreated endocrine-resistant estrogen receptor-positive, HER2-negative MBC patients.

Abstract P5-21-22: Palbociclib in highly pretreated metastatic ER-positive HER-2 negative breast cancer

Palbociclib, a first-in-class CDK 4/6 inhibitor, in combination with letrozole or fulvestrant is now licensed for the first or second line treatment of postmenopausal women with hormone-sensitive HER-2 negative metastatic breast cancer (MBC), but its activity in later lines is unknown. In Belgium, a compassionate Use Program (CUP) was temporarily established to provide palbociclib after at least 4 lines of systemic treatment for MBC.

The UZ Leuven Multidisciplinary Breast Center included 82 patients in this CUP from September 28th 2015 to March 14th 2017. This analysis describes retrospectively collected efficacy (Revised RECIST guideline, version 1.1) and safety data from 68 patients with at least 6 months follow-up at the data cut-off point. The primary endpoint was clinical benefit, defined as being on treatment for at least 6 months (CR + PR + SD). Most of the patients (89.7%) used palbociclib in combination with letrozole. Other combinations are with tamoxifen (2.9%), fulvestrant (2.9%), exemestane (1.5%), anastrazole (1.5%) and megestrol (1.5%).

At the data cut-off point, 18 patients are still on-treatment with palbociclib. The average duration of treatment is 5.7 months [range 2m- 17m]. The mean age of the patients was 66.3 years [range 34.8y – 85.9y] at the time of inclusion. Patients had had an average of 5.7 lines of systemic therapy [range 4 – 11 lines] before starting palbociclib, which was in 61.8% at least one line of chemotherapy. In this highly pretreated setting, 29 patients experienced stable disease lasting ≥ 6 months, resulting in an overall clinical benefit rate of 42.6%. 19.1% (13/68) showed stable disease for ≥ 9 months and 8% for ≥ 12 months. The subjective tolerance of the combination treatment was good, with 38% (26/68) of the patients discontinuing or delaying treatment following adverse events which were in the vast majority hematologic but asymptomatic. No factors predicting clinical benefit could be identified: use of chemotherapy before starting Palbociclib (p = 0.4644), age (p = 0.7029), time between primary breast cancer diagnosis and starting palbociclib (p = 0.1919) or time between first metastasis and starting palbociclib (p = 0.1108) and bone-only disease (p = 1,0000) were not significantly associated with clinical benefit at 6 months.

These data not only support the findings of the PALOMA studies, but also show unexpectedly high clinical benefit and safety of palbociclib in heavily pretreated endocrine-resistant hormone receptor positive HER-2 negative advanced breast cancer.

An update of these data will be presented.

Citation Format: Hoste G, Punie K, Wildiers H, Neven P, Berteloot P, Van Nieuwenhuysen E, Han S, Concin N, Salihi R, Lefever I, Vergote I. Palbociclib in highly pretreated metastatic ER-positive HER-2 negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-22.

Abstract P5-14-06: The effect of adjuvant chemotherapy in a large consecutive series of ER-pos HER-2 negative early breast cancers

Background: The last EBCTCG-overview reported, in general, a significant better breast cancer outcome if adjuvant chemotherapy was added to surgery and endocrine therapy in ER-pos breast cancers, but the precise indication for adjuvant chemotherapy in this population remains controversial. We study the effect of adjuvant chemotherapy on breast cancer outcome in consecutive patients with an ER-pos HER-2 negative breast cancer treated with adjuvant antihormonal therapy.

Methods: Data were collected prospectively from consecutive patients with non-metastatic breast cancer that were primary operated between 2000 and 2012 at the University Hospitals Leuven (Belgium). A Propensity Score (PS) weighted analysis was performed to estimate the average treatment effect (ATE). The primary endpoint was recurrence free interval (RFI). Secondary endpoints were distant recurrence free interval (D-RFI) and breast cancer specific survival (BCSS). Covariates used to generate the propensity score and to include in the PS weighted analysis were age at diagnosis, body mass index, tumor size, grade, pN, lymph vessel invasion, PR, and radiotherapy. Cause-specific hazard models were fitted, using death not from breast cancer as competing risk. Treatment heterogeneity was examined by evaluating interactions of each covariate with adjuvant chemotherapy, using the Bonferroni-Holm method to correct for multiple testing.

Results: In the total cohort of 5609 patients, 4282 had a hormone sensitive HER-2 neg breast cancer and 4121 (96.2%) of these received adjuvant antihormonal therapy. Adjuvant chemotherapy was given in 1179/4121 patients (29%). Median follow-up was 8.5 years. Due to very strong differences between patients with and without adjuvant chemotherapy, a restricted PS weighted analysis was used according to a recent recommendation in the statistical literature. This analysis is based on 1750 patients with a PS between 0.1 and 0.9. In this group, 807 (46%) received adjuvant chemotherapy, 211 (12%) observed an event for RFI, 167 (10%) for D-RFI, and 108 (6%) for BCSS. Adjuvant chemotherapy was associated with better prognosis: the adjusted cumulative incidence of recurrence within 5 years was 9.7% without and 5.3% with adjuvant chemotherapy. The adjusted hazard ratio for RFI was 0.50 (95% CI 0.33-0.74). There were no strong interactions with adjuvant chemotherapy. Results for D-RFI and BCSS were similar.

Conclusion: Based on PS analysis to reduce confounding and chemotherapy indication bias, we observed clear benefit from adjuvant chemotherapy in ER-pos HER-2 negative breast cancers.

Citation Format: Van Calster B, Neven P, Wildiers H, Punie K, Jongen L, Han S, Berteloot P, Van Nieuwenhuysen E, Nevelsteen I, Smeets A, Floris G. The effect of adjuvant chemotherapy in a large consecutive series of ER-pos HER-2 negative early breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-14-06.

Abstract P6-09-32: The association of breast cancer subtype and breast cancer survival with parity and time since last birth

Background: Pregnancy affects breast cancer risk but it's influence on breast cancer subtype and prognosis remains controversial. We studied the effect of parity and time since last birth on breast cancer subtype and outcome in women aged ≤50 years at diagnosis.

Patients and Methods: A retrospective multivariate cohort study including all premenopausal women aged ≤50 years (N=1306) at diagnosis and primarily treated with surgery (N=1176) or neo-adjuvant chemotherapy (N=130) at University Hospitals Leuven (Jan. 2000 – Dec. 2009); local and systemic therapies were consistent with guidelines when treated. Tumor subtypes were defined by tumor grade and receptor expression for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) amplification; ER+PR+/-HER-2- cases were Luminal A- like if grade 1-2 and Luminal B like if grade 3; HER-2+ cases were Luminal HER-2 if ER+ and HER-2 like if ER-; triple negative breast cancer (TNBC) were ER-PR-HER-2-. Outcome endpoints were breast cancer subtype, disease free (DFS) and distant disease free survival (DDFS) by parity and in parous women comparing short (&lt;5 years) versus long (≥5 years) time since last birth. Statistics used were Cox proportional hazard model. Results were corrected for age at diagnosis, tumor size, lymph node status and tumor subtype.

Results: Breast cancer subtypes didn't differ between nulliparous and parous women but subtypes differed significantly in parous women by time interval since last birth (p&lt;0.001). Breast cancers within 5 years of last birth were proportionally more likely TNBC and HER-2 like compared to Luminal A (p=0.026 and p=0.003 respectively) than breast cancers ≥5 years after last birth even when corrected for age at diagnosis. After a mean follow-up period of 10 years, parous women had a better DFS compared to nulliparous women (DFS: HR 0.754; CI 0.593-0.959; p=0.021) but after correction for known prognostic factors, only a trend remained (HR 0.783; CI 0.611-1.004; p=0.054). In parous women, those with a longer time interval since last birth had a better DFS than women with a recent pregnancy (HR 0.965; CI 0.948-0.982; p&lt;0.001). However, after correction for known prognostic factors, this association was completely attenuated (HR 0.997; CI 0.972-1.023; p=0.828). Comparable results were seen for DDFS.

Conclusion: After correction for age at diagnosis, parity does not but recent birth does affect breast cancer subtype. Such tumors are proportionally more likely ER-negative namely TNBC and HER-2 like. We observed a trend for better DFS for parous women. The prognostic value of time since last birth is mostly due to tumor characteristics and age at time of diagnosis.

Citation Format: De Mulder H, Laenen A, Wildiers H, Punie K, Poppe A, Remmerie C, Nevelsteen I, Smeets A, Van Nieuwenhuysen E, Van Limbergen E, Floris G, Vergote I, Neven P. The association of breast cancer subtype and breast cancer survival with parity and time since last birth [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-32.

P5-14-24: The Long Term Prognostic Impact of Real-Time Quantitative RT-PCR Detection of Cytokeratin 19 mRNA in Preoperative Bone Marrow Aspirates of Early Breast Cancer Patients

Purpose: Several studies have evaluated the prognostic effect of bone marrow micrometastases at the time of surgery in early breast cancer, but few studies have long term outcome data. We report here a cohort with more than ten years follow-up.

Materials and methods: 131 patients with primary operable invasive breast cancer were enrolled in the protocol from February 1998 to September 1999. Bone marrow aspirates, obtained from the iliac crest or the sternum, were analyzed with real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) for the presence of cytokeratin 19 (CK19) mRNA. All patients received standard therapy and follow-up. After a median follow-up of 133 months, data about disease recurrence (invasive disease free survival, IDFS) and survival (breast cancer specific survival (BCSS) and overall survival (OS)) were collected. A control group consisted of archived cDNA samples from 38 patients with hematological malignant antecedents in complete remission and without known gene arrangements. The upper limit of the 95% confidence interval of the level of CK19 positive cells is this group was used as cut-off (260 cytokeratin 19+ cells / 5 × 106 leucocytes) to determine bone marrow status in breast cancer patients.

Results: 69 bone marrow samples from breast cancer patients (52,7 %) were considered CK19 positive. IDFS was 60.9 % and 79 % for CK19+ and CK19- patients, respectively (log-rank p-value = 0,036). When CK19 was evaluated as a continuous variable, IDFS also correlated significantly with the level of CK19 mRNA in bone marrow aspirates (p-value = 0,019). Except for lymph node status (ANOVA linear regression p-value = 0.022), there was no significant correlation between the level of CK19+ cells in the bone marrow and classical prognostic factors (pathological tumor stage, tumor size, differentiation grade, hormonal receptor status).

In multivariate Cox-regression analysis correcting for tumor size, differentiation grade, lymph node status, hormone receptor status, tumor stage and treatment modalities (surgical procedure, chemotherapy, radiotherapy and antihormonal therapy), the CK19 bone marrow status still was a significant predictor of IDFS. (p-value = 0.042)

Differences in BCSS (78 % of CK19 + patients and 84 % of CK19 — patients) and OS (75 % in CK 19 + patients and 74 % in CK 19 — patients) were not statistically significant. (log rank p-values 0.087 and 0.883, respectively).

Conclusion: This study demonstrates the long term (&gt;ten years) prognostic effect of CK19 mRNA detection with RT-PCR in the bone marrow of operable breast cancer patients.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-24.