Patterns of Care and Clinical Outcomes of HER2-positive Metastatic Breast Cancer Patients With Newly Diagnosed Stage IV or Recurrent Disease Undergoing First-line Trastuzumab-based Therapy: A Multicenter Retrospective Cohort Study

Characteristics and prognosis of patients with primary metastatic disease vs. recurrent HER2-negative, hormone receptor-positive advanced breast cancer

BACKGROUND

Patients with first-line metastatic breast cancer (MBC) comprise patients with de novo metastases (dnMBC) or recurrent disease after primary breast cancer (rMBC). This analysis aimed to explore the prognostic value of dnMBC versus rMBC overall and particularly in subgroups according to age and metastasis site, in addition to other prognostic clinicopathological parameters in a first-line, hormone receptor (HR)-positive, HER2-negative (HRpos/HER2neg) population.

METHODS

Within the prospective PRAEGNANT MBC registry (NCT02338167), 508 HRpos/HER2neg patients, receiving first-line treatment for advanced disease, were identified. Clinicopathological parameters (age, body mass index, performance status, tumor grading, metastasis site and therapy) were assessed according to metastatic status (dnMBC, rMBC within 5 years of primary diagnosis (rMBC <5 years), rMBC after more than 5 years (rMBC ≥5 years)). Cox regression analyses were performed to investigate whether metastatic status influences progression-free survival (PFS) and overall survival (OS).

RESULTS

De novo metastatic disease was present in 180 patients (35.4 %), whereas 132 patients (26.0 %) had rMBC <5 years and 196 patients (38.6 %) had rMBC ≥5 years. Patients with dnMBC had the most favorable prognosis. Relative to dnMBC, hazard ratios for PFS were 1.75 (95%CI: 1.31-2.34) in rMBC<5 years and 1.25 (95%CI: 0.94-1.65) for rMBC ≥5 years. Subgroup-specific differences were not observed.

CONCLUSION

HRpos/HER2neg first-line MBC patients have a more favorable prognosis if the disease was previously not treated. This difference was similar across all examined clinicopathological parameters. It may therefore be beneficial to incorporate MBC categories as a stratification factor in clinical trials.

Time trends in real-world treatment patterns and survival in patients diagnosed with de novo HER2+ metastatic breast cancer: an analysis of the SONABRE registry

PURPOSE

The aim was to determine whether the real-world first-line progression-free survival (PFS) of patients diagnosed with de novo human epidermal growth factor receptor 2 positive (HER2+) advanced breast cancer (ABC) has improved since the introduction of pertuzumab in 2013. In addition to PFS, we aimed to determine differences in overall survival (OS) and the use of systemic and locoregional therapies.

METHODS

Included were patients systemically treated for de novo HER2+ ABC in ten hospitals in 2008-2017 from the SONABRE Registry (NCT-03577197). First-line PFS and OS in 2013-2017 versus 2008-2012 was determined using Kaplan-Meier analyses and multivariable Cox proportional hazards modelling. First-given systemic therapy and the use of locoregional therapy within the first year following diagnosis were determined per period of diagnosis.

RESULTS

Median and five-year PFS were 26.6 months and 24% in 2013-2017 (n = 85) versus 14.5 months and 10% in 2008-2012 (n = 81) (adjusted HR = 0.65, 95%CI:0.45-0.94). Median and five-year OS were 61.2 months and 51% in 2013-2017 versus 26.1 months and 28% in 2008-2012 (adjusted HR = 0.55, 95%CI:0.37-0.81). Of patients diagnosed in 2013-2017 versus 2008-2012, 84% versus 60% received HER2-targeted therapy and 59% versus 0% pertuzumab-based therapy as first-given therapy. Respectively, 27% and 23% of patients underwent locoregional breast surgery, and 6% and 7% surgery of a metastatic site during the first year following diagnosis.

CONCLUSION

The prognosis of patients with de novo HER2 + ABC has improved considerably. Since 2013 one in four patients were alive and free from progression on first-given therapy for at least five years.

Clinical outcomes of de novo metastatic HER2-positive inflammatory breast cancer

Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer that presents as de novo metastatic disease in 20-30% of cases, with one-third of cases demonstrating HER2-positivity. There has been limited investigation into locoregional therapy utilization following HER2-directed systemic therapy for these patients, and their locoregional progression or recurrence (LRPR) and survival outcomes. Patients with de novo HER2-positive metastatic IBC (mIBC) were identified from an IRB-approved IBC registry at Dana-Farber Cancer Institute. Clinical, pathology, and treatment data were abstracted. Rates of LRPR, progression-free survival (PFS), overall survival (OS), and pathologic complete response (pCR) were determined. Seventy-eight patients diagnosed between 1998 and 2019 were identified. First-line systemic therapy comprised chemotherapy for most patients (97.4%) and HER2-directed therapy for all patients (trastuzumab [47.4%]; trastuzumab+pertuzumab [51.3%]; or trastuzumab emtansine [1.3%]). At a median follow-up of 2.7 years, the median PFS was 1.0 year, and the median OS was 4.6 years. The 1- and 2-year cumulative incidence of LRPR was 20.7% and 29.0%, respectively. Mastectomy was performed after systemic therapy in 41/78 patients (52.6%); 10 had a pCR (24.4%) and all were alive at last follow-up (1.3-8.9 years after surgery). Among 56 patients who were alive and LRPR-free at one year, 10 developed LRPR (surgery group = 1; no-surgery group = 9). In conclusion, patients with de novo HER2-positive mIBC who undergo surgery have favorable outcomes. More than half of patients received systemic and local therapy with good locoregional control and prolonged survival, suggesting a potential role for local therapy.

Comparison between de novo and metachronous metastatic breast cancer: the presence of a primary tumour is not the only difference-a Dutch population-based study from 2008 to 2018

PURPOSE

The aim of this study was to compare characteristics and survival of patients with de novo and metachronous metastatic breast cancer.

METHODS

Data of patients with metastatic breast cancer were obtained from the Netherlands Cancer Registry. Patients were categorized as having de novo metastatic breast cancer (n = 8656) if they had distant metastases at initial presentation, or metachronous metastatic disease (n = 2374) in case they developed metastases within 5 or 10 years after initial breast cancer diagnosis. Clinicopathological characteristics and treatments of these two groups were compared, after which multiple imputation was performed to account for missing data. Overall survival was compared for patients treated with systemic therapy in the metastatic setting, using Kaplan Meier curves and multivariable Cox proportional hazards models. The hazard ratio for overall survival of de novo versus metachronous metastases was assessed accounting for time-varying effects.

RESULTS

Compared to metachronous patients, patients with de novo metastatic breast cancer were more likely to be ≥ 70 years, to have invasive lobular carcinoma, clinical T3 or T4 tumours, loco-regional lymph node metastases, HER2 positivity, bone only disease and to have received systemic therapy in the metastatic setting. They were less likely to have triple negative tumours and liver or brain metastases. Patients with de novo metastases survived longer (median 34.7 months) than patients with metachronous metastases (median 24.3 months) and the hazard ratio (0.75) varied over time.

CONCLUSIONS

Differences in clinicopathological characteristics and survival between de novo and metachronous metastatic breast cancer highlight that these are distinct patients groups.

Does definitive local therapy have a role in select HER2+ de novo metastatic breast cancer patients treated with dual anti-HER2 blockade?

PURPOSE

The role of surgery with curative intent in HER2+ de novo metastatic breast cancer (dnMBC) is uncertain in the era of dual antibody therapy. We sought to determine from existing retrospective data current practice patterns and if an association exists between surgery to the primary tumor and improved survival in HER2+ dnMBC patients treated with dual anti-HER2 blockade, accounting for selection bias.

METHODS

This study employed data from the National Cancer Database (NCDB) from the years 2013 to 2015. Study inclusion was limited to adult women with HER2+ dnMBC, who received immunotherapy/biologic response modifier drugs (BRM) as a first line treatment. Patients who received both systemic therapy and surgery to the primary breast tumor and patients who received systemic therapy alone were analyzed in two groups. Chi-square test for discrete variables and Wilcox on Rank-Sum test for numeric variables was used to compare the two groups based on patient, tumor, and treatment characteristics. The primary endpoint was overall survival from the time of diagnosis to the time of death.

RESULTS

928 women with HER2+ dnMBC treated with BRM were identified with 43.5% (n = 404) receiving surgery and 56.5% (n = 524) receiving systemic therapy alone. The 3-year overall survival was superior for the surgery group (74.1%, 95% CI 67.9-79.2%) compared to the no surgery group (53.3%; 95% CI 47.6-58.6%). The no surgery group had median overall survival of 39.8 months (95% CI 34.1-44.9), while the surgery group had not yet reached median overall survival.

CONCLUSION

In a group of HER2+ dnMBC patients receiving systemic treatment in the era of dual antibody therapy, patients who underwent surgery had a superior 3-year survival rate than those who did not. There may be a role for a prospective trial in HER2+ dnMBC patients with an excellent response to dual HER2 blockade to investigate the contribution of curative intent local therapy to the primary tumor compared to systemic therapy alone.

Prognostic Factors in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative (HR+/HER2-) Advanced Breast Cancer: A Systematic Literature Review

PURPOSE

Advanced breast cancer is a heterogeneous disease with several well-defined subtypes, among which, hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) is most prevalent. Determination of HR and HER2 status influences prognosis and, thus, disease management. Although literature on these prognostic factors exist, especially in the early breast cancer setting, it remains unclear to what extent these factors can guide clinical decision-making in the advanced disease setting. Therefore, we sought to identify the strength and consistency of evidence for prognostic factors in patients with HR+/HER2- advanced breast cancer.

METHODS

A systematic literature review (SLR) of the major electronic databases was conducted in November 2018 for primary research studies published since 2010. Endpoints of interest were tumor response, progression-free survival (PFS), overall survival (OS), and breast cancer-specific survival (BCSS).

RESULTS

Seventy-nine studies were included wherein all patients were diagnosed with advanced breast cancer and ≥50% of the population were HR+/HER2-. OS was the most commonly assessed endpoint (n=67) followed by PFS (n=33), BCSS (n=5) and tumor response (n=3). The prognostic factors with strongest evidence of association with worse OS were negative progesterone receptor status, higher tumor grade, higher circulating tumor cell (CTC) count and higher Ki67 level, number of metastatic sites (eg multiple vs single) and sites of metastases (eg presence of liver metastases vs absence), shorter time to recurrence or progression to advanced breast cancer, poor performance status, prior therapy attributes in the early or metastatic setting (type of therapy, treatment line, response of prior therapy), and race (black vs white). The prognostic factors that had strongest evidence of association with PFS included CTC count, number and sites of metastases, and absence of prior therapy or higher lines of therapy in the early or metastatic setting. The directionality of association was consistent for all prognostic factors except between lymph node and OS, and de novo metastatic breast cancer and PFS.

CONCLUSION

Multiple disease, treatment, and patient-related prognostic factors impact survival, particularly OS, in patients with HR+/HER2- advanced breast cancer. Treatment outcomes can vary considerably due to these factors. Understanding poorer prognostic factors for patients can result in improved clinical decision-making.

Can Women With HER2-Positive Metastatic Breast Cancer Be Cured?

Breast cancer that is characterized by amplification or over expression of human epidermal growth factor receptor 2 (HER2) accounts for 15% to 20% of all forms of the disease. Although HER2 amplification has been associated with aggressive disease behavior and poor prognosis, the development and availability of a number of HER2-targeted agents has led to improved outcomes for patients with HER2-positive metastatic breast cancer, with data suggesting that overall survival has substantially improved in the past 2 decades. An increasing proportion of HER2-positive metastatic breast cancer is diagnosed as de novo stage IV disease. Patients with de novo metastases are traditionally classified in the general category of metastatic breast cancer and not analyzed as a distinct subgroup, though response to therapy and disease outcomes may differ from that of disease that recurred after early stage disease. Among patients with HER2+ de novo metastatic breast cancer, those who achieve a complete response have a prolonged progression-free survival and overall survival. Moreover, the fact that some patients achieve a prolonged durable response has raised interest and renewed discussion about whether cure is feasible in the complex context of metastatic breast cancer. In this review, available data associated with the possibility of cure in the population of patients with HER2+ de novo metastatic breast cancer are presented and discussed in detail.

Utilizing Data Visualization to Identify Survival and Treatment Differences Between Women With De Novo and Recurrent Metastatic Breast Cancer

INTRODUCTION

De novo stage IV metastatic breast cancer (MBC) and recurrent MBC are considered the same when determining guideline-based care, but differences in treatment patterns exist. Data visualization can be used to understand these differences and optimize treatment delivery.

PATIENTS AND METHODS

This retrospective study evaluated treatment patterns for de novo and recurrent MBC using the American Society of Clinical Oncology's CancerLinQ Discovery database. Spatiotemporal graphics depicting treatment data were generated for MBC subtype and stratified by de novo and recurrent MBC. Descriptive statistics for categorical and continuous variables were calculated.

RESULTS

We identified 1668 patients diagnosed and treated for MBC: 391 patients with HER2+ MBC, 767 patients with HR+/HER2- MBC, and 510 patients with triple-negative MBC. Median survival from MBC diagnosis for patients with de novo MBC and recurrent MBC was 1.4 years (interquartile range, 0.6-3.0) and 1.8 years (interquartile range, 0.7-4.5), respectively. Both patients with de novo and recurrent HER2+ MBC were often treated with continuous HER2-targeted therapy. Patients with de novo HR+/HER2- MBC often received chemotherapy followed by hormone therapy. This contrasted with treatment trends observed among patients with recurrent HR+/HER2- MBC who, after receiving chemotherapy, seldom went on to receive hormone therapy. Patients diagnosed with triple-negative MBC displayed less heterogeneous treatment trends.

CONCLUSION

There are observable differences in survival and practice patterns between de novo and recurrent MBC. Visualization techniques are effective in assessing large databases and could give researchers and clinicians a clearer understanding of how survival differs by disease subtype, diagnosis status, and practice patterns.

Epidemiology of De Novo Metastatic Breast Cancer

Most cases of metastatic breast cancer (MBC) arise as a recurrence of a previously treated early breast cancer. Distinct from recurrent MBC is de novo MBC (dnMBC), which describes patients who present with distant sites of disease at initial diagnosis and is reviewed here. dnMBC represents approximately 3% to 6% of new breast cancer diagnoses in high-income countries. This incidence has not declined despite decades of widespread use of population-based mammography screening. Overrepresentation of both biologically aggressive tumors and patients negatively impacted by social determinants of health are characteristics of dnMBC. Survival has generally been superior for patients with dnMBC compared with those with recurrent MBC, although it is similar to that for patients with recurrent MBC with long disease-free intervals. Subgroups of patients with dnMBC who experience prolonged survival include those with human epidermal growth factor receptor-2-positive disease or hormone receptor-positive bone-only disease. Opportunities to decrease dnMBC presentation may include novel screening modalities suited for biologically aggressive breast tumors and improved access to health care. Recognizing that there will remain some women diagnosed with dnMBC, refining our ability to identify those likely to be long-term survivors could allow for appropriate escalation or de-escalation of care. Finally, evaluation of tumor genomics in robust sample sizes has the potential to advance our knowledge of the biology of dnMBC as an entity distinct from recurrent MBC.

The Exceptional Responders Initiative: Feasibility of a National Cancer Institute Pilot Study

BACKGROUND

Tumor molecular profiling from patients experiencing exceptional responses to systemic therapy may provide insights into cancer biology and improve treatment tailoring. This pilot study evaluates the feasibility of identifying exceptional responders retrospectively, obtaining pre-exceptional response treatment tumor tissues, and analyzing them with state-of-the-art molecular analysis tools to identify potential molecular explanations for responses.

METHODS

Exceptional response was defined as partial (PR) or complete (CR) response to a systemic treatment with population PR or CR rate less than 10% or an unusually long response (eg, duration >3 times published median). Cases proposed by patients' clinicians were reviewed by clinical and translational experts. Tumor and normal tissue (if possible) were profiled with whole exome sequencing and, if possible, targeted deep sequencing, RNA sequencing, methylation arrays, and immunohistochemistry. Potential germline mutations were tracked for relevance to disease.

RESULTS

Cases reflected a variety of tumors and standard and investigational treatments. Of 520 cases, 476 (91.5%) were accepted for further review, and 222 of 476 (46.6%) proposed cases met requirements as exceptional responders. Clinical data were obtained from 168 of 222 cases (75.7%). Tumor was provided from 130 of 168 cases (77.4%). Of 117 of the 130 (90.0%) cases with sufficient nucleic acids, 109 (93.2%) were successfully analyzed; 6 patients had potentially actionable germline mutations.

CONCLUSION

Exceptional responses occur with standard and investigational treatment. Retrospective identification of exceptional responders, accessioning, and sequencing of pretreatment archived tissue is feasible. Data from molecular analyses of tumors, particularly when combining results from patients who received similar treatments, may elucidate molecular bases for exceptional responses.

Is there a role for locoregional treatment of the primary tumor in de novo metastatic breast cancer in the era of tailored therapies?: Evidences, unresolved questions and a practical algorithm

Improvements in systemic therapies have changed the face of de novo metastatic breast cancer (dnMBC), with a 5-year survival rate exceeding 25 %. Increasing evidence suggests that a subset of patients could benefit from a locoregional treatment (LRT) with prolonged survival, although the diversity of publications on the subject make it difficult to draw any conclusions. In this review, we summarize the available data on retrospective, prospective and current ongoing clinical trials. Since factors such as tumor biology, pattern of metastatic dissemination and the timing of the treatment are closely linked to the therapeutic strategy, we focus on papers which include these aspects. We discuss recent studies indicating that exclusive radiotherapy provides results comparable with those obtained by surgery. We will then discuss the biological rationale for LRT. Finally, we propose a decision-tree to select the optimal candidates for LRT in dnMBC patients.

Incorporation of biologic factors for the staging of de novo stage IV breast cancer

This study aimed to investigate the prognostic value of biological factors, including histological grade, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status in de novo stage IV breast cancer. Based on eligibility, patient data deposited between 2010 and 2014 were collected from the surveillance, epidemiology, and end results database. The receiver operating characteristics curve, Kaplan-Meier analysis, and Cox proportional hazard analysis were used for analysis. We included 8725 patients with a median 3-year breast cancer-specific survival (BCSS) of 52.6%. Higher histologic grade, HER2-negative, ER-negative, and PR-negative disease were significantly associated with lower BCSS in the multivariate prognostic analysis. A risk score staging system separated patients into four risk groups. The risk score was assigned according to a point system: 1 point for grade 3, 1 point if hormone receptor-negative, and 1 point if HER2-negative. The 3-year BCSS was 76.3%, 64.5%, 48.5%, and 23.7% in patients with 0, 1, 2, and 3 points, respectively, with a median BCSS of 72, 52, 35, and 16 months, respectively (P < 0.001). The multivariate prognostic analysis showed that the risk score staging system was an independent prognostic factor associated with BCSS. Patients with a higher risk score had a lower BCSS. Sensitivity analyses replicated similar findings after stratification according to tumor stage, nodal stage, the sites of distant metastasis, and the number of distant metastasis. In conclusion, our risk score staging system shows promise for the prognostic stratification of de novo stage IV breast cancer.

Clinical outcomes of patients with breast cancer relapsing after (neo)adjuvant trastuzumab and receiving trastuzumab rechallenge or lapatinib-based therapy: a multicentre retrospective cohort study

Background

In the prepertuzumab era, we evaluated the clinical outcomes of patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer who underwent first-line trastuzumab-based or lapatinib-based therapy according to prior exposure to (neo)adjuvant trastuzumab.

Materials and methods

In this multicentre retrospective cohort study conducted in 14 Italian centres of the Gruppo Italiano Mammella, consecutive patients undergoing first-line trastuzumab or lapatinib-based therapy were included. Analyses were performed according to the type of first-line therapy for metastatic disease (trastuzumab or lapatinib). Dichotomous clinical outcomes were analysed using logistic regression and time-to-event outcomes using Cox proportional hazard models controlling for relevant demographic, clinicopathological and therapy characteristics.

Results

Out of 450 patients included in the study, 416 (92%) received trastuzumab and 34 (7.5%) lapatinib. As compared with the trastuzumab cohort, more patients in the lapatinib cohort had a trastuzumab-free interval <1 month (37% vs 13.9%; p=0.017) and brain metastasis as first site of relapse (38.2% vs 9.4%; p<0.001). Among the 128 patients who relapsed after prior (neo)adjuvant trastuzumab, 101 (78.9%) received first-line trastuzumab and 27 (21.1%) first-line lapatinib. The following outcomes were observed with first-line lapatinib or trastuzumab, respectively: overall response rate 45.5% vs 61.3% (p=0.184), clinical benefit rate 68.2% vs 72.5% (p=0.691), median progression-free survival (PFS) 11.4 vs 12.0 months (p=0.814) and median overall survival (OS) 34.7 vs 48.2 months (p=0.722). In patients with brain metastasis as first site of relapse, median PFS was 12.2 vs 9.9 months (p=0.093) and median OS 33.7 vs 28.5 months (p=0.280), respectively.

Conclusions

In patients with HER2-positive breast cancer relapsing after prior (neo)adjuvant trastuzumab, first-line treatment with trastuzumab or lapatinib was not associated with a significant difference in the clinical outcomes. A non-significant trend favouring the use of lapatinib was observed in patients with brain metastasis as the first site of relapse.

Impact of age at diagnosis of metastatic breast cancer on overall survival in the real-life ESME metastatic breast cancer cohort

BACKGROUND

Young age is a poor prognostic factor in early stage breast cancer (BC) but its value is less established in metastatic BC (MBC). We evaluated the impact of age at MBC diagnosis on overall survival (OS) across three age groups (<40, 40 to 60 and > 60 years(y)).

METHODS

ESME MBC database is a national cohort, collecting retrospective data from 18 participating French cancer centers between January 01, 2008 and December 31, 2014.

RESULTS

Among 14 403 women included, 1077 (7.5%), 6436 (44.7%) and 6890 (47.8%) pts were <40, 40-60 and > 60 y respectively. Pts <40 had significantly more aggressive presentations than other age groups: more frequent HER2+ (25.7 vs 15.3% in >60y) and triple negative subtypes (27.4 vs 14.6% in >60y), and more frequent visceral involvement (36.3 vs 29.8% in >60y). At a median follow-up of 48 months, median OS differed across age groups: 38.8, 38.4 and 35.6 months for pts <40, 40-60 and > 60y, respectively (p < 0.0001). Compared to pts <40y, older pts had a statistically significant higher risk of death (all causes of death included), although of limited clinical value (HR = 1.1, IC 95%:1.01-1.20). There was a significant trend for better OS in pts <40y with HER2+ and luminal diseases. A possible explanation is a greater use of anti-Her2 therapies as first-line treatments: 86.6, 81.9 and 74.9% for pts <40, 40-60 and > 60y, respectively (p < 0.0001).

CONCLUSION

Although young age seems associated with more aggressive presentations at diagnosis of MBC, it has no deleterious effect on OS in this large series.

De novo metastatic breast cancer: Subgroup analysis of molecular subtypes and prognosis

The purpose of the present study was to analyze the clinical and pathological characteristics, treatment, and prognosis of de novo metastatic breast cancer (DnMBC). Information regarding 1,890 patients treated for advanced breast cancer at the Tianjin Medical University Cancer Hospital between January 2008 to December 2017 was collected. Clinicopathological characteristics, treatments and outcomes of these patients were compared using the chi-square test, log-rank test, and Cox regression analysis. A total of 171 patients were diagnosed with DnMBC. The median age at diagnosis was 53 years (range, 23–77). The percentage of T4 staging was higher (37.4%), 69.6% of patients were estrogen receptor (ER) positive, 59.1% were progesterone receptor positive, 29.8% had positive human epidermal growth factor receptor 2 (HER2) status, 68.4% had Ki-67 ≥20%, 55% had oligometastasis at the initial diagnosis, ~87.7% were treated with chemotherapy initially and 24% received palliative surgery for the primary tumor. After a median follow-up time of 26 months, the median progression-free survival (PFS) and overall survival (OS) among patients with DnMBC were 11 (8.7–13.3) months and 34 (27.9–40.1) months, respectively. In the multivariable model, ER status and sites of first metastasis (oligometastasis or polymetastasis) were identified to be independent predictors of PFS (P<0.05); ER status, primary tumor stage, and surgical treatment of primary tumors were identified to be independent predictors of OS (P<0.05). In conclusion, the clinicopathological characteristics of DnMBC are greater invasiveness and a higher risk of progression. Palliative surgical treatment may improve the prognosis of HR+/HER2-patients with oligometastasis. Therefore, individualized treatment as required is particularly important.

Locoregional therapy of the primary tumour in de novo stage IV breast cancer in 216 066 patients: A meta-analysis

Patients presenting with de novo stage IV metastatic breast cancer have a complex disease which is normally treated with palliative intent and systemic therapy. However, there is mounting evidence that resection of the primary tumour and/or localised radiotherapy (locoregional therapy; LRT) could be associated with overall survival improvements. We aimed to conduct a meta-analysis to inform decision making. Using the PubMed, Cochrane and Ovid SP databases, a literature review and meta-analysis were conducted to assess the effect of LRT on overall survival. Studies were analysed for the impact of LRT on survival. All forms of LRT resulted in a significant 31.8% reduction in mortality (N = 42; HR = 0.6823 (95% CI 0.6365; 0.7314)). Surgical resection resulted in a significant 36.2% reduction in mortality (N = 37; HR = 0.6379 (95% CI 0.5974; 0.6811)). The prospective trials reported a 19.23% reduction in mortality which was not statistically significant (N = 3, HR = 0.8077 (95% CI 0.5704; 1.1438). 216 066 patients were included. This is the largest meta-analysis regarding this question to date. Our meta-analysis shows that LRT of the primary tumour seems to improve overall survival in de novo stage IV disease. Therefore, this therapeutic option should be considered in selected patients after a careful multidisciplinary discussion.

Pertuzumab and Trastuzumab Emtansine for Human Epidermal Growth Factor Receptor-2-Positive Metastatic Breast Cancer: Contemporary Population-Based Outcomes

Background

Real-world outcomes for patients with human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer (MBC) treated with pertuzumab in combination with taxane chemotherapy plus trastuzumab (TaxTP) in the first line setting and trastuzumab emtansine (TE) in any line of treatment are lacking.

Methods

Cohorts of patients treated with (1) TaxTP and (2) TE from January 1, 2013 through December 31, 2016 were retrospectively obtained from a population-based database. Cohorts were described according to age, hormone receptor (HR) status, prior systemic therapies, event-free survival (EFS) defined as time from start of treatment to start of next line of treatment or death, and overall survival (OS).

Results

A total of 122 patients were treated with TaxTP and 104 with TE. In the TaxTP cohort, EFS was significantly longer in the trastuzumab-naïve group compared with the adjuvant trastuzumab group (median EFS = 27.0 vs 12.4 months; P = .002). In the TaxTP cohort, median OS was not reached. In the TE cohort, EFS was significantly longer in the pertuzumab-naïve group compared with pertuzumab-exposed group (median time to treatment failure [TTF] = 18.7 vs 5.5 months; P < .001). Overall survival was also significantly longer in the pertuzumab-naïve group compared with the pertuzumab-exposed group (median OS = 23.2 vs 14.1 months; P = .022). In multivariable analyses, adjuvant trastuzumab and prior pertuzumab exposure in the metastatic setting remained significant predictors of inferior EFS for patients treated with TaxTP and TE, respectively.

Conclusions

New anti-HER2 therapies appear to be clinically relevant in the real-world.

Relapsed and De Novo Metastatic HER2-positive Breast Cancer Treated With Trastuzumab: Tumor Genotypes and Clinical Measures Associated With Patient Outcome

BACKGROUND

We examined tumor genotype characteristics of human epidermal growth factor receptor 2 (HER2)-positive relapsed (R-) and de novo (dn-) metastatic breast cancer (MBC) in trastuzumab-treated patients who were previously not exposed to this agent.

MATERIALS AND METHODS

We analyzed genotypes obtained upon deep sequencing from 113 HER2-positive primary tumors from 69 patients with R-MBC and 44 patients with dn-MBC.

RESULTS

Mutations were observed in 90 (79.6%) tumors, 56 R-MBC and 34 dn-MBC (median number per tumor: 2; mean: 11.2; range: 0-150). The top mutated gene was TP53 (63.7%) followed by PIK3CA (24.8%) and others that were mostly co-mutated with TP53 (eg, 22 of 28 PIK3CA mutated tumors were co-mutated in TP53, 17 of these were R-MBC [P = .041]). dn-MBC had higher CEN17 average copies (P = .048). Tumor mutational burden inversely correlated with average HER2 copies (rho -0.32; P < .001). In all patients, PIK3CA mutations and higher proliferation rate were independent unfavorable prognosticators. In R-MBC, longer disease-free interval between initial diagnosis and relapse conferred lower risk for time-to-progression (P < .001) and death (P = .009); PIK3CA mutations conferred higher risk for death (P = .035). In dn-MBC, surgical removal of the primary tumor before any other therapy was favorable for time-to-progression (P = .002); higher tumor mutational burden was unfavorable for survival (P = .026).

CONCLUSIONS

Except for the overall unfavorable prognostic effect of PIK3CA mutations in trastuzumab-treated MBC, our exploratory findings indicate that the outcome of patients with R-MBC is related to patient benefit from the preceding adjuvant chemotherapy and provide initial evidence that tumor mutational burden may be related to prognosis in dn-MBC, which is of potential clinical relevance and merits further investigation.

Patients who achieved long-term clinical complete response and subsequently terminated multidisciplinary and anti-HER2 therapy for metastatic breast cancer: A case series

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Breast cancers that are positive for human epidermal growth factor receptor 2 (HER2) are aggressive and typically associated with a poor prognosis.

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Novel anti-HER2 therapies have recently improved the outcomes in these cases.

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We report a case series in which women were treated for metastatic HER2-positive breast cancer using trastuzumab and various chemotherapies.

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These patients ultimately achieved clinical complete response, and subsequently terminated their systemic therapy after maintenance therapy.

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Our findings indicate that select patients may be suitable for treatment termination if they have achieved a prolonged period of complete response.

Background

Human epidermal growth factor receptor 2 (HER2) -positive breast cancers tend to be more aggressive and more likely to recur than HER2-negative breast cancers. However, novel anti-HER2 therapies have dramatically improved the prognosis of patients with HER2-positive breast cancer.

Case report

We review the cases of 4 women with metastatic breast cancer who achieved clinical complete response (cCR) and terminated their systemic therapy. Two patients had de novo metastatic disease and two patients experienced relapse after adjuvant therapy. All patients achieved cCR using multidisciplinary therapy, experienced prolonged complete remission, and subsequently terminated their systemic therapy without experiencing secondary recurrence.

Conclusion

There is no evidence that systemic therapy can be safely terminated after a specific time period, although adverse events (e.g., cardiotoxicity) and unnecessary treatment should be avoided. Thus, it is possible that select patients may be suitable for termination of systemic therapy after they have achieved a prolonged period of cCR.

Long-Term Survival of De Novo Stage IV Human Epidermal Growth Receptor 2 (HER2) Positive Breast Cancers Treated with HER2-Targeted Therapy

BACKGROUND

An increasing proportion of human epidermal growth receptor 2 (HER2) positive (HER2+) metastatic breast cancer (MBC) is diagnosed as de novo stage IV disease. We hypothesize that a subset of these patients who achieve no evidence of disease (NED) status after multimodality HER2-targeted treatments may have prolonged progression-free survival (PFS) and overall survival (OS).

MATERIALS AND METHODS

Patients with de novo stage IV, HER2+ MBC (n = 483) diagnosed between 1998 and 2015 were identified at two institutions (Yale and MD Anderson Cancer Centers). Clinical variables, treatment details, and survival outcomes were compared between those who achieved NED and those who did not.

RESULTS

All patients received trastuzumab, and 20% also received pertuzumab as first-line therapy. The median OS was 5.5 years (95% confidence interval [Cl]: 4.8-6.2). Sixty-three patients (13.0%) achieved NED; their PFS and OS rates were 100% and 98% (95% CI: 94.6%-100%), respectively, at 5 years and remained the same at 10 years. For patients with no NED (n = 420), the PFS and OS rates were 12% (95% CI: 4.5%-30.4%) and 45% (95% CI: 38.4%-52.0%) at 5 years and 0% and 4% (95% CI, 1.3%-13.2%) at 10 years, respectively. NED patients more frequently had solitary metastasis (79% vs. 51%, p = .005) and surgery to resect cancer (59% vs. 22%, p ≤ .001). In multivariate analysis, NED status (hazard ratio [HR]: 0.014, p = .0002) and estrogen receptor positive status (HR: 0.72; p = .04) were associated with prolonged OS.

CONCLUSION

Among patients with de novo stage IV, HER2+ MBC, those who achieve NED status have a very high PFS and OS. Further randomized studies are required to fully understand the impact of systemic or locoregional therapy on achieving these excellent long-term outcomes.

IMPLICATIONS FOR PRACTICE

In this retrospective review at two institutions, it was demonstrated that 13% of patients with de novo stage IV, human epidermal growth receptor 2 positive metastatic breast cancer achieved no evidence of disease (NED) status with trastuzumab-based therapy plus/minus local therapies, and these patients had a very high progression-free survival (100%) and overall survival (98%) at both the 5- and 10-year time points. Achieving NED status may be an important therapeutic goal. However, further randomized studies are required to fully understand the impact of systemic or locoregional therapy on achieving these excellent long-term outcomes.

Trastuzumab for metastatic breast cancer: Real world outcomes from an Australian whole-of-population cohort (2001-2016)

PURPOSE

Outcomes for patients treated in clinical trials may not reflect the experience in routine clinical care. We aim to describe the real-world treatment patterns and overall survival (OS) for women receiving trastuzumab for metastatic breast cancer (MBC).

METHODS

Retrospective, whole-of-population cohort study using demographic, dispensing, and medical services data for women in the Herceptin Program for HER2+MBC. We estimated time on trastuzumab and OS from first dispensing of trastuzumab for MBC and rates of cardiac monitoring prior to and during treatment. We stratified outcomes by two groups based on year of initiation: 2001-2008 and 2009-2015. We benchmarked outcomes to two key trastuzumab clinical trials: H0648g (median OS 25 months) and CLEOPATRA (control group median OS 41 months).

RESULTS

Median age of the 5899 women at first trastuzumab dispensing was 57 years (interquartile range [IQR]: 48-66). Median time on trastuzumab increased from 15 months (7-33) in Group One to 18 months (8-42) in Group Two. Median OS increased from 27 months (12-57) in Group One to 38 months (16-83) in Group Two. Rates of cardiac monitoring increased at baseline (52%-76%), and on-treatment (47%-67%), in Group One and Two, respectively.

CONCLUSIONS

OS, duration of trastuzumab, and frequency of cardiac monitoring increased over the study period. Outcomes for trastuzumab in this heterogeneous real world population were reassuringly comparable to those from clinical trials, with the median OS > 3 years in Group Two and 25% of patients living 7 years or longer.