Abstract PD3-11: HER2/ERBB2 status in “HER2 equivocal” breast cancers by FISH and ASCO-CAP guidelines: False-positives due to heterozygous deletions of alternative control loci

Background. The ASCO-CAP guidelines for HER2 testing by fluorescence in situ hybridization (FISH) have a category, referred to as “equivocal” (average HER2 copies per tumor cell >4-6 with HER2/CEP17 ratio <2·0), which is neither “HER2-positive” nor “HER2-negative”. Approximately 4% - 12% of invasive breast cancers are “HER2-equivocal” based on FISH. Cancers in this category may be resolved as “negative” or “positive” by FISH alternative control probes (2013/2014 guidelines) or HER2 immunohistochemistry (IHC) (2018 update). Our objectives were to evaluate the following hypotheses: 1.) Genetic loci used as alternative controls show heterozygous deletion in a substantial proportion of breast cancers; 2.) Use of these loci for assessment of HER2 by FISH leads to false-positives; 3.) HER2 FISH false-positive breast cancer patients have outcomes that do not differ from clinical outcomes for HER2-negative breast cancer patients; and 4.) HER2-equivocal breast cancers seldom show HER2 protein overexpression (IHC 3+).

Methods. We retrospectively assessed the use of chromosome 17 p-arm and q-arm alternative control genomic sites (TP53, D17S122, SMS, RARA, TOP2A), as recommended by the 2013/2014 ASCO-CAP guidelines, in patients whose data were available through the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC)(N=1980) or whose tissues were available from the BCIRG-005 clinical trial (N=3298). We used either FDA-approved HER2 IHC (HercepTest) or laboratory-developed HER2 (10H8) IHC assays to assess HER2 protein expression.

Results. Using METABRIC we found heterozygous deletions, particularly in specific p-arm sites, were common in both HER2-amplified and HER2-not-amplified breast cancers. Use of alternative control probes from these regions to assess HER2 by FISH in “HER2 equivocal” as well as HER2-not-amplified breast cancers resulted in high rates of false-positive ratios (HER2-to-alternative control ratio >2·0) due to heterozygous deletions of control p-arm genomic sites used as ratio denominators. Misclassifications of HER2 status was observed not only in breast cancers with ASCO-CAP “equivocal” status but also in breast cancers with an average of <4·0 HER2 copies per tumor cell. These deletions were also identified by FISH. IHC demonstrated <1% of FISH “HER2-equivocal” breast cancers in BCIRG-005 had IHC3+ immunostaining, consistent with HER2-not-amplified status. Clinical outcomes of “HER2-equivocal” breast cancer patients with HER2-to-alternative control ratio >2·0 did not differ significantly from clinical outcomes of those with HER2-to-alternative control ratio<2·0.

Conclusion. Using chromosome 17 p-arm alternative controls, as recommended by 2013/2014 ASCO-CAP guidelines, instead of CEP17 for resolution of “HER2 equivocal” cases, is problematic due to frequent heterozygous deletions of these loci in breast cancers. The indiscriminate use of alternative control probes to calculate a HER2 FISH ratio in “HER2-equivocal” breast cancers leads to false-positive interpretations of HER2 status resulting from unrecognized heterozygous deletions in one or more of these alternative control genomic sites and incorrect HER2 ratio determinations.

Citation Format: Press MF, Seoane JA, Curtis C, Quinaux E, Guzman R, Sauter G, Eiermann W, Mackey JR, Robert N, Pienkowski T, Crown J, Martin M, Valero V, Bee V, Ma Y, Villalobos I, Slamon DJ. HER2/ERBB2 status in “HER2 equivocal” breast cancers by FISH and ASCO-CAP guidelines: False-positives due to heterozygous deletions of alternative control loci [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 PD3-11.

A global meta-analysis of the economic values of provisioning and cultural ecosystem services

Despite a growing demand to integrate ecosystem services into sustainability decision-making, our understanding of the global distribution of the economic value of ES is scarce. We extracted information from provisioning and cultural ecosystem services (PCES) from The Economics of Ecosystems and Biodiversity (TEEB) database using a meta-analytical approach. We then employed geostatistical methods to analyze the relationship between economic values and environmental and socio-economic predictors. Here we show that anthropogenic related factors such as accessibility, spatially explicit gross domestic product and ecosystem services scarcity explain global trends of PCES economic values. We observe higher PCES values in agricultural areas of strong human presence such as the British Isles, Southwest of Brazil and India and lower values in less disturbed natural areas. These findings highlight the decisive role that human systems play in the economic realization of PCES and caution that single-criterion sustainability and conservation policies aimed at maximizing the economic returns of PCES may not overlap with wild nature.

Abstract P1-09-04: Proliferation and p21 refine risk of relapse in residual disease after HER2-directed therapies

Background: Patients (pts) with residual disease (RD) after neoadjuvant therapy are at higher risk of relapse. We investigated whether biomarkers assessed at surgery in patients pts with RD in the NeoSphere study were informative for risk of distant event free survival (DEFS)

Methods: In NeoSphere 417 HER2+ pts were randomized to neoadjuvant TD, TPD, TP or PD (T=trastuzumab, P=pertuzumab, D=docetaxel), and received FAC/FEC and trastuzumab after surgery. 296 pts had RD. Affymetrix derived gene expression profiles (GEPs) were available at surgery for 201 pts (67.9%). 176 pts (60.1%) had paired samples before and after treatment with available GEPs. We investigated the prognostic value of proliferation evaluated by Mitosis Kinase Score (MKS) (Bianchini G Cancer Res 2010), and performed a gene discovery for association between gene expression at surgery and DEFS.

Results: MKS as continuous marker was associated with significantly higher risk of relapse when assessed at surgery (HR 1.80 [1.23-2.65]; p=0.002), but not before treatment (HR 1.50 [0.80-2.78]; p=0.20). In paired samples, there was an average decrease (p=9.2E-11) of MKS after treatment, which was prominent in ER+ and chemotherapy-containing arms. In ER- and TP arm there were cases of increase and of decrease of MKS. In ER+ the 5 years DEFS was 94.3% in the Low/Int MKS tertiles group (pooled) vs 70.5% in the High MKS tertile group (HR 5.41 [1.87-15.6]; p=0.002). In ER-, the 5 years DEFS was 85.0% in the Low/Int vs 64.1% in the High group (HR 2.89 [1.08-7.76]; p=0.035). Notably, MKS at surgery after the two monoclonal alone was also prognostic.

In the gene discovery approach only the expression of CDKN1A (p21)at surgery was associated with DEFS after correction for false discovery rate (FDR=0.01). Pre-treatment p21 was not associated with DEFS. Paired comparison showed significant upregulation of p21 in all patients, treatment arms and ER groups. The Int/High p21 tertiles group (pooled) had lower risk of recurrence than the low tertile in ER+ (HR 4.31 [1.60-11.6]; p=0.004) and in ER- (HR 5.81 [1.87-18.1]; p=0.002) groups. p21 in TP arm was also prognostic. MKS and p21 expression provided independent prognostic information and remained significant after correction for clinico-pathological variables (nodes and T stage) and tumor-infiltrating lymphocytes. Combining the two markers, there was a group at very low risk (Low/Int MKS and Int/High p21) and one at high risk (High MKS and Low p21). The other tertiles combinations had intermediate risk. In ER+, the 5 yrs DEFS was 94.9% in the low risk group and 52.9% in the high risk (p=1.9E-05). In ER-, the 5 yrs DEFS was 96.5% in the low and 45.5% in the high risk group (p=0.001).The markers' combination was also prognostic in the two monoclonal only arm.

Conclusions: Proliferation (MKS) and p21 expression are modulated by trastuzumab and/or pertuzumab regimens. Tumors with high MKS and low p21 in RD after neoadjuvant therapy defined a group at very high risk of relapse. Tumors with low/int proliferation and int/high p21 had low risk of recurrence similar to that of patients achieving pCR. Whether the pharmacodynamic modulation of p21 could be used as surrogate marker of long term benefit in patients with RD deserves additional investigation.

Citation Format: Bianchini G, Pienkowski T, Im Y-H, Bianchi GV, Tseng L-M, Liu M-C, Lluch A, de la Haba-Rodríguez J, Semiglazov V, Oh D-Y, Poirier B, Pedrini JL, Valagussa P, Gianni L. Proliferation and p21 refine risk of relapse in residual disease after HER2-directed therapies [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 P1-09-04.

Abstract P6-03-09: Genetic polymorphism and correlation with treatment induced cardiotoxicity and prognosis in HER2 amplified early breast cancer patients

Introduction: Small studies have indicated a possible correlation between a HER2 gene polymorphism at codon 655 and trastuzumab-associated cardiotoxicity. Association between a synonymous coding variant rs7853758 within the SLC28A3 gene and anthracycline induced cardiotoxicity has also been reported. This study aimed to validate these correlations and assess for any relationship with prognosis.

Methods: Genomic DNA was isolated from 666 patients enrolled in a large trial of adjuvant chemotherapy in HER2 amplified early breast cancer (BCIRG 006). Genotyping was conducted using Sequenom MassARRAY System for HER2 G->A polymorphism at amino acid codon 655 (rs1136201) and variant rs7853758 (L461L) within the SLC28A3 gene.

Results: Of the 666 patients analyzed, 216 patients were treated with anthracycline based therapy, 226 with trastuzumab based therapy, and 224 with regimens containing both an anthracycline and trastuzumab. Compared with the overall results of the BCIRG006 study (N=3,222), in the subset of patients genotyped in this analysis, a less robust improvement in disease free survival (DFS) was observed for the trastuzumab arms than control arm (HR, 0.821). When stratified for prognostic features, the hazard ratio in favor of trastuzumab was consistent with that of the overall study (HR, 0.674). Samples from 662 patients were successfully genotyped for rs1136201. Of these, 424 (64%) were AA, 30 (4.5%) were GG, 208 (31%) were AG genotype. Samples from 665 patients were successfully genotyped for rs7853758. Of these, 19 (3%) were AA, 475 (71%) were GG, and 171 (26%) were AG genotype. There was no correlation seen between mean left ventricular ejection fraction (LVEF) and HER2 genotype at codon 655 in patients treated with trastuzumab. Of patients tested for the HER2 polymorphism, cardiac dysfunction [defined as > 10% decline in LVEF or clinical congestive heart failure (CHF)] developed in 16% of patients with AA, 17% of patients with GG and 20% of patients with AG. There was also no correlation between mean LVEF and variant rs7853758 in patients treated with anthracyclines. The percentage of patients who developed cardiac dysfunction was 13%, 17% and 21% in AA, GG, and AG genotypes respectively. No correlation between disease free survival and any of the genotypes was seen.

Conclusion: In the largest analysis to date to evaluate for relationship between cardiac toxicity and HER2 polymorphism, we did not find a correlation with rs1136201 HER2 polymorphism and trastuzumab induced cardiac toxicity. Our study also did not show a correlation between variant rs7853758 (L461L) and anthracycline induced cardiotoxicity. Neither polymorphism correlated with prognosis.

Citation Format: Peddi PF, Hurvitz SA, Fasching PA, Wang L, Cunningham J, Weinshilboum RM, Liu D, Quinaux E, Fourmanoir H, Robert NJ, Valero V, Crown J, Falkson C, Brufsky A, Pienkowski T, Eiermann W, Martin M, Bee V, Slamon DJ. Genetic polymorphism and correlation with treatment induced cardiotoxicity and prognosis in HER2 amplified early breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-09.

Selecting first-line bevacizumab-containing therapy for advanced breast cancer: TURANDOT risk factor analyses

BACKGROUND

The randomised phase III TURANDOT trial compared first-line bevacizumab-paclitaxel (BEV-PAC) vs bevacizumab-capecitabine (BEV-CAP) in HER2-negative locally recurrent/metastatic breast cancer (LR/mBC). The interim analysis revealed no difference in overall survival (OS; primary end point) between treatment arms; however, progression-free survival (PFS) and objective response rate were significantly superior with BEV-PAC. We sought to identify patient populations that may be most appropriately treated with one or other regimen.

METHODS

Patients with HER2-negative LR/mBC who had received no prior chemotherapy for advanced disease were randomised to either BEV-PAC (bevacizumab 10 mg kg(-1) days 1 and 15 plus paclitaxel 90 mg m(-2) days 1, 8 and 15 q4w) or BEV-CAP (bevacizumab 15 mg kg(-1) day 1 plus capecitabine 1000 mg m(-2) bid days 1-14 q3w). The study population was categorised into three cohorts: triple-negative breast cancer (TNBC), high-risk hormone receptor-positive (HR+) and low-risk HR+. High- and low-risk HR+ were defined, respectively, as having ⩾2 vs ⩽1 of the following four risk factors: disease-free interval ⩽24 months; visceral metastases; prior (neo)adjuvant anthracycline and/or taxane; and metastases in ⩾3 organs.

RESULTS

The treatment effect on OS differed between cohorts. Non-significant OS trends favoured BEV-PAC in the TNBC cohort and BEV-CAP in the low-risk HR+ cohort. In all three cohorts, there was a non-significant PFS trend favouring BEV-PAC. Grade ⩾3 adverse events were consistently less common with BEV-CAP.

CONCLUSIONS

A simple risk factor index may help in selecting bevacizumab-containing regimens, balancing outcome, safety profile and patient preference. Final OS results are expected in 2015 (ClinicalTrials.gov NCT00600340).

Abstract P6-06-40: Analysis of outcome according to risk factors in the randomized phase III TURANDOT trial evaluating first-line bevacizumab-containing therapy for HER2-negative locally recurrent/metastatic breast cancer (LR/mBC)

Background: The randomized phase III TURANDOT trial compared first-line bevacizumab (BEV) + paclitaxel (PAC) vs BEV + capecitabine (CAP) in HER2-negative LR/mBC [Lang, Lancet Oncol 2013]. At the prespecified interim analysis there was no detectable difference in overall survival (OS; primary endpoint) between treatment groups, but the secondary endpoints of progression-free survival (PFS) and objective response rate (ORR) favored BEV-PAC. We sought to identify patient populations defined by risk factors that may be most appropriately treated with one or other of the regimens.

Methods: Patients with HER2-negative LR/mBC who had received no prior chemotherapy for LR/mBC were randomized to either BEV-PAC (BEV 10 mg/kg d1 & 15 + PAC 90 mg/m2 d1, 8, & 15 q4w) or BEV-CAP (BEV 15 mg/kg d1 + CAP 1000 mg/m2 bid d1-14 q3w). The study population was categorized into three cohorts: triple-negative (TNBC), high-risk hormone receptor-positive (HR+) and low-risk HR+. High-risk and low-risk HR+ were defined, respectively, as having ≥2 vs ≤1 of the following four risk factors: disease-free interval ≤24 months; visceral metastases; prior (neo)adjuvant anthracycline and/or taxane; ≥3 metastatic sites.

Results: Baseline characteristics, efficacy, and safety by treatment arm are summarized below for the three cohorts. Although PFS results in all cohorts favored BEV-PAC, interim OS results showed a trend in favor of BEV-PAC in TNBC patients and in favor of BEV-CAP in low-risk HR+ patients. Grade ≥3 adverse events were less common with BEV-CAP than BEV-PAC in all three cohorts.

 TNBCHigh-risk HR+Low-risk HR+ BEV-PAC (n = 63)BEV-CAP (n = 67)BEV-PAC (n = 146)BEV-CAP (n = 162)BEV-PAC (n = 75)BEV-CAP (n = 50)Median age, years545658576161ECOG PS 0,%756068666366PFS      Events, n (%)50 (79)54 (81)93 (64)125 (77)33 (44)35 (70)Median, months (95% CI)9.0 (7.8-10.7)5.6 (4.9-8.0)11.1 (10.4-13.4)8.3 (7.1-10.7)14.4 (10.4-20.5)11.5 (8.1-16.3)HR (95% CI)a1.37 (0.93-2.02)1.29 (0.98-1.69)1.39 (0.86-2.25)OS      Events, n (%)28 (44)34 (51)50 (34)52 (32)18 (24)11 (22)1-year OS rate,%786380828590HR (95% CI)a1.33 (0.80-2.19)0.97 (0.66-1.43)0.80 (0.38-1.69)Grade ≥3 AEs,%634261516148aBEV-CAP vs BEV-PAC

Conclusion: The simple risk factor index is prognostic for both PFS and OS and may be used to guide treatment choice when selecting BEV-containing therapy, balancing outcome with safety profile and patient preference. Final analysis of OS is expected in 2014.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-40.

Abstract P5-02-02: Factors influencing time to seeking medical advice and start of treatment in breast cancer (BC) patients – an International survey

Background. We earlier reported patient-related factors influencing the delay in first medical advice for signs of BC in selected countries (J Clin Oncol 2012;30[15S]:578s). The present analysis, which includes additional countries, addresses the factors influencing time from first symptoms of BC to initiation of treatment (Total Delay Time; TDT).

Methods. A total of 6,588 female BC patients from 11 countries were surveyed using a uniform questionnaire translated into local languages. TDT was determined using 8 individual scales, including one pertaining to patient delay and 7 related to subsequent steps in a typical diagnostic process. Regression models were constructed using 18 variables concerning diverse contextual and personal patient characteristics. Due to expected differences in the relevant sets of predictors, time between first symptoms and first medical visit (Patient Delay Time; PDT) and time between first medical visit and start of therapy (System Delay Time; SDT) were modeled separately, with multilevel regression.

Results. Mean TDT varied in individual countries from 11.5 to 29.4 weeks (grand mean of 14.3 weeks; see table), with 43% of cases with a delay of >12 weeks. Multilevel regression equation indicated that factors significantly correlated with longer PDT were distrust in the medical system and ignoring disease. Patients with fear of the disease, stronger self-examination habits, at least secondary education, being employed, reporting more support from friends and family, and living in cities of >100,000 inhabitants had shorter PDT. Predictors of shorter SDT included being diagnosed by an oncologist vs. other physician, having at least secondary education, being older than 60 years, having a history of cancer in female relatives and having breast lump vs. other BC symptoms. Indicators of longer SDT were PDT >4 weeks, more than one BC symptom detected by patient, distrust in the medical system, disregard of BC signs, less support from friends and family, and having first medical examination in a public vs. private medical center. Individual countries differed significantly with regard to intercept of the multilevel models and slopes of regression coefficients for selected psychological and behavioral attributes.

Conclusions. An extensive set of variables potentially impacting delay times, mainly related to psychological and behavioral patient attributes, was examined. Several of them strongly determined both PDT and SDT, but their strength differed between individual countries. Both models (for PDT and SDT), although statistically significant, accounted for approximately 20% of variance in time; therefore other variables, e.g. related to the differences in national healthcare systems (not addressed in this study) might have a stronger impact on delays in the initiation of BC therapy and warrant further analyses.

Abstract P3-10-24: Fibroblast Growth Factor Receptor 1 Amplification and Overexpression in Breast Cancer Tissue Microarrays Using Chromogenic In Situ Hybridization and Immunohistochemistry

Fibroblast growth factor receptors 1 (FGFR1) belongs to a subfamily of receptor tyrosine kinases (RTKs), which are involved in proliferation and apoptosis. FGFR1 amplification and mRNA overexpression occurs in ∼10% of breast cancers and has been associated with poor outcome. However, studies assessing FGFR1 amplification and protein overexpression in a large collection of breast tumors are lacking. In this prospective, we examined a series of primary breast cancers samples derived from the BCIRG trials assembled into 15 tissue microarrays. FGFR1 gene amplification was studied using chromogenic in situ hybridization (CISH) and evaluated with respect to association with level of protein expression and clinicopathological parameters. FGFR1 gene amplification was significantly associated with high protein levels as determined by immunohistochemistry (P<0.0001, 3294 pts with available matched CISH and IHC records). Overall, the incidence of FGFR1 amplification found was 9.7% (160 out of 1646 pts. with available clinicopathological records) without a statistically significant difference between Her2- (78 out 720 pts., 11%) and Her2+ (82 out of 926 pts., 9%) cancers. In both cohorts, the hormone receptor-positive (ER+/PR+) cancers showed statistically significant higher levels of FGFR1 amplification compared to hormone receptor-negative tumors. In the analysis of the association of FGFR1 and the presence of PIK3CA mutations, the incidence of FGFR1 amplificationwas greatly reduced in mutant vs. wt PI3KCA tumors. In these cohorts, a clear relationship between FGFR1 amplification status and clinical outcome was not detected. Data from this large study confirms recently reported incidences of FGFR1 amplification in breast cancer and shows for the first time an association between FGFR1 gene amplification and protein overexpression. Moreover, the lower incidence of FGFR1 amplification in PIK3CA mutated cancers suggests that these are largely exclusive molecular events that could benefit from different targeted therapies.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-24.

ONCOPOOL - a European database for 16,944 cases of breast cancer

ONCOPOOL is a retrospectively compiled database of primary operable invasive breast cancers treated in the 1990s in 10 European breast cancer Units. Sixteen thousand and nine hundred and forty four cases were entered, with tumours less than 5 cm diameter in women aged 70 or less (mean age 55).

DATA

Data were date of birth, mode of diagnosis, pathology (size, lymph node status, grade, type, lympho-vascular invasion and hormone receptor) and therapies and outcome measures: first local, regional or distant recurrences, contralateral primary, date and cause of death.

TUMOUR CHARACTERISTICS

Mean diameter 1.8 cm, 66% lymph node negative, 24% 1-3 lymph nodes involved and 10% had 4 or more involved. Grade 1, 29%; Grade 2, 41%; and Grade 3, 30%. Polynomial relationships were established between grade, stage and size. Seventy-five percent were oestrogen receptor (ER) positive. ER closely related to grade.

OUTCOMES

Overall Survival was 89% at 5 years from diagnosis, 80% 10 years and 73% 15 years; Breast Cancer-Specific survivals were 91%, 84% and 79%. Survival strongly related to the Nottingham Prognostic Index (NPI). Cases detected at screening had 84% 10-year survival, those presenting symptomatically 76%. ER positive cases treated with adjuvant hormone therapy had a reduction in risk of death of 13% over those not receiving adjuvant therapy (p=0.000). ER negative cases treated with chemotherapy showed a risk reduction of 23% over those not receiving chemotherapy (p=0.000).

PI3 Kinase Pathway Analysis in Tissue Microarrays Using Laser Capture Microdissection and Immunohistochemistry

Background. During the performance of the BCIRG trials primary patient tumor samples were obtained from paraffin blocks and assembled into 15 tissue microarrays, including 3000 samples from trial 005 (adjuvant taxol in Her2- node positive patients), 2200 in 006 (adjuvant herceptin in Her2+ high risk patients) and 300 in 007 (addition of platinum in Her2+ first line therapy). This array set was prepared prospectively, in anticipation of molecular epidemiologic studies of a variety of targets in relation to outcome. In order to address the potentially important role of the PIK3CA pathway in modulating outcome in different clinical situations we assessed components of the PIK3CA pathway by various methods.Methods. We analysed the expression of PTEN, Cyclin D1, p53 and Stathmin by immunohistochemistry using standard methods. All markers were scored by histoscore. Phospho S6 240 and phospho Akt 473 were assessed simultaneously by quantum dot immunofluorescence using automated image capture and segmentation. PIK3CA mutations were evaluated using SnaPshot analysis of laser captured TMA spots in a subset of approximately 2000 samples.Results. In the samples analyzed PIK3CA mutation had an incidence of 23%, with 9% being mutations in exon 9 and 13% in exon 20, with 0.5% being mutant in both exons. Initial analysis of the results prior to outcome analysis indicated that Stathmin expression, while being a robust marker with good dynamic range, did not appear to correlate with PTEN loss by IHC or with PIK3CA mutation.Conclusions. PIK3CA mutational analysis is feasible from TMA cores and gives mutation incidences similar to the published literature for archival material. Relationships of markers with outcome will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4043.

Bone fractures among postmenopausal patients with endocrine-responsive early breast cancer treated with 5 years of letrozole or tamoxifen in the BIG 1-98 trial

BACKGROUND

To compare the incidence and timing of bone fractures in postmenopausal women treated with 5 years of adjuvant tamoxifen or letrozole for endocrine-responsive early breast cancer in the Breast International Group (BIG) 1-98 trial.

METHODS

We evaluated 4895 patients allocated to 5 years of letrozole or tamoxifen in the BIG 1-98 trial who received at least some study medication (median follow-up 60.3 months). Bone fracture information (grade, cause, site) was collected every 6 months during trial treatment.

RESULTS

The incidence of bone fractures was higher among patients treated with letrozole [228 of 2448 women (9.3%)] versus tamoxifen [160 of 2447 women (6.5%)]. The wrist was the most common site of fracture in both treatment groups. Statistically significant risk factors for bone fractures during treatment included age, smoking history, osteoporosis at baseline, previous bone fracture, and previous hormone replacement therapy.

CONCLUSIONS

Consistent with other trials comparing aromatase inhibitors to tamoxifen, letrozole was associated with an increase in bone fractures. Benefits of superior disease control associated with letrozole and lower incidence of fracture with tamoxifen should be considered with the risk profile for individual patients.

BCIRG 007: First overall survival analysis of randomized phase III trial of trastuzumab plus docetaxel with or without carboplatin as first line therapy in HER2 amplified metastatic breast cancer (MBC)

LBA1008

Background: Based on preclinical synergism between docetaxel (T), carboplatin (C) and trastuzumab (H), BCIRG conducted a phase III trial in HER2-positive MBC to evaluate efficacy and safety of H in combination with T or TC. Methods: 263 patients (pts) with HER2 FISH+ MBC were randomized to TH (H with T 100mg/m2) or TCH (H with T 75mg/m2 and C AUC=6). Chemotherapy was given every 3 weeks (q3w) for 8 cycles with weekly H at 2mg/kg (loading dose of 4 mg/kg) followed by H q3w at 6 mg/kg until progression. Pts were stratified by centre and prior (neo) adjuvant taxane chemotherapy. Primary endpoint was Time To disease Progression (TTP). Secondary endpoints include overall survival, response rate, duration of response (DR), clinical benefit (CB) and safety. Results: 131 pts were treated in each arm Pt characteristics were well balanced in both groups. A first efficacy analysis was conducted at 204 events. There was no significant difference between TH and TCH in median TTP (11.1 vs 10.4 mos, p=0.57), ORR (73% in both arms), DR (10.7 vs 9.4 mos) and CB (67% in both arms). At 39 months of median follow-up, median overall survival was 36.40 and 36.57 months in TH and TCH arms respectively. More patients on TCH received the max number of chemotherapy cycles, and numerically fewer patients on TCH discontinued treatment as a result of non hematological toxicity. The most common gr 3/4 toxicities were: Neutropenic infection that was 16.8% vs 9.2% respectively for TH and TCH, thrombocytopenia (2% vs 15%), asthenia (5% vs 12%), anemia (5% vs 11%), and diarrhea (2% vs 10%). Two pts died (1.5%) due to sepsis in TCH. Absolute LVEF decline > 15 % were seen in 5.5 % vs 6.7 % of pts. One pt (0.8%) had a symptomatic CHF in TH arm. Conclusion: Both TH (T 100) and TCH (T 75) were highly effective treatment regimens in women having HER2-positive MBC, demonstrating high response rates, median TTP > 10 months, and median overall survival > 36 months in both TH and TCH. Cardiac toxicity was no significant problem with either treatment.

[Table: see text]

BCIRG 006: Docetaxel and trastuzumab-based regimens improve DFS and OS over AC-T in node positive and high risk node negative HER2 positive early breast cancer patients: Quality of life (QOL) at 36 months follow-up

19647

Background: The primary objective of the BCIRG 006 trial was to determine if the use of trastuzumab in early high-risk HER2-positive breast cancer significantly improved clinical outcomes. A secondary objective was to evaluate the QOL of patients receiving the 2 treatments. Methods: The BCIRG 006 trial compared adjuvant standard AC (doxorubicin/cyclophosphamide x 4 cycles) followed by docetaxel x 4 [AC-T] or 2 trastuzumab-containing regimens, AC followed by T with trastuzumab x 1 year [AC-TH] or TCarbo x 6 with trastuzumab x 1 year [TCH] in patients with node positive or high-risk node negative HER2-positive early breast cancer (n=3222). Results: The 2nd planned interim analysis, median follow-up at 36 months, showed that both AC-TH and TCH significantly improved the DFS and OS over the control (relative reduction risk of relapse 39% (P<0.0001) and 33% (P=0.0003) respectively, for AC-TH and TCH vs control). Relative reduction in the risk of death was 41% (P=0.0041) and 34% (P =0.017) respectively, for AC-TH and TCH vs control. Congestive heart failure occurred in 0.4% of patients in AC-T and TCH vs 1.9% of patients in AC-TH. Global safety profile was acceptable in all 3 arms and more favourable in TCH than AC-TH. QOL, a secondary endpoint of this trial, was assessed using the EORTC QLQC-30, BR-23, and EQ5D. We will present the primary QOL endpoints comparing Physical Function, Global Health Status, Future Perspectives, and Systemic Treatment Effects change scores from baseline to mid-chemotherapy, end of chemotherapy, and 12 months follow-up (with a 10% change considered clinically important). The proportion of patients with improved/stable/worsened QOL scores will be compared with chi-square tests. Other QOL exploratory analyses will be presented.

[Table: see text]

Effect of early detection of occult brain metastases in HER2-positive breast cancer patients on survival

1015

Aim: The aim of the study was to compare disease free survivals (DFS), survivals from the detection of brain metastases, overall survivals (OS) and the causes of death between two patient groups: group I with disseminated HER2-positive breast cancer and occult brain metastases and group II with symptomatic brain metastases. Material and Methods: MRI screening of the brain was performed in 80 HER2-positive breast cancer pts treated with trastuzumab and cytostatics for visceral metastases. In 29 pts (34%) in whom occult brain metastases were detected, whole brain radiotherapy (WBR) to the brain (30 Gy in 10 fractions) was performed (Group I). They were compared with 48 pts with symptomatic brain metastases treated at the same clinic during the same time period (Group II). Both groups were comparable regarding the site of distant metastases and the type of treatment. All pts in both groups had distant metastases to the lung and/or liver. Results: Median DFS in group I was 17 months and in Group II- 19.9 months (p=0.61). Median survival from dissemination of the disease (visceral metastases) to the detection of occult and symptomatic brain metastases was 9 and 15 months, respectively (p=0.21). Median survival calculated from the detection of brain metastases was 9 and 9.3 months, respectively (p=0.76). Median OS of pts with occult and symptomatic brain metastases was 53.8 and 52 months, respectively (p=0.79). In the group with occult brain metastases 15% of pts died because of progression in the brain and in the group of symptomatic brain metastases the rate of cerebral death was 48%. Conclusions: WBR performed during the asymptomatic period decreased the rate of cerebral deaths, but did not prolong overall survival. Screened MRI of the brain during the asymptomatic period did not improve the outcome of pts with HER2-positive breast cancer and with visceral metastases.

No significant financial relationships to disclose.

BCIRG 007: Serum HER2 levels in women with metastatic HER2-amplified breast cancer

1020

Background: BCIRG 007 is a multicenter, phase 3 randomized trial comparing docetaxel and trastuzumab (TH) with docetaxel, platinum salt (cisplatin or carboplatin) and trastuzumab (TCH) as first line chemotherapy in women with metastatic breast cancer (MBC). Women enrolled in the study had to have primary breast tumors with HER2 amplification as determined by centralized FISH analysis. Methods: We determined the percentage of subjects with HER2 amplification who had elevated (>15ng/mL) baseline levels of serum HER2 prior to the initiation of trastuzumab-based therapies. Baseline was considered to be the last available determination within 21 days prior to first treatment. Results: The median baseline serum HER2 levels was 75.8 ng/mL (range=8–3,280 ng/mL) for all subjects (n=123), with no statistical difference between subjects randomized to receive TH (median=65.9 ng/mL, n=64) and those randomized to receive TCH (median=89.9 ng/mL, n=59). Overall, 89% of the 123 subjects with HER2-amplified primary tumors had serum HER2 levels >15 ng/mL at the time of metastatic disease (86% in TH vs 92% in TCH). Conclusions: There was no statistical impact of baseline serum HER2 levels on any important clinical event: response to treatment, clinical benefit (response or stable disease for more than 24 weeks), disease progression or death. Conversely, when serum HER2 was measured over time, subjects with higher levels had an elevated risk of experiencing progressive disease (p=.003), even after adjustment for extent of disease (1 or 2 vs 3 or more organs involved) and presence of visceral disease. These analyses suggest that monitoring serum HER2 levels over the course of disease may be a means for detecting progressive disease in women with HER2 amplified breast cancer. Given the long intervals between the serum HER2 measurement and progression (up to 9 months), caution is required in interpreting these results.

No significant financial relationships to disclose.

Alteration of topoisomerase II-alpha gene in human breast cancer and its association with responsiveness to anthracycline- based chemotherapy

524

Background: Topoisomerase II-alpha (TOP2A) gene amplification, and not HER2 amplification, may be the predictive marker for responsiveness to anthracycline chemotherapy. Methods: To address this issue we performed a test set-validation set series of analyses. Amplification of TOP2A and HER2 was evaluated by fluorescence in situ hybridization (FISH) in patients with metastatic breast cancer who participated in a randomized trial (H0648g, n = 469) of anthracycline-based chemotherapy with or without trastuzumab. This group represented the test set. To validate our observations in the H0648g test set we analyzed breast cancers from two other, large, randomized clinical studies of anthracycline-based chemotherapy; one with HER-2 amplification and trastuzumab-based therapy (BCIRG006, n = 3,222) and one without HER-2 amplification and combination-based chemotherapy (BCIRG005, n = 3,298), comparing TOP2A status with clinical outcome. Both of the latter trials were adjuvant trials. Results: In the H0648g test set patients whose breast cancers had TOP2A gene co- amplification and who were treated with doxorubicin, cyclophosphamide (AC) and trastuzumab had a longer progression-free survival compared to those who were treated with AC alone (p = 0.03). Patients treated solely with AC, whose breast cancers had TOP2A gene co-amplification had a statistically significant improvement in duration of survival compared to those without TOP2A gene amplification (p = 0.004). Among all women entered in the HER2-positive BCIRG 006 clinical trial, as well as among women who were treated with anthracycline-containing chemotherapy alone, women whose breast cancers showed TOP2A gene co-amplification had a significantly longer disease-free (p <0.001), recurrence-free (p <0.001) and overall survival (p = 0.01) compared to women whose breast cancers lacked TOP2A amplification. Unexpectedly, the added beneficial effect of trastuzumab was not seen among TOP2A co-amplified breast cancer patients in the larger BCIRG006 trial. Conclusions: In patients treated with chemotherapy alone the findings demonstrate that TOP2A gene co-amplification is a useful predictive marker of responsiveness to anthracycline-containing chemotherapy.

No significant financial relationships to disclose.

Oral vinorelbine/paclitaxel combination treatment of metastatic breast cancer: a phase I study

PURPOSE

Intravenous (i.v.) vinorelbine (VRL) generally given on days 1 and 8 of an every three-week cycle in combination with paclitaxel (PTX) is an effective option for the treatment of metastatic breast cancer (MBC). In an effort to improve both patient and chemotherapy unit convenience, oral VRL was used at equivalent doses of i.v. VRL.

PATIENTS AND METHODS

The maximal tolerated dose (MTD) was determined during the first cycle of oral VRL given on days 1 and 8 or 15 and PTX infused over 3 h on day 1 every 3 weeks, maximum of 6 cycles. The dose of oral VRL was escalated from 60 to 80 mg/m2 in 10 mg/m2 increments. Paclitaxel was administered at 110 and then 135 mg/m2. The combination regimen was given as first-line chemotherapy of MBC. Three to six patients per cohort were treated.

RESULTS

Twenty-two patients were treated in the first four cohorts (oral VRL/PTX): 60/110, 70/110, 80/110 and 80/135. In cohort 4, seven patients were treated, one patient being non-evaluable for MTD, three of them presented a dose-limiting toxicity (DLT) consisting of febrile neutropenia and neutropenic infection. Therefore 80/135 was the MTD. Because 36% of oral VRL administrations on day 8 were delayed to day 15 at 80/110, two additional cohorts were tested: in cohort 5, oral VRL 60 mg/m2 on days 1 and 15 and PTX 135 mg/m2 on day 1 and in cohort 6, oral VRL 80 mg/m2 on days 1 and 15 and PTX 110 mg/m2 on day 1, every 3 weeks. In cohort 5, six out of eight patients had DLTs: omission of oral VRL on day 15 for five patients, grade 4 neutropenia>7 days for another one. Therefore the recommended dose (RD) for further clinical testing was oral VRL 80 mg/m2 on days 1 and 15 and PTX 110 mg/m2 on day 1 of an every 3-week cycle. Two of the three evaluable patients treated at the RD had a partial response. The pharmacokinetics of VRL and PTX is being analysed and will be further presented in a separate publication.

CONCLUSIONS

This phase I study has determined the doses of oral VRL and PTX to be used in combination for the benefit of the patient and of the chemotherapy unit in term of nurse's workload. The recommended regimen of oral VRL 80 mg/m2 on days 1 and 15 and PTX 110 mg/m2 on day 1 given every 3 weeks will be further tested in phase II.

BCIRG 007: Randomized phase III trial of trastuzumab plus docetaxel with or without carboplatin first line in HER2 positive metastatic breast cancer (MBC)

LBA516

Background: Based on preclinical synergism between docetaxel (T), carboplatin (C) and trastuzumab (H), BCIRG conducted a phase III trial for women with HER2+ MBC to evaluate efficacy and safety of H in combination with T or TC. Methods: 263 patients (pts) with HER2 FISH+ MBC were randomized to TH, (H with T 100 mg/m2) or TCH, (H with T 75 mg/m2 and C AUC=6). Chemo was given q3 wks for 8 cycles with wkly H at 2 mg/kg (loading dose of 4 mg/kg), followed by H q3 wks at 6 mg/kg until progression. Pts were stratified by centre and prior (neo) adjuvant taxane chemotherapy. Primary endpoint was TTP with 80% power (0.05 significance) to detect a 50% improvement in median TTP between the 2 arms. Secondary endpoints include overall survival, response rate, duration of response (DR), clinical benefit (CB) and safety. Results: 131 pts were treated in each arm. Pt characteristics were well balanced in both groups. Importantly, only 52% of pts received C at the protocol specified dose (RDI > 0.9). Efficacy analysis was conducted at 204 events. There was no significant difference between TH and TCH in median TTP (11.1 vs 10.4 mos, p = 0.57), ORR (73% in both arms), DR (10.7 vs 9.4 mos) and CB (67% in both arms). The most common gr 3/4 toxicities were: infection (44% vs 30%), neutropenic infection (22% vs 12%), thrombocytopenia (2% vs 15%), febrile neutropenia (12% vs 13%) asthenia (5% vs 12%), anemia (5% vs 11%), and diarrhea (2% vs 9%). Two pts died (1.5%) due to sepsis in TCH. Absolute LVEF decline > 15% were seen in 5.5% vs 6.7% of pts. One pt (0.8%) had a symptomatic CHF in TH arm Conclusions: The already effective TH regimen does not benefit from the addition of C, when the T dose in TH is 100 mg/m2 and 75 mg/m2 in TCH, in women with HER2+ MBC.

No significant financial relationships to disclose.

Sensitivity to further endocrine therapy is retained following progression on first-line fulvestrant

There is a need for new endocrine agents that lack cross-resistance with currently available treatments to extend the endocrine treatment window and delay the need for cytotoxic chemotherapy. This retrospective analysis evaluated the response of postmenopausal patients with previously untreated metastatic/locally advanced breast cancer to further endocrine treatment following progression on first-line fulvestrant or tamoxifen. Patients received fulvestrant 250 mg (intramuscular injection every 28 days) plus matching tamoxifen placebo (once daily), or tamoxifen 20 mg (orally once daily) plus matching fulvestrant placebo (every 28 days) in a double-blind, randomized, phase III trial. Treatment continued until disease progression or withdrawal, when further endocrine therapy was initiated (at the treating physician's discretion). Information regarding subsequent therapies and responses was obtained by follow-up questionnaire. Two-hundred-and-forty-five questionnaires were returned (from 587 patients), 149 of which yielded follow-up data on patients receiving second-line endocrine therapy following fulvestrant (n=83) and tamoxifen (n=66). Second-line therapy produced objective responses (OR) in 6/44 (13.6%) and clinical benefit (CB) in 25/44 (56.8%) patients who had CB with fulvestrant and produced OR in 5/41 (12.2%) patients and CB in 27/41 (65.8%) patients who had CB with first-line tamoxifen. For patients deriving no CB from trial therapy, second-line therapy produced OR in 3/39 (7.7%) and CB in 15/39 (38.5%) patients in the fulvestrant group and OR in 4/25 (16.0%) and CB in 12/25 (48.0%) patients in the tamoxifen group. Results from this questionnaire-based study suggest that postmenopausal women with advanced breast cancer who respond to first-line fulvestrant or tamoxifen retain sensitivity to subsequent endocrine therapy.