Abstract P5-04-02: Biopsy of metastases impacts treatment choice and patient outcome in breast cancer – Final results of the WSG/DETECT PRIMET study

Background: Changes in tumor biology (e.g., hormone receptor (HR) / HER2 status or grading) between primary tumor (PT) and metastatic tissue (MT) could impact outcome and treatment choice following first recurrence in breast cancer (BC).

Methods: PRIMET is a prospectively planned, retrospective multicenter quality assurance study comparing BC phenotype in tissue from PT, involved lymph nodes (LN) of primary disease, and disease recurrence (DR). PRIMET comprises 635 patients from WSG and DETECT trial groups (11 centers), whose BC was diagnosed between 1980 and 2010; follow-up continued until mid-2012. Patients with unilateral primary BC suffering subsequent local-regional and / or distant DR (LDR / DDR) were included. Clinical data including ER, PR, HER2, and grade were obtained from a systematic chart review in PT and DR; in two centers, these factors were also measured in LN by central pathology. Dependence of post-recurrence survival (PRS) on changes in tumor biological factors was analyzed.

Results: Data from 635 patients (including 592 cM0, of whom 46% had LDR only) were available for analysis. Median follow-up in patients alive at analysis was 101 months. Considering cM0 patients, median overall survival (OS) was 176 months; median recurrence-free survival (RFS) was 48 months (DDR present: 45 months; LDR only: 50 months). Median PRS was 59 months (DDR present: 45 months; LDR only: 127 months). In patients with first DR within 18 months, median PRS was 29 months, in others 79 months. HR status in PT/MT was: 61.5% (+/+), 13.2% (+/-), 5.5% (-/+) 19.8% (-/-). Of the HR “switches” in either direction with LN biopsy available, about half already occurred in lymph nodes. HER2 status in PT/MT was: 14.6% (+/+), 6.7% (+/-), 14.9% (-/+) 63.8% (-/-). With LN biopsy available, most losses of HER2 overexpression were already observed in LN tissue, whereas acquired HER2 overexpression was observed in about half of LN biopsies. Triple negative (TN: HR-, HER2-) percentages were 74.4% (non-TN/non-TN), 9.0% (non-TN/TN), 6.1% (TN/non-TN), 10.5% (TN/TN).

Compared to HR+/+, loss of HR+ status (HR+/-) was significantly associated with poorer PRS (hazard ratio: 1.62; p = 0.01). Significantly better PRS was associated with a switch from G3 to G1/2 (hazard ratio: 0.47; p = 0.02). Tumors that switched to TN or that lost HER2 overexpression showed trends toward poorer PRS. Persistent TN was associated with poorer PRS than other combinations.

Among patients with DDR, metastasis in bone only was associated with better PRS than primary or visceral (CNS, lung, liver, etc.) metastasis. Among patients with visceral metastasis, negative HR status in metastasis was associated with poorer survival than in HR+/+ not only for HR-/- (p = 0.02), but also for HR+/- (p = 0.04).

Conclusions:

Tumor biology of primary and metastatic tissue differed in a substantial fraction of patients (HR: 19%; HER2: 22%, TN: 18%); more than half of all changes occurred already in LN. Status changes particularly loss of HR+ status, had significant prognostic impact. We can expect a switch in HR or HER2 status (or both) in about 38% of metastatic tissue biopsies, with presumably important clinical therapeutic consequences, in particular regarding targeted therapies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-02.

Abstract P6-05-11: Run-in phase of prospective WSG-ADAPT HR+/HER2- trial demonstrates feasibility of early endocrine sensitivity prediction by recurrence score and conventional parameters in clinical routine

Background: Despite promising evidence regarding outcome prediction, endocrine sensitivity, as determined by proliferation response to short-term preoperative endocrine therapy, is currently not included in adjuvant chemotherapy decisions in early HR+/HER2- breast cancer (BC).

Methods: The prospective WSG-ADAPT HR+/HER2- trial includes early BC patients with 0-3 positive LN who are candidates for adjuvant chemotherapy based on clinical-pathological criteria alone; it aims to spare chemotherapy in a substantial proportion utilizing a combination of genomic assessment by Oncotype DX and endocrine sensitivity testing. All patients received 3-week preoperative endocrine induction therapy (ET): aromatase inhibitors (AI) if postmenopausal, tamoxifen if premenopausal. Patients with low (0-11) Recurrence Score (RS) or intermediate RS (12-25) and ET response (centrally tested, post-therapy Ki-67 <10%) are recommended to forego adjuvant chemotherapy (“low-risk” patients). Distribution of RS, responder percentages in each group, and impacts of RS, ET regimen, and initial Ki-67 on post-therapy Ki-67 are reported here.

Results: As of 6/2013, 380 patients from 30 study centers had been enrolled in the ADAPT HR+/HER2- trial. Median age was 54 years. At first pre-planned analysis (5/2013), paired Ki-67 measurements (pre-/post-therapy) were available in 241 patients; RS was available in 208 cases (201 with paired Ki-67). RS was low in 21.6%, intermediate in 57.7%, and high in 20.7%; the respective risk group responder percentages (post-treatment Ki 67 <10%) were 84.1%, 73.9%, and 40.0% (p<0.001 when comparing low/intermediate vs. high, chi-square). In particular, these percentages support the pre-trial estimate of >70% endocrine responders in the intermediate genomic risk group, who could potentially be spared adjuvant chemotherapy. Median Ki 67 level decreases (as percentage of pre-treatment value) were 25% in premenopausal patients (tamoxifen, n = 101) vs. 75% in postmenopausal patients (AI, n = 115) (p<0.001, Mann-Whitney); median decreases by RS group were similar, 61% (low), 53% (intermediate) and 56% (high), respectively (p = 0.81, Kruskal-Wallis). In linear regression, pre-treatment Ki-67, endocrine regimen/menopausal status, and RS were all independent predictors for post-treatment Ki 67. Final run-in-phase analysis and validation will be presented after completion of endocrine induction therapy in 400 patients.

Conclusions: The Run-In Phase of the WSG ADAPT HR+/HER2- trial confirms trial design estimates of RS and proliferation response to induction ET. It indicates that the multicenter prospective ADAPT concept combining static and dynamic biomarker assessment for individualized therapy decisions in early BC is feasible. Proliferation response was strongly associated with therapy group (AI/post-menopausal vs. tamoxifen/pre-menopausal). Survival non-inferiority of intermediate Recurrence Score proliferation responders vs. low Recurrence Score patients (active control) will be tested in the ADAPT main phase to determine if adjuvant chemotherapy can be spared in 70% of patients with 0-3 positive LN classified as “intermediate risk” by conventional factors.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-11.

P1-06-03: Predictive Value of HER2, Topoisomerase-II (Topo-II) and Tissue Inhibitor of Metalloproteinases (TIMP-1) for Efficacy of Taxane-Based Chemotherapy in Intermediate Risk Breast Cancer – Results from the EC-Doc Trial

Background: Despite extensive research, there is still no consensus on optimal predictors for use of taxane-based chemotherapy (cht) in early breast cancer. Some studies have revealed HER2 as a significant predictive marker for efficacy of taxanes and anthracyclines. TIMP-1 and Topo-II are reported to be predictive for anthracycline efficacy. In our previous reports, both Ki-67≥20% and central G3 status emerged as significant predictors for taxane benefit. We have now compared HER2 and Topo-II (as protein expression and gene amplification) and TIMP-1 immunoreactivity as well as factor combinations (HT (HER2/TIMP-1) and 2T (Topo-II/TIMP-1) regarding their predictive value for benefit from taxane-based cht.

Methods: The EC-Doc trial randomized 1950 patients with 1–3 positive LN to 6x CEF/CMF vs. 4xEC-4xDoc. Significantly better DFS and OS favoring EC-Doc have been previously reported (Nitz et al., SABCS 2008). Protein expression and gene amplification data as well central histology/grade were available for 772 patients. Survival analysis was performed using Cox proportional hazards and Kaplan-Meier statistics. Analysis of HER2 survival impact status was prospectively planned.

Results: The entire and the investigated study populations did not differ regarding baseline characteristics. After median follow up of 64 months, both DFS (5y 90% vs. 80%, p=0.006) and OS (5y 95% vs. 92%, p=0.022) rates significantly favored EC-Doc vs. CEF in this cohort as well. HER2 over-expression (3+ and/or FISH≥2.0) was reported in 158 tumors (20%), Topo-II aberration (deletion or amplification) was reported in 78 (49.4%) HER2+ and in 83 (13.6%) HER2−negative tumors; 496 tumors were classified as TIMP-1 immunoreactive (65.2%). None of these factors were significantly prognostic for EFS in this collective. Regarding DFS, EC-Doc was strongly superior to FEC in HER2+ tumors (HR=0.29, 95%CI: 0.12−0.7, p=0.006) but not in HER2− tumors (p=0.18). In Topo-II aberrated tumors, the benefit of EC-Doc was remarkably strong (HR=0.28, 95% CI: 0.11−0.69, p=0.006), whereas the benefit was not significant in Topo-II normal tumors (p=0.16), which comprise more than ¾ of the total. In contrast, Topo-II protein overexpression (>10%) was not associated with a stronger benefit in either subgroup. The superiority of EC-Doc to FEC was significant in the larger group of TIMP-1 immunoreactive tumors (HR=0.57, p=0.025) but not in TIMP-1 negative tumors (p=0.14), similar behavior was seen in “HT” and “2T” subgroups (significance with HR about 0.5 in the “+” subgroups). In a multivariate model for DFS including age, tumor size, Ki-67, central grade, HR, HER2, TOPO_II aberration, TIMP-1 status, therapy and interactions of all these factors with therapy arm, the only significant therapy interaction was that of (high) Ki-67 (HR=0.76, 95% CI: 0.59−0.98, p=0.03); significant main effects in this model were age, central grade, and Ki-67.

Conclusions: These data suggest predictive significance for Topo-II aberration, TIMP immunoreactivity and HER2 over-expression as well as a multivariate predictive significance of high Ki-67 for enhanced benefit of taxane-based cht.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-03.

Abstract P2-09-14: Evidence for Predictive and Prognostic Impact of Molecular Classification in Taxane-Based Chemotherapy in Intermediate Risk Breast Cancer — An Analysis of the WSG EC-Doc Trial

Background: Patients with hormone receptor positive breast cancer (BC) and 1-3 positive lymph nodes (LN) belong to the intermediate risk-group. Among these patients chemoendocrine therapy may be considered. The prognostic role of molecular breast cancer subgroups and their predictive impact regarding taxane-and anthracycline based chemotherapy is unclear. This analysis evaluated the ability of molecular subtypes to predict outcome after standard FEC or EC-Doc chemotherapy in pts with 1-3 positive LN.

Methods: The EC-Doc trial randomized 2012 patients with 1-3 positive LN to 6x FEC/CMF vs. 4x EC followed by 4 x docetaxel (Doc). Significantly better DFS and OS in favor of EC-Doc was reported previously (Nitz et al., SABCS 2008). Protein expression data and central histology/grade (G) were available for 772 patients (Control n=390; EC-Doc n=382). Protein expression was measured on tissue micro arrays for ER, PR, Her2 (both IHC/FISH), Ki-67, Ck 5/6, and EGFR. Molecular subgroups were classified using ki-67 cutt-off of 13.25 % (Cheang et al. JNCI 2009). Results: There was no difference in baseline characteristics (age, LN, grade, tumor size, HR) between the entire ITT-study population and the investigated cohort of 772 pts. There were significantly more G 3 tumors in the basal and Her2 group and more G 1/2 tumors in the luminal A cohort. Distribution of molecular subtypes is as follows:

- Luminal A: HR+ (ER and/or PR+), low KI-67 and Her2-: 26.1%

- Luminal B: HR+ and either Ki-67 high or Her2+: 44.8%

- Her2: HR-and Her2+: 10.9%

- Triple negative (TN) basal-like ER/PR/Her2- ; Ck 5/6+ and/or EGFR+: 11.8%

- TN non-basal-like: TNBC; both Ck 5/6 and EGFR-: 6.4%

After median follow up of 64 months, both DFS (5y 90% vs. 80%, p=0.006) and OS (5y 95% vs. 92%, p=0.022) rates also significantly favored EC-Doc vs. FEC in this cohort. DFS rates were highest in luminal A and lowest in TN basal-like tumors.

In univariate analysis a significant benefit of EC-DOC vs. FEC for DFS is seen in luminal B patients (p=0.004; HR=0.41; (0.22-0.77)). EC-Doc was also better than FEC in HR-patients who were not “basal-like (p=.057; HR=0.385 (0.14 — 1.07).

In multivariate analysis including age, nodal status, tumor size, molecular subtypes, and chemotherapy regimen age, luminal A subtype, and interaction of EC-Doc and luminal B subtype (HR=0.44) influenced significantly DFS survival. Conclusions: These data provide evidence that molecular subtypes are associated with both different levels of benefit from EC-Doc and different DFS within each treatment group. These retrospective results will be validated within the prospective WSG PlanB trial.

Table/Figure 1: multivariate model for DFS

Tabid Parameters bssdciated with benefitfrctm EC-Dgccompared to CEF in a multivariate tnofiel tor DFS

Abstract P4-06-22: Persistent Triple-Negative Phenotype Is Associated with Poorest Outcome among Patients with Metastatic Breast Cancer (BC) - Results of the Retrospective Multicenter PriMet Study Comparing Molecular BC Phenotypes in Primary Tumors and Corresponding Recurrences

Background: Patients with triple negative (TN) breast cancer (BC), defined by lack of both ER/PR expression and HER2 overexpression, have an unfavorable prognosis. Although phenotype changes between primary tumor (PT) and disease recurrence (DR) have been described, their clinical significance is still unclear.

Methods: We conducted PriMet, a retrospective multicenter (n=11) study to compare BC phenotype in PT and corresponding DR. Inclusion criteria comprised (1) unilateral BC with subsequent/synchronous local/regional/distant DR and (2) immunohistochemical confirmation of DR. Our aim was to (a) evaluate discordance rates between PT/DR, (b) find predictors for discordance, and (c) analyze the impact of discordance on patient outcome.

Results: 436 patients were entered into PriMet; 414 had no evidence of primary metastatic disease (M0). Median follow-up in patients alive at time of analysis was 73. 1 (4.4-293.6) months. Triple receptor status for PT and DR was available in 377 patients; 68 patients (18.0 %) showed TNBC in PT, 40 patients (10.6 %) had TNBC in both PT and DR (i.e. TNBC persistence); 28 patients (7.4 %) changed from TNBC to non-TNBC (15 became HER2 positive (4.0 %)). Status changes for ER and PR were significantly positively associated (P<0.001). Patients with either persistent TNBC or non-TNBC had a median age at diagnosis of 52.0 compared to 55.5 yrs for patients with discordant TN status (p=0.04). Compared to differing constellations, persistent TNBC was associated with higher tumor grade (p=0.018) as well as with both decreased disease-free survival (DFS) (see figure) and post-recurrence survival (PRS) in M0 patients. In multivariate analysis containing pT stage, nodal stage, tumor grade in PT, TNBC in PT and TNBC persistence, TNBC persistence remained significantly associated with decreased DFS and PRS.

Conclusion: PriMet provides substantial evidence regarding potential phenotype changes in PT vs. DR and underlines the importance of immunohistochemical DR verification even in initially TN disease. TNBC persistence was significantly associated with adverse patient outcome.

Impact of expression differences of kallikrein-related peptidases and of uPA and PAI-1 between primary tumor and omentum metastasis in advanced ovarian cancer

BACKGROUND

Primary tumor levels of serine proteases of the kallikrein-related peptidases (KLK) family as well as urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1 impact disease course in ovarian cancer. The changes in levels of these factors from primary tumor to omentum metastasis ('level differentials') could thus be associated with metastastic processes.

PATIENTS AND METHODS

Protein levels of seven tissue KLK (KLK5-8, 10, 11, 13), uPA, and PAI-1 were determined in extracts of primary tumor tissue and corresponding omentum metastasis of 54 ovarian cancer patients.

RESULTS

Higher level differentials of KLK5-8, 10-11, and uPA were associated with residual tumor >10 mm. Residual tumor and larger level differentials of KLK5-7, 10, and uPA were associated with disease progression in the whole cohort. Remarkably, level differentials of KLK5-8 and 10-11 strongly impacted disease progression even in patients with residual tumor mass ≤10 mm; hence, the observed impact of level differentials in KLK5-7 and 10 on disease progression was not simply attributable to their association with surgical success.

CONCLUSION

Since they impact both surgical outcome and survival in advanced ovarian cancer, measurement of level differentials could support clinical decisions on surgical and systemic therapy or help in patient selection for novel targeted therapies.

Impact of tumor biology, particularly triple-negative status, on response to pre-operative sequential, dose-dense epirubicin, cyclophosphamide followed by docetaxel in breast cancer

BACKGROUND

The central objective of this study was to determine the predictive impact of several established tumor biological factors (PgR, ER, HER2 and Ki-67) on response to pre-operative chemotherapy in primary breast cancer.

PATIENTS AND METHODS

59 primary M0 breast cancer patients received pre-operative sequential dose-dense epirubicin and cyclophosphamide followed by docetaxel (19 patients at dosage 100 mg/m(2), 40 patients at 75 mg/m(2)).

RESULTS

Pathological complete remission (pCR) occurred in 17 patients (29%) and at least partial remission in 42 (71%). Higher proliferation (Ki-67) and lack of hormone receptors (either or both) were significant predictive factors for pCR; moreover, 8/11 (73%) patients with triple-negative tumors (HER2(-)/ER(-)/PgR(-)) had pCR (p=0.001). Breast conserving surgery was achieved in 46/59 patients (78%). Hand-foot syndrome occurred in 12/19 patients treated at the higher docetaxel dosage but only 1/40 of the remaining patients. Higher docetaxel dosage was associated with improved pCR in the non-triple-negative subgroup.

CONCLUSION

The tumor biology of hormone receptor-negative, especially triple-negative, and highly proliferating breast cancer is associated with strongly positive response to dose-dense, pre-operative epirubicin/cyclophosphamide/docetaxel chemotherapy.

Outcome Prediction in Node-Negative Breast Cancer Based on ASCO-Recommended Biomarkers uPA/PAI-1 Using the Final 10-Year Analysis of the Randomized Multicenter Chemo N0 Trial Compared to Adjuvant Online™

Background: Based on interim analysis of Chemo N0, the first prospective multicenter randomized clinical trial using biomarkers uPA/PAI-1 for risk stratification and chemotherapy selection in N0 breast cancer, uPA/PAI-1 are now recommended for routine use by ASCO and AGO guidelines. Final 10-year follow-up of Chemo N0 has validated the clinically relevant long-term prognostic and predictive impact of uPA/PAI-1 in N0 breast cancer. To quantify the clinical utility of this impact, outcomes in subgroups defined by these biomarkers were compared to predictions of Adjuvant Online™, the leading validated tool based on established clinical factors. Methods: In Chemo N0, patients (n=647, 1993-98) were prospectively stratified according to uPA/PAI-1: High-risk patients were randomized (6x CMF vs. observation), low-risk patients observed. Retrospectively, we divided recruited patients into two groups (chemotherapy vs. no adjuvant therapy) and stratified using uPA/PAI-1 (low vs. high). Individual 10-year OS was calculated by www.adjuvantonline.org (Version 7.0); these estimated values were compared to the observed Chemo N0 10-year OS. Results: 383/647 patients have complete 10-year follow-up data. Median 10-year OS estimated by Adjuvant Online™ was 80.5% taking into account administered adjuvant therapy; 10-year Chemo N0 follow-up revealed observed 10-year OS of 74.7% (97/383 died). 77.8% (298/383) did not receive chemotherapy: In high-risk, untreated patients (n=137), 10-year OS was 72.3% vs. estimated 81.1%. In CMF-treated patients (all high-risk, n=85), observed OS was 61.2% vs. estimated 76.4%. Conclusions: For the first time, risk assessment by novel biomarkers is compared to that by Adjuvant Online™ in final data from a randomized prospective clinical trial. In patients with high uPA/PAI-1, the individual 10-year risk calculated by Adjuvant Online™ seems to be underestimated compared to observed patient outcome. Tumor-biological information provided by validated biomarkers thus has the potential of enhancing epidemiology-based risk estimation using only established factors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4038.

Interim analysis of the multicenter phase II HEDON trial evaluating pathological response to pre-operative docetaxel and docetaxel+trastuzumab (T) in locally advanced breast cancer (BR) stratified by HER2-status

e11512

Background: Docetaxel is the most effective mono-substance in metastatic BC and highly effective in adjuvant chemotherapy. Early docetaxel-monotherapy data in primary systemic therapy (PST) showed a pCR of 18% (Amat et al; 2003), comparable with pCR-rates of standard PST combination chemotherapy. HEDON was conducted to evaluate efficacy of docetaxel ± T with regard to pCR (defined as absence of invasive and non-invasive BC in breast and lymph nodes) as primary endpoint; secondary endpoints were safety, breast conservation rate and 5-yr DFS. Additionally Trans-HEDON includes a translational research program to identify molecular RNA and methylation (DNA) based markers of response to docetaxel-monotherapy. Methods: From 2006 until 2008, the multicenter phase II HEDON trial fully recruited 93 pts, with therapy still ongoing; tumor stages: T2 (23), T3 (11), T4 (5); nodal status: N0 (16), N1–2 (23). Arm A: Docetaxel (100 mg/m2x6) in HER2-negative (n=60) and Arm B: Docetaxel (100 mg/m2x6) in combination with T (18x2mg/kg KG) preoperatively in HER2-overexpressed BC (n=33), followed by surgery and then by adjuvant epirubicin/cyclophosphamide (E90Cx4), radiotherapy if indicated, T for altogether one year, and endocrine therapy in ER+ and/or PgR+ BC. Pre-planned interim analysis (safety and efficacy) was performed after recruitment of 39 pts (Arm A 26, Arm B 13). Results: In Arm A, 7 pts. (26.9%) achieved pCR and 9 pts. (34.6%) pPR. In Arm B, 7 pts. (53.8%) achieved pCR and all 6 others (46.2%) pPR. Neutropenia occurred in 11 pts. (8 with grade 3). Moderate (25%) dose reduction was necessary in 13 pts., and 50% dose reduction in one patient. Conclusion: According to interim analysis of the HEDON trial, docetaxel-monotherapy of 6 cycles at 100mg/m2 q21 (plus T in HER2-positive BC) is an effective and safely administrable PST. There were no unexpected toxicities, and preliminary pCR rates in HER2-neg (26.9%) and HER2-pos (53.8%) pts. were comparable to those of combination chemotherapy. These interim results will be completed by final analysis on the full collective, with molecular predictors from TransHEDON hopefully identifying patients who derive extensive benefit.

[Table: see text]

Results of the German fulvestrant in practice evaluation programme to evaluate the efficacy, safety, tolerability and acceptance of fulvestrant under daily routine conditions

Abstract #6132

Material and Methods: Fulvestrant is an estrogen receptor (ER) antagonist with a distinct mode of action used in the treatment of postmenopausal women with advanced breast cancer progressing or recurring on an antiestrogen. 848 postmenopausal women with ER+ advanced mamma carcinoma, relapsed during or after adjuvant anti-estrogene treatment, or with a disease progression under an anti-estrogene therapy, were enrolled in this Fulvestrant In Practice Evaluation Programme (IPEP). Under daily routine conditions and without intervention by the sponsor regarding selection of subjects, diagnostic procedures or therapeutic decisions relevant data of the fulvestrant therapy was documented over a period of 9 months. Results: The median patient age was 64 years, 52 % of patients had a co-morbidity, 78 % one or more prior palliative therapies. Efficacy: Clinical benefit was observed in 627/848 patients, including 62 complete and 177 partial remissions. Best response was delayed in 115 patients (not seen at 3 months but at 6 months). Estimated 9-month overall survival (OS) was 89%; 9-month event-free survival (EFS) was 71%. Safety: 244 non-serious adverse events by patient were recorded, most commonly General disorders and administration site conditions, gastrointestinal and musculo-sceletal symptoms. Excluding deaths, 7 serious adverse events were recorded (none attributed to fulvestrant); no new or unexpected safety issues arose. 20 patients died during observation. Tolerability: Tolerability was judged as good to very good by the majority of both specialists and patients with stable values at 3, 6 and 9 months. Acceptance of injection: The vast majority of both doctors and patients found the application via injection to be acceptable or very acceptable, the handling was judged by the doctors as mostly good to very good. Conclusion: Fulvestrant treatment was well tolerated and well accepted in this palliative patient collective, no new safety findings occurred. The treatment showed good efficacy with any patient, who had achieved disease stabilization or better after three months being likely to gain survival benefit from prolonged Fulvestrant therapy. Best response often occured delayed.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6132.

YB-1 expression and effectiveness of different dose-intensification strategies in high-risk breast cancer: Five-year follow-up results of prospective randomized WSG-AM-01 trial

563

Background: Y-box binding protein (YB-1), known as oncogenic transcription factor, is associated with up-regulation of MDR1, alters p53 function, and induces growth of an aggressive phenotype. In high-risk breast cancer, the prospective randomized WSG-AM-01 trial has reported significantly better event-free (EFS) and overall survival (OS) for tandem high-dose (HD) vs. dose-dense (DD) chemotherapy, especially in basal-like und HER2 subgroups. The present study examines the interaction of a drug resistant phenotype induced by YB-1 within the WSG-AM-01 collective at 5-year follow-up. Methods: 236 tumors (116 HD/120 DD) of 403 randomized patients (60%) were available for construction of tissue microarrays and determination of molecular classification by k-clustering of expression of 34 protein markers. Immunostaining of YB-1 by specific peptide antibody was scored semiquatitatively by intensity. Associations of YB-1 staining with other protein expression factors were studied by Pearson correlations. Univariate survival was estimated by Kaplan-Meier analysis and tested by log rank statistics. Multivariate survival modeling was performed by a generalized Cox model, with linear proportional hazards terms in the first block and time-varying interactions in the second block. Results: At a median follow-up of 61.7 months, the WSG-AM-01 confirms a significant EFS and OS benefit for HD in HRBC. In 60% of tumors, there was strong YB-1 expression. YB-1 was significantly associated with several proliferation and drug resistance markers, such as p53, EGFR, S6 and with basal-like/Her2 subtypes.YB-1 expression was highly predictive for response to HD: both EFS (HR=0.29, p=0.001) and OS (HR=0.16, p=0.0001) were significantly improved by HD compared to DD for YB-1 positive tumors; these favorable time-varying hazard ratios signify decreases in early (≤3 years) relapses and deaths, respectively. Conclusions: Among all investigated markers, only YB-1 expression was significantly associated by time- varying interaction analysis with efficacy of HD. The results suggest YB-1 as a potential stratification criterion for future trials as well as a target for treatment of drug resistant HRBC.

No significant financial relationships to disclose.

FGFR4 Arg388 allele is associated with resistance to adjuvant therapy in primary breast cancer

625

Background: Bange et al. recently found that a single-nucleotide polymorphism (SNP) at codon 388 of fibroblast growth factor receptor 4 (FGFR4) gene, causing a transmembrane domain missense mutation (Gly388Arg), is associated with outcome in node-positive breast cancer. Methods: This study addresses clinical relevance of this SNP, FGFR4 genotype, phenotype, and HER2 regarding patient outcome and influence of adjuvant systemic therapy in a substantial primary breast cancer collective (n=372; 1987–2002), median follow-up 94.5 months. Treatment was administered according to consensus recommendations at the time: 73 patients (all N0) received no adjuvant systemic therapy; 114 received adjuvant chemotherapy (87% CMF-based), 164 tamoxifen, 10 combined chemo-endocrine therapy, 11 unknown. 128 (36%) patients experienced disease recurrence, 104 (81%) distant relapses; 140 (38%) died. PCR-RFLP-analysis of germ-line polymorphism was performed in uninvolved lymph nodes; FGFR4 and HER2 expression were assessed immunohistochemically in tumor tissue arrays. Primary endpoint was DFS, since it best reflects impact of adjuvant systemic therapy. Results: In 51% of patients, homo- or heterozygous Arg388 allele was present. No correlation existed between FGFR4 genotype and expression or HER2 status. In N0 patients, FGFR4 genotype was not correlated with disease outcome. In N+ patients, however, FGFR4 Arg388 was significantly associated with poor DFS (p=0.02) and OS (p=0.04). Notably, this association seems to be attributable to relatively poor therapy response in Arg388 carriers, reflected in their significantly shorter DFS (p=0.02) and OS (p=0.045) among patients receiving adjuvant systemic therapy. It is also seen as a significant interaction term in a multivariate proportional hazards model with Arg388 carriers having only about half as much benefit from adjuvant systemic therapy as wild-type carriers. Conclusions: Our results show that the previously found association of FGFR4 Arg388 genotype with breast cancer progression is strongest in patients with adjuvant systemic therapy, particularly chemotherapy, and thus may reflect therapy resistance.

No significant financial relationships to disclose.