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PURPOSE Distant metastases are present in 6% or more of patients with newly diagnosed breast cancer. In this context, locoregional therapy for the intact primary tumor has been hypothesized to improve overall survival (OS), but clinical trials have reported conflicting results. METHODS Women presenting with metastatic breast cancer and an intact primary tumor received systemic therapy for 4-8 months; if no disease progression occurred, they were randomly assigned to locoregional therapy for the primary site (surgery and radiotherapy per standards for nonmetastatic disease) or continuing sysmetic therapy. The primary end point was OS; locoregional control and quality of life were secondary end points. The trial design provided 85% power to detect a 19.3% absolute difference in the 3-year OS rate in randomly assigned patients. The stratified log-rank test and Cox proportional hazards model were used to compare OS between arms. Cumulative incidence of locoregional progression was compared using Gray's test. Quality-of-life assessment used standard instruments. RESULTS Of 390 participants enrolled, 256 were randomly assigned: 131 to continued systemic therapy and 125 to early locoregional therapy. The 3-year OS was 67.9% without and 68.4% with early locoregional therapy (hazard ratio = 1.11; 90% CI, 0.82 to 1.52; P = .57). The median OS was 53.1 months (95% CI, 47.9 to not estimable) in the systemic therapy arm and 54.9 months (95% CI, 46.7 to not estimable) in the locoregional therapy arm. Locoregional progression was less frequent in those randomly assigned to locoregional therapy (3-year rate: 16.3% v 39.8%; P < .001). Quality-of-life measures were largely similar between arms. CONCLUSION Early locoregional therapy for the primary site did not improve survival in patients presenting with metastatic breast cancer. Although it was associated with improved locoregional control, this had no overall impact on quality of life.

LBA2 Background: About 6% of newly diagnosed breast cancer patients present with Stage IV disease and an intact primary tumor (IPT). Locoregional treatment (LRT) for the IPT is hypothesized to improve survival based on retrospective analyses, but randomized trials have provided conflicting data. We now report the results of E2108, a Phase 3 trial that examined the worth of LRT for the IPT following initial systemic therapy. Methods: Stage IV patients with IPT were registered, treated with optimal systemic therapy (OST) based on patient and tumor characteristics; those who did not progress during 4-8 months of OST were randomized to LRT for the IPT, or no LRT. The primary endpoint was overall survival (OS), with locoregional disease control as a secondary endpoint. Stratified log rank test and Cox proportional hazard model were used to compare OS between treatment groups. Cumulative incidence of locoregional recurrence/progression was estimated and Gray test was used for treatment group comparisons. The trial was designed to detect an improvement in 3 year OS rate from 30% with OST alone to 49.3% for OST+LRT (power 95%, 1-sided alpha 0.05) with full information expected after 152 deaths; the data monitoring committee recommended data release after 80% of full information. Results: 390 patients were enrolled between 2/8/11 and 7/23/15, and received OST. Of these, 256 eligible patients were randomized to either continued OST alone (N = 131) or OST+LRT (N = 125).There were 121 deaths and 43 locoregional progression events after a median follow up 59 months (range: 0-91). There was no significant difference in OS (3-year OS rate 68.4% in OST+LRT vs. 67.9% OST alone arm, stratified log-rank p = 0.63, HR = 1.09, 90% CI: 0.80, 1.49) or in progression-free survival (p = 0.40). The locoregional recurrence/progression was significantly higher in the OST alone arm (3-year rate 25.6% vs 10.2%, Gray test p = 0.003). Health-related quality of life (HRQOL) measured by FACT-B Trial Outcome Index was significantly worse in the OST+LRT arm than OST alone arm at 18 months post randomization (60% completion, Wilcoxon rank sum test p = 0.01), but no difference was observed at time points 6 months (74% completion) or 30 months (56% completion). Conclusions: Early local therapy does not improve survival in patients with de novo metastatic breast cancer and an IPT. Although there was a 2.5-fold higher risk of local disease progression without LRT, LRT of the IPT did not lead to improved HRQOL. Clinical trial information: NCT01242800 .

507 Background: The 21-gene Recurrence Score (OncotypeDX Breast Cancer Assay) predicts outcome and benefit from chemotherapy (CT) in early stage ER+ BC treated with adjuvant endocrine therapy. We evaluated the association between Recurrence Score (RS), time to progression (TTP), and overall survival (OS) in patients with stage IV BC enrolled in TBCRC 013. Methods: TBCRC 013 is a registry study evaluating surgery of the primary tumor in pts presenting with Stage IV BC. From 7/09 - 4/12, 128 evaluable pts were enrolled in two cohorts (A: metastases (mets) with intact primary tumor (n=112); B: mets within 3 months of primary surgery (n=16)). This study includes 110 pts with pre-treatment primary tumor samples available for analysis. Clinical variables, TTP and OS were correlated with RS using long-rank, Kaplan-Meier and Cox regression. Results: Median pt age was 52yrs (21-79) and median tumor size 3.1cm (0.7-15). 82 (80%) were ER+, 83 (81%) Her2(-) and 51 (46%) had bone-only mets. Cohorts A and B did not differ. At a median follow-up of 26 mos (1-47), median TTP is 19 mos (95%CI16-25) and surgery is not associated with OS. 102 samples qualified for RS. 23 (23%) had low RS<18, 29 (28%) intermediate RS, 18-30; and 50 (49%) high RS≥31. Age, tumor size or site of 1stmets was not associated with RS. Risk groups were prognostic for TTP in ER+ pts and for 2 yr OS in ER+Her2- pts (Table). In Cox models continuous RS was also prognostic for TTP in ER+ pts (HR 3.5; for 50 point difference (PD) 95%CI 1.5-8.1, p=0.003) and for OS in ER+Her2- pts (HR 21.4, for 50 PD 95%CI 2.2-204.4, p=0.008). In MVA, adjusting for clinical variables, RS remained prognostic for TTP in ER+ pts (p=0.01). Further analysis of surgery in this trial is ongoing. Conclusions: The 21-gene RS is independently prognostic for TTP in ER+ Stage IV BC. RS is also prognostic for OS in ER+Her2- BC, suggesting that a high RS may be a surrogate for endocrine resistance and could be used to select pts with ER+ Stage IV BC for CT. A randomized trial to address this hypothesis is warranted. Clinical trial information: NCT00941759. [Table: see text]

LBA513 Background: Neoadjuvant aromatase inhibitor (AI) therapy is a rational and effective approach to improving the breast conservation surgery (BCS) rate for postmenopausal patients with large, estrogen receptor (ER) rich breast cancers. Barriers to adopting this strategy include lack of experience in this management approach in the US and uncertainty regarding the comparative effectiveness of the three approved aromatase inhibitors for this indication. Methods: ACOSOG Z1031 is a multicenter, open-label, neoadjuvant phase III screening study that randomized postmenopausal women with clinical stage II/III ER rich (Allred score 6-8) breast cancer to 16 weeks of either exemestane (EXE) 25 mg daily, letrozole (LET) 2.5 mg daily, or anastrozole (ANA) 1 mg daily. At baseline study participants were either marginal for BCS (MBCS), candidates for mastectomy only (MO), or inoperable (IO). Planned enrolment was 125 patients per arm in order that the likelihood of the treatment with the “best” 16-week clinical response rate (based on caliper measurements) by WHO criteria (cRR) was included among the subset of treatments with “similar” cRR (90% power). Secondary endpoints included: extent of surgery, radiologic and pathologic response rates. Results: From 4/1/2006 to 10/1/2009, 377 postmenopausal women with clinical stage II or III ER rich breast cancer were enrolled. 374 women began treatment and were included in an intent-to-treat analysis. Median age was 66 yrs (range: 43-90 yrs), Median tumor size was 4.0 cm (range: 2-13 cm). The 16-week cRR was 60.5% (95%CI: 51.3-69.1%) for EXE; 70.9% (95% CI: 62.2-78.6%) for LET, and 66.7% (95% CI: 57.6-74.9%) for ANA. Seventeen patients did not have surgery due to refusal (12 pts), progression (3 pts) or other medical conditions (2 pts). The BCS rate was 78% (163/207) in MBCS group; 42% (77/163) in MO group; and 75% in IO group (3/4). Surgeons made the decisions regarding procedure choice 75% of the time in both the MBCS and the MO categories. Conclusions: This large multicenter screening trial selected non-steroidal AIs for further development due to their higher observed cRR. The study demonstrates that high response and breast conservation rates and low rates of disease progression can be achieved through patient selection based on high ER expression. We are currently refining our approach for early detection of poor response to AIs through an assessment of the tumor Ki67 proliferation index at 2 to 4 weeks (Z1031 Cohort B). [Table: see text]

Purpose To determine the pathologic complete response (pCR) rate in estrogen receptor (ER) –positive primary breast cancer triaged to chemotherapy when the protein encoded by the MKI67 gene (Ki67) level was > 10% after 2 to 4 weeks of neoadjuvant aromatase inhibitor (AI) therapy. A second objective was to examine risk of relapse using the Ki67-based Preoperative Endocrine Prognostic Index (PEPI). Methods The American College of Surgeons Oncology Group (ACOSOG) Z1031A trial enrolled postmenopausal women with stage II or III ER-positive (Allred score, 6 to 8) breast cancer whose treatment was randomly assigned to neoadjuvant AI therapy with anastrozole, exemestane, or letrozole. For the trial ACOSOG Z1031B, the protocol was amended to include a tumor Ki67 determination after 2 to 4 weeks of AI. If the Ki67 was > 10%, patients were switched to neoadjuvant chemotherapy. A pCR rate of > 20% was the predefined efficacy threshold. In patients who completed neoadjuvant AI, stratified Cox modeling was used to assess whether time to recurrence differed by PEPI = 0 score (T1 or T2, N0, Ki67 < 2.7%, ER Allred > 2) versus PEPI > 0 disease. Results Only two of the 35 patients in ACOSOG Z1031B who were switched to neoadjuvant chemotherapy experienced a pCR (5.7%; 95% CI, 0.7% to 19.1%). After 5.5 years of median follow-up, four (3.7%) of the 109 patients with a PEPI = 0 score relapsed versus 49 (14.4%) of 341 of patients with PEPI > 0 (recurrence hazard ratio [PEPI = 0 v PEPI > 0], 0.27; P = .014; 95% CI, 0.092 to 0.764). Conclusion Chemotherapy efficacy was lower than expected in ER-positive tumors exhibiting AI-resistant proliferation. The optimal therapy for these patients should be further investigated. For patients with PEPI = 0 disease, the relapse risk over 5 years was only 3.6% without chemotherapy, supporting the study of adjuvant endocrine monotherapy in this group. These Ki67 and PEPI triage approaches are being definitively studied in the ALTERNATE trial (Alternate Approaches for Clinical Stage II or III Estrogen Receptor Positive Breast Cancer Neoadjuvant Treatment in Postmenopausal Women: A Phase III Study; clinical trial information: NCT01953588).

Abstract Background: Neoadjuvant aromatase inhibitor (AI) therapy would become a more acceptable alternative to chemotherapy if there was a way to identify AI-resistant cases early for triage to alternate systemic treatment. We therefore conducted a Phase 2 trial of post-menopausal patients with clinical stage 2 or 3 ER+ (Allred Score 6 to 8) breast cancer who were re-biopsied 2 to 4 weeks after initiating neoadjuvant AI therapy. If the tumor Ki67 level was &gt; 10% (AI resistant) the patient was triaged to either chemotherapy or immediate surgery and if &lt; 10% (AI sensitive) the patient completed 16 to 18 weeks of neoadjuvant AI treatment. Co-primary endpoints were: 1) to confirm that the pathological complete response (pCR) rate to standard NCCN chemotherapy in the AI resistant population is in the range of 20% (similar to ER− disease). This required the observation of least 4/35 pCRs; 2) whether patients were willing to accept a recommendation of no chemotherapy when the preoperative endocrine prognostic index score was zero (PEPI-0) (pStage 1 or 2A, Ki67&lt;2.7% and ER+) since, according to the PEPI model, these patients have such a low relapse risk that chemotherapy is unlikely to be of value (Ellis, M JNCI 100:1380–8, 2008). Feasible was defined as &lt;10% PEPI-0 cases receiving adjuvant chemotherapy. Secondary endpoints included a determination of the distribution of intrinsic subtypes in the AI sensitive and resistant groups (using a research use only assay). Results: 51 patients (21%) had 2 to 4 week Ki67&gt;10%, of these 36 received chemotherapy per protocol (27) anthracycline (A) and taxane (T)-based, 7 T-based, 1 A-only based and 1 other (non-NCCN) regimen but only 2 patients had a pCR (5.5%). 194 patients (79%) had a Ki67 &lt;10%, of these 176 had PEPI score information. 65 had a PEPI-0 (37%), of which 61 (94%) reported a treatment plan that did not include adjuvant chemotherapy. The AI resistant group had a significantly higher frequency of baseline high-risk intrinsic subtypes (LumB: 26, HER2-E: 2 versus LumA: 7) at baseline than the AI sensitive group (LumB: 40, HER2-E: 0 versus LumA: 66) Fishers exact test p = 7.16E−6. Additional molecular data will be presented at the meeting. Conclusion. A Ki67 value &gt;10% at 2 to 4 weeks strongly enriches for high-risk molecular subtypes (mainly LumB) however standard neoadjuvant chemotherapy did not meet pre-assigned criteria for adequate Phase 2 activity in this group. Novel neoadjuvant approaches for AI resistant-disease defined by high on treatment Ki67 are therefore a high priority. Management of patients with excellent response to neoadjuvant endocrine therapy (PEPI-0) without adjuvant chemotherapy is feasible. The ALTERNATE trial will enroll over 2000 patients to establish a new standard of care for neoadjuvant treatment of ER+ HER2− disease based on these principles. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD07-01.

Abstract Background: Retrospective studies suggest that primary breast surgery is associated with improved overall survival (OS) in Stage IV breast cancer. TBCRC 013 is a multi-center prospective registry study evaluating the role of surgery for the primary tumor in Stage IV disease. Methods: From 7/09 - 4/12, 128 eligible pts from 14 sites were enrolled in two cohorts (A: Stage IV with intact primary tumor (n = 112); B: metastases (mets) within 3 months of primary surgery (n = 16)). Baseline patient and tumor characteristics, and surgery of the primary were correlated with 2yr overall survival (OS) using log rank, Kaplan Meier and Cox regression for all patients. Comparisons were also made between cohorts A and B and within cohort A stratified by response to systemic therapy. Responders included those with any response (partial,complete) or stable disease at distant sites. Results: Median pt age was 52yrs(21-79) and median primary tumor size 3.2cm(0.7-15). Phenotypes were ER+ 106 (83%), HER2neg 91(71%), and triple neg 10(8%). 60(47%) had bone-only mets. The only significant baseline difference between cohorts A and B was the presence of palpable nodes (A:62% vs B:0%, p&lt;0.001). There were no differences in age, tumor size, ECOG scores, ER or HER2 status, number or sites of mets between cohorts A and B. At a median follow-up of 25 mo (95%CI, 23-31), 2yr OS for all pts is 86% (80-92) and is superior in cohort B as compared to A, (100% vs 84%, p = 0.03). On multivariate analysis (MVA) including all pts, only surgery, ER and HER2 positivity were associated with improved OS (table). Among 112 pts with an intact primary (Arm A), 17(15%) were non-responsive (NR) to systemic therapy, 3(18%) of whom required palliative surgery at a median time of 10.4mos. 2yr OS among NR was 33% (15-69) as compared to 94% (88-99) in Arm A responders (R) (p&lt;0.001). ER positivity was the only baseline difference between NR (65%) and R (88%) within Arm A (p = 0.02). Among 94(85%) Arm A responders, 39(41%) had elective surgery (median 8.4 mos, 95%CI:6.9-10.3) and only 1 of the remaining 47(2%) required palliation. When limited to Arm A responders, elective surgery was not associated with improved 2yr OS (surgery vs not: 94% vs 92%, p = 0.5). Median time to progression following elective surgery was 12 mos (95%CI,8-19mos). When cohort B (n = 16) and cohort A surgery groups (n = 39) are combined, surgery of the primary tumor is associated with improved 2yr OS (96% vs 74%, p = 0.002). Conclusions: In this prospective registry study, patients diagnosed with mets within 3 months of primary breast surgery have an improved 2yr OS. When all pts having surgery (A + B) are examined, surgery is associated with improved OS on MVA, but when limited to Arm A responders, elective surgery does not improve OS. Given that the number of Arm A responders is small, results from the prospective randomized trial will be needed to address this question. These data also demonstrate that the need for surgical palliation of the primary tumor is uncommon in the modern era. Multivariate Analysis for OSN = 128HR Death (95%CI)pvalueSurgery0.28 (0.10-0.74)0.01ER positivity0.28 (0.10-0.72)0.01HER2 positivity0.21 (0.06-0.74)0.01MVA included: age, tumor size, ECOG, ER, PR, HER2, met sites, and surgery Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-09.

Abstract Background: Estrogen receptors are over-expressed in around 70% of breast cancer cases. The genetic changes that occur during aromatase inhibitor (AI) treatment are not well understood and may differ depending upon the patient's response phenotype. Methods: We performed whole genome sequencing (WGS) of matched blood, pre-treatment, and post-treatment biopsy samples from 22 estrogen receptor positive breast cancer patients treated with neoadjuvant aromatase inhibitors. For 5 cases, we performed the whole genome sequencing (WGS) on patients’ matched normal, two pre AI-treatment, and two post AI-treatment DNA isolates from biopsy samples. We validated all putative coding and non-coding somatic mutations using deep sequencing. By comparing the validated somatic mutations from pre- and post- AI treatment biopsy samples, we were able to determine the alterations in the tumor genomes. In every case we defined the clonal architecture of each pair of pre-treatment and post-treatment biopsy samples by comparing the variant allele frequencies from thousands of validated somatic mutations. Results: Comparisons of the two pre AI-treatment biopsy samples from the same patient indicates that the variant allele frequencies of mutations showed high concordances in all 5 cases, 0.74 to 0.95 range of correlation coefficient. Only a small percentage of somatic mutations were detected in one pre-treatment sample and not the other (4.65% overall). In comparing the somatic variations between pre-treatment and matched post-treatment biopsy samples in 22 cases, we found that patients with good clinical response to AI treatment retained known driver mutations only in their pre-treatment tumors. Conversely, those patients with poor clinical response presented new driver mutations in their post-treatment samples. Furthermore, the variant allele frequency for most mutated genes decreased in post AI treatment samples for patients with good AI treatment response; on the contrary, the variant allele frequency increased for patients with poor clinical response. Conclusions: From WGS of matched normal, pre-treatment, and post-treatment biopsy samples, we identified new driver genes mutated in patients with poor clinical response, while patients with good clinical response had lost mutated driver genes in their post-treatment biopsy samples. The genetic landscape revealed by WGS of pre-treatment and post-treatment biopsy samples reveals mutational repertoires are remodeled by AI therapy. This finding suggests deep sequencing of AI treated samples will be necessary to reveal the complete complement of mutations present in a patient's tumor. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-423. doi:1538-7445.AM2012-LB-423

Purpose Preoperative aromatase inhibitor (AI) treatment promotes breast-conserving surgery (BCS) for estrogen receptor (ER) –positive breast cancer. To study this treatment option, responses to three AIs were compared in a randomized phase II neoadjuvant trial designed to select agents for phase III investigations. Patients and Methods Three hundred seventy-seven postmenopausal women with clinical stage II to III ER-positive (Allred score 6-8) breast cancer were randomly assigned to receive neoadjuvant exemestane, letrozole, or anastrozole. The primary end point was clinical response. Secondary end points included BCS, Ki67 proliferation marker changes, the Preoperative Endocrine Prognostic Index (PEPI), and PAM50-based intrinsic subtype analysis. Results On the basis of clinical response rates, letrozole and anastrozole were selected for further investigation; however, no other differences in surgical outcome, PEPI score, or Ki67 suppression were detected. The BCS rate for mastectomy-only patients at presentation was 51%. PAM50 analysis identified AI-unresponsive nonluminal subtypes (human epidermal growth factor receptor 2 enriched or basal-like) in 3.3% of patients. Clinical response and surgical outcomes were similar in luminal A (LumA) versus luminal B tumors; however, a PEPI of 0 (best prognostic group) was highest in the LumA subset (27.1% v 10.7%; P = .004). Conclusion Neoadjuvant AI treatment markedly improved surgical outcomes. Ki67 and PEPI data demonstrated that the three agents tested are biologically equivalent and therefore likely to have similar adjuvant activities. LumA tumors were more likely to have favorable biomarker characteristics after treatment; however, occasional paradoxical increases in Ki67 (12% of tumors with > 5% increase after therapy) suggest treatment-resistant cells, present in some LumA tumors, can be detected by post-treatment profiling.