Citations

Abstract Background: We had previously reported after a median followup of 5.3 years that disease free survival (DFS) was improved with either adjuvant weekly paclitaxel (hazard ratio [HR] 0.73, p=0.0006) or every 3 week docetaxel (HR 0.77, p=0.02) compared with every 3 week paclitaxel (N Eng J Med 2008; 358; 1663), and that obesity and black race were independently associated with inferior outcomes in estrogen receptor (ER)-positive disease after a longer followup (Cancer 2012: 118: 5937 & JNCI 2012; 104: 406). We now report updated results after a median followup of 12.1 years. Methods: Eligibility included axillary lymph node positive or high-risk (tumor at least 2 cm) node-negative breast cancer. All patients received 4 cycles of AC (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2) every 3 weeks, followed by either: (1) paclitaxel 175 mg/m2 every 3 weeks x 4 (P3), (2) paclitaxel 80 mg/m2 weekly x 12 (P1), (3) docetaxel 100 mg/m2 every 3 weeks x 4 (D3), or (4) docetaxel 35 mg/m2 weekly x 12 (D1). Patients with ER-positive breast cancer also received endocrine therapy for at least 5 years, including either tamoxifen and/or an aromatase inhibitor. The primary comparisons included taxane (P vs. D) and schedule (every 3 weeks vs. weekly), and the primary endpoint was DFS, defined as local, regional, and/or distant relapse, second primary breast cancer, or death without recurrence. Results: A total of 4954 eligible patients were accrued between October 1999 and January 2002. At the time of this analysis, 90% of surviving patients were followed for at least 10 years, and there were substantially more DFS events (1639 vs. 1048) and deaths (1283 vs. 686) than the original report. For the primary comparison, there remains no significant difference in DFS by taxane (p=0.33) or schedule (p=0.88), although there was a significant interaction between taxane and schedule (p<0.007). When comparing the standard arm (P3) to the other arms (with a hazard ratio [HR] < 1 favoring the experimental arms using a stratified Cox model), the HRs for DFS were 0.84 (p = 0.011) for arm P1 and 0.79 (p=0.001) for arm D3 arm, and for overall survival (OS) were 0.87 (p=0.09) and 0.86 (p=0.054), respectively. When evaluated by subtypes in exploratory analyses, the P1 arm (but not the D3 arm) was associated with improved DFS (HR 0.69, p=0.01) and OS (HR 0.69, p=0.019) in the 1025 patients with triple negative breast cancer (TNBC), and the D3 arm (but not P1 arm) was associated with improved DFS (HR 0.76, p=0.004) but not OS (HR 0.87, p=0.20) in the 2785 patients with ER-positive, HER2-negative/unknown breast cancer (ERBC). In ERBC but not other subtypes, black race (HR 1.60, p=0.002) and obesity (HR 1.23, p=0.009) were associated with inferior OS, and obesity was associated with a higher recurrence risk between 3-8 years after diagnosis. Conclusions: Improvements in DFS observed at 10 years for the P1 and D3 arms compared with the P3 arm are qualitatively similar but quantitatively less than at 5 years, and the effects on OS are marginal in the overall population. The relative effectiveness of weekly paclitaxel and every 3 week docetaxel may vary by subtype. Citation Format: Joseph A Sparano, Fengmin Zhao, Silvana Martino, Jennifer Ligibel, Thomas Saphner, Antonio C Wolff, George W Sledge Jr, Edith A Perez, William C Wood, Nancy E Davidson. Ten year update of E1199: Phase III study of doxorubicin-cyclophosphamide followed by paclitaxel or docetaxel given every 3 weeks or weekly in patients with axillary node-positive or high-risk node-negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S3-03.

Abstract Background: Preclinical and clinical data indicate a key role for the PI3-kinase (PI3K) pathway in the pathogenesis of resistance to endocrine therapies in hormone receptor-positive (HR) breast cancer (BC) and suggest that combining PI3K inhibitors with endocrine therapy may partially overcome this resistance. FERGI is the first randomized Phase II study testing pictilisib (GDC-0941), a PI3K inhibitor, in combination with fulvestrant to evaluate this hypothesis in MBC patients with and without PIK3CA-mutant tumors. Methods: 168 post-menopausal pts with ER-positive, HER2-negative MBC were randomized (1:1) to receive fulvestrant with either pictilisib 340 mg QD (n=89, "combination" arm) or matching placebo (n=79, "control" arm). To be eligible, pts had to have relapsed during or within 6 mos of completing adjuvant AI treatment or have progressed on an AI for MBC. Pts were stratified based on tumor PIK3CA mutation status, resistance to prior AI therapy and presence of measurable disease. The primary endpoint was PFS by investigator assessment in the intent-to-treat (ITT) group and in pts with centrally confirmed PIK3CA-mutant tumors. The primary analysis was based on a 6 mo median duration follow up. Results: Baseline disease and prior treatment characteristics were similar between study arms. Observed treatment-emergent AEs were consistent with those previously described for single agent pictilisib and fulvestrant (primary toxicities were rash and GI disorders). In the ITT population (84 events) the median PFS (mPFS) was 6.2 mo in the combination arm vs 3.8 months for the control arm (HR, 0.77; 95% CI, 0.50-1.19). For pts with PIK3CA-mutant tumors (37 events), mPFS was 6.2 mo in the combination arm vs 5.1 mo in the control arm (HR, 0.92; 95% CI, 0.48-1.76). For pts without a detectable PIK3CA mutant tumor (43 events), mPFS was 5.8 months in the combination arm vs 3.6 months in the control arm (HR, 0.64; 95% CI, 0.35-1.17). Exploratory post-hoc subgroup analysis suggested improvement in PFS in pts with ER+ and PR+ tumors (centrally confirmed) treated with pictilisib plus fulvestrant. In the ER+/PR+ subgroup (57 events) mPFS was 7.2 mo in the combination arm vs 3.7 mo in the control arm (HR, 0.46; 95% CI, 0.27 to 0.78). This improvement was independent of tumor PIK3CA mutation status. Multivariate analysis suggests that this treatment effect in pts with ER+/PR+ tumors is maintained after adjusting for possible baseline imbalances. A similar analysis on pts with luminal A tumors (per PAM50 analysis) was also consistent with the findings in pts ER+/PR+ disease. Conclusions: This is the first report of a blinded, randomized clinical study evaluating a PI3K inhibitor in pts with MBC. In the ITT population, the addition of pictilisib to fulvestrant was associated with a mPFS improvement of 3.8 mo to 6.2 mo. Exploratory subgroup analyses suggested in pts with ER+/PR+ tumors are more likely to derive benefit from the addition of pictilisib to fulvestrant irrespective of PIK3CA mutation status, though the subgroup analyses are limited by the sample size. Additional biomarker analyses will be reported. Citation Format: Ian Krop, Stephen Johnston, Ingrid A Mayer, Maura Dickler, Vinod Ganju, Andres Forero-Torres, Bohuslav Melichar, Serafin Morales, Richard de Boer, Steven Gendreau, Mika Derynck, Mark Lackner, Jill Spoerke, Ru-Fang Yeh, Gallia Levy, Vivian Ng, Carol O'Brien, Heidi Savage, Yuanyuan Xiao, Timothy Wilson, Soo Chin Lee, Katarina Petrakova, Susanne Vallentin, Denise Yardley, Matthew Ellis, Martine Piccart, Edith A Perez, Eric Winer, Peter Schmid. The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S2-02.

Abstract Background: Tumor-infiltrating lymphocytes (TILs) at diagnosis are reported to be prognostic in triple-negative breast cancer (BC). Analysis of a small subset of 209 HER2+ patients (pts) with 49 events concluded that higher levels of S-TILs are associated with increased trastuzumab benefit (Loi, 2014). Here we report the largest study to date evaluating S-TILs and their prognostic and predictive association with clinical outcome in N9831 pts treated with either chemotherapy or chemotherapy plus trastuzumab. Methods: Samples assessed were from primary tumors of pts on N9831 arm A (standard AC→T chemotherapy) and arm C (concurrent chemotherapy with trastuzumab) (Perez, 2011). S-TILs were evaluated on H&E whole tumor slides by a single pathologist with ∼10% of cases read by two pathologists in tandem. The percent of stromal lymphocytic infiltrates (S-TILs) was quantitated in deciles; ≥60% S-TILs was used for the categorical cutoff (Denkert, 2010). The association between S-TILs, treatment (tx) and recurrence-free survival (RFS) was studied and the interaction between S-TILs, trastuzumab benefit and RFS was calculated. Results: 489 pts from arm A (chemo) and 456 pts from arm C (chemo with trastuzumab) were assessed and were similar to pts in the overall trial; all had RFS information and a median follow-up of 4.4yr. Tumors from 54% of pts in arms A and C were HR+; 14% were node-negative. Tumors with high S-TILs were more likely to be hormone receptor-negative (p< 0.0001). In multivariable analyses including nodal status, hormone receptor status, tx arm, tumor size, tumor grade, and age, ≥60% S-TILs was significantly associated with RFS (HR 0.20; 95%CI 0.064–0.65, p=0.007) in arm A but not in arm C (HR 1.1; 95%CI 0.42–2.8, p=0.87); the interaction term of arm and ≥60% S-TILs was significant (p=0.042). Semi-continuous deciles were associated with RFS in arm A (p<0.0002) but not in C (p=0.37). Hormone receptor status was an independent prognostic factor in arm A (HR 0.61; 95%CI 0.41-0.93, p=0.02) but not in C (HR 0.79; 95%CI 0.44-1.41, p=0.42). In arm A the 10yr Kaplan-Meier estimates for RFS were 90.9% and 64.5% for high S-TILs and low S-TILs pts, respectively (HR 0.23; 95%CI 0.073–0.73, p=0.013). In arm C the 10yr Kaplan-Meier estimates for RFS were 80.0% and 80.1% for high S-TILs and low S-TILs pts, respectively (HR 1.26; 95%CI 0.5–3.2, p=0.63). Arm A (N=489)Arm C (N=456)VariableHR (95% CI)p-valueHR (95% CI)p-valueNodal statusLymph node(-)1.00 (ref)<0.00011.00 (ref)0.0131-3+0.58 (0.25, 1.35) 2.99 (0.40, 22.70) 4-91.46 (0.64, 3.35) 3.29 (0.42, 25.80) 10+2.42 (1.04, 5.64) 8.22 (1.06, 63.60) HR statusnegative1.00 (ref)0.01981.00 (ref)0.42positive0.61 (0.41, 0.93) 0.79 (0.44, 1.41) S-TILs status<60%1.00 (ref)0.0071.00 (ref)0.87≥60%0.2 (0.06, 0.65) 1.08 (0.42, 2.79) Tumor gradeGrade 1 or 21.00 (ref)0.501.00 (ref)0.51Grade 31.18 (0.73, 1.91) 1.24 (0.65, 2.39) Tumor size1.08 (0.98, 1.19)0.121.00 (0.93, 1.07)0.92Age0.99 (0.97, 1.00)0.131 (0.98, 1.03)0.87 Conclusions: In exploratory analyses from this subset HER2+ population from N9831, S-TILs were associated with RFS in patients treated with chemotherapy alone, and were not shown to be associated with RFS in patients treated with chemotherapy plus trastuzumab. Citation Format: Edith A Perez, Karla V Ballman, S Keith Anderson, E Aubrey Thompson, Sunil S Badve, Helen Bailey, Frederick L Baehner. Stromal tumor-infiltrating lymphocytes(S-TILs): In the alliance N9831 trial S-TILs are associated with chemotherapy benefit but not associated with trastuzumab benefit [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S1-06.

Abstract Background. We recently identified an in-frame ESR1 translocation in a tumor and PDX pair from a patient with endocrine therapy resistant advanced disease. The fusion gene preserved the N-terminal 365aa of ESR1 containing the intact activation function 1 (AF1), DNA-binding domain (DBD) and hinge, followed by the C-terminal transactivation domain of YAP1. The ESR1-365>YAP1 fusion drove estrogen-independent and anti-estrogen-resistant tumor cell growth (Cell Reports 4:1116, 2013). We therefore sought to further investigate the role of ESR1 fusion genes in breast cancer. Methods. 711 cases from TCGA, 82 ER+ cases from neoadjuvant endocrine therapy trials and 25 ER+ systemic relapse samples were screened for fusion genes using RNAseq. Fusion genes involving ESR1 were subsequently assayed for estrogen response element (ERE)-mediated transcriptional activity and ability to drive estradiol independent breast cancer cell growth. Results. Multiple ESR1 fusions were identified in mostly luminal B cancers. ESR1 fusions resulted most frequently from rearrangements involving another gene on Chromosome (Chr) 6 but also fusions with genes on other chromosomes. The fusions involving partners on Chr6 that retained an intact N terminal AF1 and DNA binding domain (DBD) of ESR1 (≥1-253aa) included an Out-of-Frame (OF) fusion event with CCDC170 (a gene immediately centromeric to ESR1), POLH (in-frame or IF), AKAP12 (IF), PCMT1 (OF), SYNE1 (OF) and GPR126 (OF). Also identified were inter-chromosomal translocations involving Chr12p-NOP2 (IF) and ChrX-PCDH11X (IF) and Chr7q-AKR1D1 (OF). The ESR1 fusions with transcriptional potential (because of a retained DNA binding domain) included variable 5’ ESR1 exons that preserved 253aa, 365aa, 412aa or 458aa of ESR1 sequence: in all cases disrupting ligand binding though loss of C terminal sequence. The effect of the IF and OF 3’ sequences on the transcriptional activity of the relevant ESR1 fragment was highly variable. The most transcriptionally active fusion (more active than the relevant ESR1 fragment alone) was the ESR1-365>YAP1 as well as ESR1-365>PCDH11X and ESR1-253>CCDC170. This is remarkable since PCDH11X is not considered a transcription factor and the CCDC170 sequence was OF – in both cases suggesting the activity of the fusion was due to "neomorphic" properties. Two fusions, NOP2 and POLH were inactive in the ERE reporter assay, yet both stimulated estradiol independent growth. In these cases we suggest that the ESR1 locus can function as a "promoter trap" which allows the identification of genes with previously unknown functions in endocrine therapy resistance. Conclusions: In luminal-type breast cancer the ESR1 gene was fused to multiple 3’ partners with remarkably heterogeneous functions. The two most transcriptionally active, ESR1-365>YAP1 and ESR1-365>PCDH11X, were both identified in endocrine therapy refractory advanced disease – suggesting a role in fatal disease progression. Citation Format: Jieya Shao, Jin Zhang, Robert J Crowder, Rodrigo Goncalves, Chanpheng Phommaly, Breast AWG and Network, Charles M Perou, Christopher A Maher, E Aubrey Thompson, Matthew J Ellis. ESR1 gene fusions implicated in endocrine therapy resistance of ER+ breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD6-4.

Abstract Background: Although the spectrum of genomic alterations in primary, treatment-naïve breast tumors has been described, the genomic landscape of HER2+ MBC remains underexplored. Furthermore, tumor genomic alterations that arise after progression on anti-HER2 therapy are largely unknown. Methods: We prospectively collected metastatic tumor biopsies from patients (pts) enrolled on TBCRC003 (NCT00470704), a phase II study evaluating the combination of lapatinib (L) and T in pts with HER2+ MBC who had varying degrees of prior T exposure. We performed WES on baseline metastatic biopsies and normal DNA from 57 pts. In 36 pts, we also performed WES on pre-treatment primary tumors. Tumors were analyzed for point mutations, insertions/deletions, and copy number alterations. Results: Total accrual was 116 pts. 87 pts were registered in one of two efficacy cohorts: Cohort 1 included pts w no prior T for MBC. Pts with prior adjuvant T were included if the interval from last T to 1st recurrence > 12 months. Cohort 2 included pts with 1-2 prior lines of T for MBC or recurrence within 12 months of adjuvant T. An additional 29 pts were enrolled in a biomarker cohort (Cohort 3). Per-protocol efficacy analyses for 85 pts deemed evaluable are shown below: Objective Response RateClinical Benefit RateMedian Time to ProgressionCohort 150% (90% CI 33.8-66.2%)57.5% (95% CI 40.9-73.0)7.4 monthsCohort 222.2% (90% CI 11.2-37.1%)42.2% (95% CI 27.7-57.8)5.3 months As we previously reported (Wagle et al, ASCO 2014), across 57 metastatic tumors, significant recurrently mutated genes were TP53 (n=30; 53%) and PIK3CA (n=19; 33%). The frequency of mutant TP53 and PIK3CA was not significantly different from 119 primary, treatment-naïve HER2+ tumors sequenced in the TCGA study (50%, p=0.8 and 27%, p=0.5, respectively). Recurrent copy number alterations were also similar to TCGA data. Comparing the 38 pts who received any prior T with the 19 pts who did not, there was no significant difference in the incidence of mutant TP53 (53% vs 53%, p=1.0) and PIK3CA (37% vs 26%, p=0.6). We identified mutations in the HER2 kinase domain in 4/38 pts who received prior T (11%), as compared to 0/19 T-naïve pts. HER2 kinase domain mutations have been identified in ∼2% of HER2-negative cancers but <1% of primary HER2+ cancers. 3 of the mutations were L755S, which has been shown to be resistant to L and sensitive to irreversible HER2 inhibitors. The 4th mutation was D742N, a novel kinase domain mutation. None of the 4 pts with HER2 kinase domain mutations had an objective response, though 1 pt had stable disease for 29 weeks. An analysis comparing paired archival primary tumors and baseline metastatic biopsies from 36 pts to identify genomic alterations acquired or enriched in the metastatic tumors will be presented. Conclusions: We present an analysis of the genomic landscape of HER2+ MBC, including comparisons between matched primary tumors and metastatic biopsies. Somatic HER2 kinase mutations in pts with HER2+ MBC treated with prior T suggests that these mutations may be involved in resistance to T, and may predict poor response to additional anti-HER2 therapy with combined L and T. Novel therapeutic approaches may be required for these pts. Citation Format: Nikhil Wagle, Nancy U Lin, Andrea L Richardson, Ignaty Leshchiner, Ingrid A Mayer, Andres Forero-Torres, Timothy J Hobday, Elizabeth C Dees, Rita Nanda, Mothaffar F Rimawi, Hao Guo, William T Barry, Ron Bose, Wei Shen, Antonio C Wolff, Stacey B Gabriel, Levi A Garraway, Eric P Winer, Ian E Krop. Whole exome sequencing (WES) of HER2+ metastatic breast cancer (MBC) from patients with or without prior trastuzumab (T): A correlative analysis of TBCRC003 [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD3-5.

Abstract Background Cancer genomic investigations have identified recurrent genomic aberrations critical for cancer initiation, progression, and metastases. However, these investigations are typically performed in isolation, and the effects of treatment on the clonal selection of tumor cells are mostly unknown. We hypothesized that molecular profiling of residual tumors after neoadjuvant chemotherapy (NAC) would identify new drug targets/pathways in patients at high risk for disease recurrence. To better identify clonal populations of resistant breast cancer cells, we utilized DNA content-based flow sorting of nuclei to identify and isolate clonal populations for aCGH and next generation sequencing (NGS) both before and after NAC. Methods The Breast Cancer Genome Guided Therapy Study (BEAUTY) (NCT 02022202) is a prospective study of patients with high-risk breast cancer treated with neoadjuvant 12 weekly paclitaxel (T) +/- trastuzumab followed by 4 cycles of anthracycline based chemotherapy. Tumor tissue from baseline, residual disease from surgery, distant metastases, and patient derived xenografts (PDX) are obtained for cell sorting by DNA ploidy, aCGH, RNA and exome sequencing. Results: 140 patients have been enrolled, 104 have completed surgery and 30 unique PDX have been established corresponding to 26 patients prior to chemotherapy and 4 from residual disease at surgery. Baseline exome and RNA sequencing is complete in 140. Currently, genomic analyses of flow sorted matched baseline, surgical, PDX, and distant disease samples are available in 6 patients. Substantial genomic variation was observed in the surgical sample compared to the primary tumor including gain of oncogenic drivers (EGFR) and loss of negative regulators (ATG5) (Table). The PDX recapitulated these events with excellent fidelity compared to the corresponding human tumor. In patients with TNBC, RNA seq obained from matched samples demonstrated changes in immune related pathways. Evaluation of drug targets/pathways identified in the resistant tumors are ongoing using the PDX and sequencing of the remaining matched baseline/surgical disease will be reported. Clonal changes occurring over time in patients with residual disease or disease recurrence after NACTumor SubtypeResidual Cancer BurdenDisease StatusClonal Aberration Changes (baseline and post NAC)TNBC (AR subtype)3Contralateral lymph node recurrence at 150 days2p25.2 - p25.1 amplicon lost at recurrence; 6p21.32 -p21.31 amplicon lost at recurrenceTNBC (BL 1)3Bone/liver/lymph node recurrence at 135 days5q11.2 amplicon gained at surgery; 12p13.33 - p13.2 amplicon gained at surgeryTNBC (BL 1)3Disease-free at day 1506q21 amplicon lost at sugeryTNBC (BL 2)0Brain recurrence at 390 daysChr 2 chromothripsis at surgeryLuminal B3Progression during chemotherapy7p12.1 - p11.2 amplicon gained at surgeryLuminal HER23Disease-free at day 3609q33.2 amplicon lost at surgery; 15q13.1 - q13.3 amplicon lost at surgery; 15q22.2 - q24.1 amplicon lost at surgery Conclusions: We observed substantial evolutionary changes in residual breast tumors remaining after NAC. Our findings suggest that a comprehensive assessment of the mutational landscape that has evolved during NAC can inform drug development in high risk breast cancer patients. Citation Format: Matthew P Goetz, Michael T Barrett, Krishna R Kalari, Vera J Suman, Sarah A McLaughlin, Alvaro Moreno-Aspitia, Ann M Moyer, Donald W Northfelt, Richard J Gray, Jason Sinnwell, Douglas Mahoney, Poulami Barman, Peter Vedell, Xiaojia Tang, Kevin Thompson, Travis Dockter, Katie Jones, Sara J Felten, Amy Conners, Jeanette Eckel-Passow, Hughes Sicotte, Steven N Hart, Jia Yu, Daniel W Visscher, Eric D Wieben, Cloann Schultz, Minetta C Liu, James N Ingle, Liewei Wang, Richard W Weinshilboum, Judy C Boughey. Impact of neoadjuvant chemotherapy on the clonal composition of breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD3-3.

Abstract Background: The ECOG E5194 study was a prospective trial designed to evaluate surgical excision (lumpectomy) without radiation for selected women with ductal carcinoma in situ (DCIS) of the breast with low risk clinical and pathologic features. Methods: Eligible patients were enrolled on two study cohorts (not randomized): (1) low or intermediate grade DCIS, tumor size < 2.5 cm; or (2) high grade DCIS, tumor size < 1.0 cm. Cohort assignment was based on pathology assessment from the treating institution. Protocol specifications included surgical excision of the DCIS tumor with a minimum negative margin width of at least 3 mm or no tumor on re-excision. Radiation treatment was not allowed. From April 1997 to October 2002, 665 evaluable patients were enrolled through ECOG or NCCTG (561 in Cohort 1; 104 in Cohort 2). Tamoxifen was optional (not randomized) beginning in May 2000, and was given to 30% of the patients. The primary study endpoint was the rate of developing an ipsilateral breast event (IBE), defined as local recurrence of DCIS or invasive carcinoma in the treated breast. The median follow-up was 12.3 years. We have previously reported 7-year results (L. Hughes, J Clin Oncol 27:5319, 2009; median follow-up 6.3 years; 66 IBE’s), and we herein provide 12-year results. Results: Median patient age was 60 years and 58 years for Cohort 1 and Cohort 2, respectively. Tumor size was < 10 mm for 79% and 80% of patients, respectively. The minimum negative margin width was > 5 mm for 64% and 69% of patients, respectively. There were 99 IBE’s, of which 51 (52%) were an invasive IBE. The IBE and invasive IBE rates increased over time in both cohorts (see Table). The 12-year rates of an IBE were 14.4% for Cohort 1 and 24.6% for Cohort 2 (p = 0.003), and for an invasive IBE, 7.5% and 13.4%, respectively (p = 0.08). No difference was seen for the 12-year rates of overall survival (84.0% vs 82.8%; p = .96) or contralateral breast events (6.7% vs 12.0%; p = 0.16). On multivariate analysis, study cohort (hazard ratio = 1.81; p = 0.01) and tumor size (p = 0.01) were statistically significant for an IBE, and study cohort was borderline statistically significant for an invasive IBE (p = 0.08). On central pathology review (75% of cases), neither grade nor comedo necrosis was associated with the risk of an IBE or invasive IBE (all p > 0.15). Salvage treatment at the time of an IBE included mastectomy for 42% (31/74) and 64% (16/25) of the patients, respectively. Conclusions: For these selected patients with favorable DCIS based on clinical and pathologic characteristics treated with surgical excision without radiation, the rates of an IBE and an invasive IBE continued to increase through at least 12 years of follow-up. IBE Rates According To Study Cohort. Cohort 1 (Low or Intermediate Grade)Cohort 2 (High Grade)TimeIBEInvasive IBEIBEInvasive IBEAt 5 years6.0% (4.0%, 8.1%)2.7% (1.3%, 4.1%)15.0% (7.7%, 21.7%)5.3% (0.8%, 9.7%)At 7 years9.5% (7.0%, 12.0%)4.8% (2.9%, 6.6%)18.2% (10.6%, 25.8%)7.6% (2.2%, 13.0%)At 10 years12.5% (9.5%, 15.4%)6.4% (4.2%, 8.6%)24.6% (15.7%, 33.4%)13.4% (5.9%, 20.9%)At 12 years14.4% (11.2%, 17.6%)7.5% (5.1%, 10.0%)24.6% (15.7%, 33.4%)13.4% (5.9%, 20.9%) Citation Format: Lawrence J Solin, Robert Gray, Lorie L Hughes, William C Wood, Mary Ann Lowen, Sunil Badve, Frederick L Baehner, James N Ingle, Edith A Perez, Abram Recht, Joseph Sparano, Kathy Miller, Nancy E Davidson. Local excision without radiation for ductal carcinoma in situ: 12-year results from the ECOG E5194 study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-13-01.

Abstract Background: Mammographic breast density (MBD) reflects the proportion of fibroglandular tissue in the breast, and is an established risk factor for breast cancer. Benign breast disease (BBD) is also a known risk factor for breast cancer. We previously showed an association between lobular involution (physiologic atrophy) and MBD in a large cohort study of women with BBD. We performed a comprehensive evaluation of the association of histologic features of BBD with MBD. Methods: The Mayo BBD cohort includes women, 18 to 85 years, who were diagnosed with BBD at Mayo Clinic in Rochester, MN between 01/01/1967 and 12/31/1991. For this study, we included women who had a mammogram within 6 months of BBD diagnosis, and diagnosed with BBD between 1985 and 1991 when parenchymal pattern of breast density was clinically recorded. Risk factor information such as age, and body mass index (BMI) was collected from medical records. Parenchymal pattern, assessed clinically and previously used in multiple studies of MBD and risk, classified breast density based on extent and type of density, into four categories: N1 (non-dense, no ducts visible); P1 (ductal prominence occupying <25% breast); P2 (prominent ductal pattern occupying >25% of the breast; DY (homogenous plaque-like areas of density). All assessments of benign breast tissue were performed by expert breast pathologists blinded to both MBD and BBD reports. Histologic characteristics included overall impression (non-proliferative disease (NPD), proliferative disease without atypia (PDWA), and atypical hyperplasia (AH)), proportion of normal lobules that were involuted (no (0%), partial (1 to 74%), or complete (≥75%)), type of AH (ADH or ALH), ductal and lobular hyperplasia, calcifications, sclerosing adenosis, columnar alteration, cyst, fibroadenoma, marked fibrosis, intra-ductal papilloma, radial scar (number and size), duct ectasia, and mucocele like tumors. Associations of parenchymal pattern with BBD characteristics were examined using multicategorical nominal logistic regression models. We first examined associations after adjustment for age and BMI. All variables statistically significant (p<0.05) in these models were then simultaneously included in a fully-adjusted model. Results: Of 2,257 women in the study, 14% were <40 years old, 52.7% between 40- 59 years, and 32.9% were ≥60 years. In this sample, 55.2% of women had NPD, 36% had PDWA, and AH in 8.8%. MBD was classified as N1 in 21.8%, P1 in 12.6%, P2 in 23.7% and DY in 41.9%. Age- and BMI-adjusted analyses showed that there was an association of parenchymal pattern with overall impression, lobular involution, ductal hyperplasia, sclerosing adenosis, columnar alteration, cyst, duct ectasia and fibrosis. Multivariate analyses found that women of younger age (p<0.001) and with lower BMI (p<0.001), presence of fibrosis (p<0.001) and no involution (p=0.016) were more likely to have P2 or DY parenchymal pattern than women without those characteristics. Conclusion: Among women with benign breast disease, higher MBD is associated with younger age, lower BMI, fibrosis, and lack of lobular involution. These findings, concordant with other studies of MBD, provide insight into underlying mechanisms by which MBD and BBD contribute to breast cancer risk. Citation Format: Karthik Ghosh, Robert A Vierkant, Ryan D Frank, Daniel W Visscher, Vernon S Pankratz, Christopher G Scott, Derek C Radisky, Marlene H Frost, Lynn C Hartmann, Amy C Degnim, Celine M Vachon. Association between mammographic breast density and histologic features of benign breast disease [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-14.

Abstract Introduction: Current models to predict breast cancer risk do not differentiate risk for estrogen receptor (ER) positive and negative breast cancer (BC), despite growing evidence that these tumors are biologically very different. We hypothesized that women with ER+ BC cancers have different clinical risk factors and histologic findings on prior benign breast biopsies than those with ER- BC. Methods: After IRB approval, we examined associations of age at benign biopsy and histologic features of the benign biopsy with ER status of incident BCs within the Mayo Benign Breast Disease Cohort. Benign biopsy slides were reviewed for extent of lobular involution and degree of epithelial proliferation by a single breast pathologist blinded to BC events. Invasive BCs occurring within 15 years after benign biopsy were classified as ER+ if ER staining was >1%. BC case-only associations with ER status were evaluated using multivariate logistic regression. Full-cohort hazard ratios (HR) and 95% confidence intervals (CI) for risk of ER-specific subtypes were estimated using Cox proportion hazards regression. Results: Among 13,410 women undergoing a benign breast biopsy from 1967-2001, 656 invasive BCs (459 ER+, 106 ER, 106 unknown) occurred within 15 years. Women who developed ER+ and ER- BCs were similar in age at the time of their prior benign breast biopsy (p=0.34). Although benign biopsies in women who later developed ER+ BC were more likely to show complete involution (23% vs 15% for ER- BC), this was not statistically significant (p=0.06). However, the degree of epithelial proliferation was significantly associated with ER status of later BCs (p=0.001), with ER+ BCs more likely than ER- BCs to have had a prior biopsy with atypical hyperplasia (16% vs 8%), and ER+ BCs less likely than ER- BCs to have had a prior biopsy with proliferative disease without atypia (33% vs 52%); this association remained after multivariate adjustment (p=0.003). We further pursued the association of epithelial proliferation with differential risk of ER+ and ER- BC in our overall cohort of 13,410 women (Table 1). Compared to women with non-proliferative disease, women with proliferative disease +/- atypia had ∼2-fold hazard ratios for ER- BC, whereas hazard ratios for ER+ BC were higher in women with atypical hyperplasia (∼4-fold) compared to proliferative disease. Hazard Ratio of ER+ and ER- BC within 15 years of BBD based upon degree of epithelial proliferation at benign biopsyCancer TypeGroupNN EventsHazard Ratio (95% CI)p-valueInvasive ER- ≤15 yearsNP8478421.00 (ref)<0.0001 PD4229542.63 (1.76, 3.93) AH70382.60 (1.22, 5.54) Invasive ER+ ≤15 yearsNP84782321.00 (ref)<0.0001 PD42291511.33 (1.09, 1.64) AH703744.41 (3.39, 5.73) NP=nonproliferative disease, PD=proliferative disease without atypia; AH=atypical hyperplasia Conclusion: ER+ and ER- breast cancers appear to have different features on prior benign breast biopsy, with atypical hyperplasia showing increased risk for both types of breast cancer, but a greater risk for ER+ tumors. Citation Format: Amy C Degnim, Derek C Radisky, Robert A Vierkant, Ryan D Frank, Marlene H Frost, Vernon S Pankratz, Celine M Vachon, Tanya L Hoskin, Julie M Cunningham, Chen Wang, Jean-Pierre Kocher, Teresa M Allers, Joanne L Johnson, Tina J Hieken, Karthik Ghosh, Lynn C Hartmann, Daniel W Visscher. Histologic features of benign breast biopsy tissue and association with ER positive and ER negative breast cancer in the Mayo BBD cohort study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-06.

Abstract Background: Statins are the most widely prescribed cholesterol-lowering drugs in the United States, with approximately 25% of US adults using statins by 2008. The anti-carcinogenic effect of statins may reduce the metastatic potential of cancer cells leading to ‘stage migration’ with statin users more likely diagnosed with early rather than late stage cancer. We evaluated the effects of statins on breast cancer stage migration and breast cancer-specific mortality in the Women’s Health Initiative (WHI) Clinical Trial and Observational Study. Methods: The study population included 128,675 postmenopausal women aged 50 to 79 years, with 7,883 newly-diagnosed pathologically-confirmed cases of in situ (19%), local stage (61%), regional stage (19%) and distant stage (1%) breast cancer and 401 deaths due to breast cancer after an average of 11.5 (SD=3.7) years of follow-up. To reduce the possibility of detection bias, we excluded women who did not report a mammogram within 5 years of study entry, and who had no health insurance or medical care provider (n=28,237). Stage was coded using criteria implemented in the Surveillance, Epidemiology and End Results Program and stratified into early stage (in situ and local) vs. late stage (regional and distant). Information on statin use prior to breast cancer diagnosis was collected at baseline and years one, three, six, and nine years post-baseline. Self- and interviewer-administered questionnaires were used to collect risk factor information. Cause of death was based on medical record review by physician adjudicators. Cox proportional hazards regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) to evaluate the relationship between statin use as a time-dependent exposure and diagnosis of late stage breast cancer and breast cancer-specific mortality adjusting for important confounders. For these models, participants who had early stage breast cancer or who died during follow-up were censored at time of diagnosis or death, respectively. We also evaluated the effect of statins stratified by estrogen receptor (ER) status. Statistical tests were two-sided. Results: Statins were used by 10,474 women (8%) at baseline. In the multivariable-adjusted time-dependent model, statin use was associated with a marginal reduction in risk of late stage breast cancer (HR 0.84, 95% CI: 0.70-1.02, p=0.082) and a reduction in risk of late stage estrogen receptor positive breast cancer (HR 0.79, 95% CI: 0.63-0.99, p=0.044). Statin use was also associated with a marginal reduction in breast cancer-specific mortality although it did not reach statistical significance (HR 0.59, 95% CI: 0.32-1.06, p=0.075). Conclusions: In the WHI, statin use was associated with a modest reduction in risk of late stage estrogen positive breast cancer and a non-significant decrease in breast cancer mortality. We are currently performing sensitivity analyses on these models. Studies using other large data sets with longer follow-up and information on cancer-directed therapy are needed to further evaluate this possible association. Citation Format: Monica P Arun, Pinkal Desai, Amy Lehman, Marilyn L Kwan, JoAnn E Manson, Sayeh Lavasani, Sylvia Wasswertheil-Smoller, Gloria E Sarto, Meryl S LeBoff, Jane Cauley, Michele L Cote, Jennifer Beebe-Dimmer, Allison Jay, Rowan T Chlebowski, Michael S Simon. Statins and breast cancer stage and mortality in the Women's Health Initiative cohort [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-04.