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Norton, Larry

https://orcid.org/0000-0003-3701-9250

Mayo Clinic

Memorial Sloan Kettering Cancer Center

Citations 21

Abstract 3282: Determination of cancer susceptibility in probands with breast and ovarian cancer
Schrader, Kasmintan A. , Wubbenhorst, Bradley , Guidugli, Lucia, Corines, Marina, Zhang, Liying , Gupta, Namrata , Hudis, Clifford A. , Lipkin, Steven M. , Nathanson, Katherine L. , Offit, Kenneth , Maxwell, Kara N. , Vijai, Joseph , Hart, Steven N. , Thomas, Tinu , Klein, Robert J. , Neuhausen, Susan L. , Weitzel, Jeffrey N. , Norton, Larry , Getz, Gad , Daly, Mark J. , Altshuler, David , Couch, Fergus J. , Schrader, Intan , Nathanson, Katherine L

Cancer Research | May 1, 2015 | Volume: 74 | Issue: 19_Supplement | Pages: 3282-3282

10.1158/1538-7445.am2014-3282 Get It

Abstract Germline mutations of BRCA1 and BRCA2 underlie joint susceptibility to breast and ovarian cancers, but do not account for all cases. Genome wide association studies show little overlap between common variants associated with breast and ovarian cancer susceptibility, whereas rare variants in genes initially identified as breast cancer susceptibility genes also confer susceptibility to ovarian cancer cases, unselected for breast cancer. Ovarian and breast tumors also are observed in Peutz-Jeghers and possibly in Lynch syndrome. To further elucidate rare germline susceptibilities for breast and ovarian cancer, we have ascertained a unique cohort of 90 BRCA1/2-negative probands with a personal history of breast cancer and ovarian/fallopian tube/peritoneal cancer, unselected for family history. Cases are from the clinical genetics services of Memorial Sloan-Kettering Cancer Center and University of Pennsylvania. Analysis is ongoing using both targeted and exome sequencing approaches. Germline DNA of 69 cases will be subjected to whole exome sequencing. A total of 21 additional cases will undergo targeted sequencing for 28 genes (8 cases) and an extended panel of 54 genes (13 cases). The majority of ovarian cancers are high-grade serous epithelial ovarian carcinoma (n=51), in combination with invasive ductal or DCIS (n=36), invasive lobular (n=4), or unspecified (n=11) breast cancers. The remaining ovarian subgroups comprise other epithelial subtypes; endometrioid (n=9), clear cell (n=3), mucinous and low-grade serous (n=3) and non-epithelial (n=4) or unclassified (n=20), in combination with invasive ductal or DCIS (n=21), invasive lobular (n=5) or unspecified (n=13) breast cancers. Preliminary analysis of the targeted set of genes in 69 cases, reveals 43 predicted pathogenic coding or splice site variants; 17 of which are within PALB2, MSH2, MSH6, BARD1, FANCE, CDKN2A, TP53, SETD2, SIRT1, BRIP1, RAD50, and RAD51D and are not seen in dbSNP138, 1000 Genomes or Exome Variant Server ESP6500 and 26 variants with reported frequencies in MUTYH, MSH6, MLH1, FAM175A, RAD50, UIMC1, JARID2, PHF3, SIRT1, MRE11A, ATM, BRCA2, TP53BP1, CDH1, RAD51D, BRCA1, BABAM1 of less than 1% allele frequency in public databases. Analysis of these variants across and within histologic subtypes is being undertaken to look for specific genotype-phenotype correlations. Analysis of novel candidate genes and pathways by co-segregation, functional analysis, as well as external replication is underway to determine whether shared rare variants, mutated genes, or altered pathways confer cancer susceptibility in this cohort. Germline susceptibility to breast and ovarian cancer is heterogenous and remains a critical research and clinical question. Improved understanding of the susceptibility genetics will allow further examination of the utility of targeted cancer prevention strategies in those who are found to be at risk. Citation Format: Kasmintan A. Schrader, Kara N. Maxwell, Joseph Vijai, Steven Hart, Tinu Thomas, Bradley Wubbenhorst, Lucia Guidugli, Robert Klein, Marina Corines, Liying Zhang, Susan Neuhausen, Jeffrey Weitzel, Namrata Gupta, Larry Norton, Clifford Hudis, Gad Getz, Mark Daly, Steven Lipkin, David Altshuler, Fergus Couch, Katherine Nathanson, Kenneth Offit. Determination of cancer susceptibility in probands with breast and ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3282. doi:10.1158/1538-7445.AM2014-3282
Abstract P2-10-01: PAM50 gene signature is prognostic for breast cancer patients treated with adjuvant anthracycline and taxane based chemotherapy
Liu, MC, Pitcher, BN, Mardis, ER, Davies, SR, Snider, J., Vickery, Tammi L. , Reed, JP, DeSchryver, Katherine, Friedman, PN, Gradishar, WJ, Perez, EA, Martino, Silvana, Citron, M., Winer, EP, Hudis, CA, Perou, CM, Ellis, MJ, Barry, WT, Singh, Baljit , Perez, EA, Norton, Larry

Cancer Research | August 14, 2014 | Volume: 72 | Issue: 24_Supplement | Pages: P2-10-01-P2-10-01

10.1158/0008-5472.sabcs12-p2-10-01 Get It

Abstract Background: Intrinsic breast cancer subtypes determined by the PAM50 assay are reported to be prognostic independent of standard clinicopathological variables. The CALGB (Alliance) 9741 adjuvant trial randomized treatment in a 2×2 factorial design to (i) 2-wk (dose dense; DD) vs 3-wk therapy and (ii) sequential vs concurrent doxorubicin, cyclophosphamide, paclitaxel (A>T>C vs AC>T). DD therapy improved disease-free survival and overall survival (OS) (Citron et al. JCO 2003.). A significant interaction between intrinsic breast cancer subtypes and the use of DD therapy was hypothesized. Methods: C9741 was conducted in collaboration with ECOG, NCCTG, and SWOG. Biospecimens were collected from 1652 of 2005 subjects. Multiplexed gene expression profiling (NanoString Technologies, Inc) generated PAM50 subtype calls (luminal A, luminal B, HER2-enriched, basal-like), risk of relapse (ROR) score, and proliferation score for 1321 cases (80%). Excluded samples were due to insufficient tumor (n = 181) or RNA (n = 150). The primary endpoint was relapse-free survival (RFS). The primary analysis to determine if the clinical benefit of DD therapy is dependent on intrinsic subtype was conducted as a test of interaction in a Cox proportional hazards model (3 degrees of freedom, df; alpha=0.05). Similar analyses were performed for ROR score and proliferation score as continuous measures of risk (1 df). PAM50 subtype, ROR score, and proliferation score were evaluated in separate multivariate models adjusting for number of positive nodes, menopausal status, dose density, and sequence of therapy. Results: Improved outcomes for DD therapy in the evaluable subset mirrored results from the complete dataset (HR = 1.20; 95%CI 0.99–1.44) with a median follow-up of 12.3 yrs. Subtype analysis identified 32% luminal A (n = 417), 26% luminal B (n = 341), 20% HER2-enriched (n = 267), and 22% basal-like (n = 296). Intrinsic subtypes were prognostic of RFS (p < 0.0001) irrespective of treatment assignment with HRs relative to the luminal A subgroup of 1.50 (luminal B), 1.70 (HER2-enriched) and 1.66 (basal-like). No subtype specific treatment effect on RFS was identified (p = 0.44). ROR scores (range 0–100, median 60) were also prognostic of RFS (HR = 1.12 for a 10-unit change; 95% CI 1.07–1.18; p < 0.0001), but no association with DD therapy benefit was seen (p = 0.58). Similar results were obtained for the proliferation score, for OS as a secondary endpoint, and from multivariate models with clinical covariates. Conclusion: The prognostic value of PAM50 subtype, ROR score, and proliferation score remains highly significant in patients treated with contemporary adjuvant anthracycline and taxane based chemotherapy. Intrinsic subtype did not predict for improved survival with the 2-wk DD vs 3-wk treatment schedule; we hypothesize that this is because the prognostic differences by subtype outweighed the modest but significant clinical benefit of DD chemotherapy administration for the overall population. Planned clinical validation studies will assess the ability of PAM50 and other gene signatures to stratify patients and individualize systemic therapy regimens based on the expected risk of distant recurrence. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-01.
Abstract P2-18-09: TBCRC 013: A prospective analysis of the role of surgery in stage IV breast cancer
King, TA, Lyman, JP, Gönen, Mithat , Voci, Amy, Boafo, Camilla, Hwang, ES, Rugo, HS, Alvarado, Michael , Liu, M, Boughey, JC , Jacobs, LK, McGuire, KP, Storniolo, AM, Nanda, Ronica H. , Golshan, Mehra, Isaacs, C, Meszoely, IM, Poznak, CH Van, Babiera, Gildy V., Morrow, Monica, Winer, EP, Hudis, CA, Krontiras, Helen , Bijelić, Lana , Norton, Larry , Wolff, Antonio C.

Cancer Research | August 14, 2014 | Volume: 73 | Issue: 24_Supplement | Pages: P2-18-09-P2-18-09

10.1158/0008-5472.sabcs13-p2-18-09 Get It

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<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<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.
Comparison of Doxorubicin and Cyclophosphamide Versus Single-Agent Paclitaxel As Adjuvant Therapy for Breast Cancer in Women With 0 to 3 Positive Axillary Nodes: CALGB 40101 (Alliance)
Berry, Donald A. , Cirrincione, Constance, Becker, Heather P., Perez, Edith A. , Martino, Silvana, Kimmick, Gretchen , Burstein, Harold J. , Norton, Larry , Muss, Hyman B. , Hudis, Clifford A. , Shulman, Lawrence N. , Cirrincione, Constance T, O'Regan, Ruth, Shapiro, Charles L. , Schneider, Charles J, Muss, Hyman, O'Regan, Ruth M , Schneider, Charles John , Winer, Eric P. , Norton, Larry

Journal of Clinical Oncology | June 17, 2014 | Volume: 32 | Issue: 22 | Pages: 2311-2317

10.1200/jco.2013.53.7142 Get It

PurposeOptimal adjuvant chemotherapy for early-stage breast cancer balances efficacy and toxicity. We sought to determine whether single-agent paclitaxel (T) was inferior to doxorubicin and cyclophosphamide (AC), when each was administered for four or six cycles of therapy, and whether it offered less toxicity.Patients and MethodsPatients with operable breast cancer with 0 to 3 positive nodes were enrolled onto the study to address the noninferiority of single-agent T to AC, defined as the one-sided 95% upper-bound CI (UCB) of hazard ratio (HR) of T versus AC less than 1.30 for the primary end point of relapse-free survival (RFS). As a 2 × 2 factorial design, duration of therapy was also addressed and was previously reported.ResultsWith 3,871 patients enrolled onto the trial, a median follow-up period of 6.1 years, and 437 RFS events, we achieved an HR of 1.26 (one sided 95% UCB, 1.48; favoring AC does not allow a conclusion of noninferiority of T with AC; UCB > 1.3). With 266 patient deaths, the HR for overall survival (OS) was 1.27 favoring AC (UCB, 1.56). The estimated absolute advantage of AC at 5 years is 3% for RFS (91 v 88%) and 1% for OS (95 v 94%). All nine treatment-related deaths were patients receiving AC and are included in the analyses of both RFS and OS. Hematologic toxicity was more common in patients treated with AC, and neuropathy was more common in patients treated with T.ConclusionThis trial did not show noninferiority of T to AC, a conclusion that is unlikely to change with additional events and follow-up. T was less toxic than AC.
Reply to S. Mahesh
Burstein, Harold J. , Piccart, Martine , Perez, Edith A. , Albain, Kathy S. , Norton, Larry , Hudis, Clifford A. , Hortobágyi, Gabriel N. , Wolmark, Norman , Winer, Eric P. , Norton, Larry

Journal of Clinical Oncology | October 16, 2012 | Volume: 30 | Issue: 35 | Pages: 4446-4446

10.1200/jco.2012.45.9677 Get It

Six Cycles of Doxorubicin and Cyclophosphamide or Paclitaxel Are Not Superior to Four Cycles As Adjuvant Chemotherapy for Breast Cancer in Women With Zero to Three Positive Axillary Nodes: Cancer and Leukemia Group B 40101
Cirrincione, Constance, Berry, Donald A. , Becker, Heather P., Perez, Edith A. , Martino, Silvana, Atkins, James N., Kimmick, Gretchen , Norton, Larry , Muss, Hyman B. , Hudis, Clifford A. , Shulman, Lawrence N. , O'Regan, Ruth M , Mayer, Erica L. , Schneider, Charles John , Winer, Eric P. , Norton, Larry

Journal of Clinical Oncology | July 24, 2012 | Volume: 30 | Issue: 33 | Pages: 4071-4076

10.1200/jco.2011.40.6405 Get It

PurposeThe ideal duration of adjuvant chemotherapy for patients with lower risk primary breast cancer is not known. Cancer and Leukemia Group B trial 40101 was conducted using a phase III factorial design to define whether six cycles of a chemotherapy regimen are superior to four cycles. We also sought to determine whether paclitaxel (T) is as efficacious as doxorubicin/cyclophosphamide (AC), but with reduced toxicity.Patients and MethodsBetween 2002 and 2008, the study enrolled women with operable breast cancer and zero to three positive nodes. Patients were randomly assigned to either four or six cycles of either AC or T. Study stratifiers were estrogen receptor/progesterone receptor (ER/PgR), human epidermal growth factor receptor 2 (HER2), and menopausal status. After 2003, all treatment was administered in dose-dense fashion. The primary efficacy end point was relapse-free survival (RFS).ResultsA total of 3,171 patients were enrolled; 94% were node-negative and 6% had one to three positive nodes. At a median follow-up of 5.3 years, the 4-year RFS was 90.9% and 91.8% for six and four cycles, respectively. The adjusted hazard ratio (HR) of six to four cycles regarding RFS was 1.03 (95% CI, 0.84 to 1.28; P = .77). The 4-year OS was 95.3% and 96.3% for six and four cycles, respectively, with an HR of six to four cycles of 1.12 (95% CI, 0.84 to 1.49; P = .44). There was no interaction between treatment duration and chemotherapy regimen, ER/PgR, or HER2 status on RFS or OS.ConclusionFor women with resected primary breast cancer and zero to three positive nodes, we found no evidence that extending chemotherapy regimens of AC or single-agent T from four to six cycles improves clinical outcome.
Choosing the Best Trastuzumab-Based Adjuvant Chemotherapy Regimen: Should We Abandon Anthracyclines?
Burstein, Harold J. , Piccart, Martine , Perez, Edith A. , Albain, Kathy S. , Norton, Larry , Hudis, Clifford A. , Hortobágyi, Gabriel N. , Wolmark, Norman , Winer, Eric P. , Norton, Larry

Journal of Clinical Oncology | May 22, 2012 | Volume: 30 | Issue: 18 | Pages: 2179-2182

10.1200/jco.2012.42.0695 Get It

p53 Expression in Node-Positive Breast Cancer Patients: Results from the Cancer and Leukemia Group B 9344 Trial (159905)
Lara, Jonathan F. , Thor, Ann D. , Dressler, Lynn G., Broadwater, Gloria , Bleiweiss, Ira J. , Edgerton, Susan M., Cowan, David P., Goldstein, Lori J. , Martino, Silvana, Henderson, I. Craig, Norton, Larry , Hudis, Clifford A. , Berry, Donald A. , Hayes, Daniel F. , B, for the Cancer and Leukemia Group, Ingle, James N. , Winer, Eric P. , Ellis, Matthew J. , B, for the Cancer and Leukemia Group, Norton, Larry

Clinical Cancer Research | June 21, 2011 | Volume: 17 | Issue: 15 | Pages: 5170-5178

10.1158/1078-0432.ccr-11-0484 Get It

Abstract Purpose: p53 as a prognostic and predictive factor in early-stage breast cancer has had mixed results. We studied p53 protein expression, by immunohistochemistry, in a randomized clinical trial of stage II patients treated with adjuvant doxorubicin and cyclophosphamide with or without paclitaxel [Cancer and Leukemia Group B (CALGB) 9344, INT0148]. Patients and Methods: Epithelial p53 expression was evaluated using two immunohistochemical antibodies (DO7 and 1801) in formalin-fixed, paraffin-embedded tissue from patients with node-positive breast cancer who were randomized to four cycles of cyclophosphamide and one of three doses of doxorubicin (60, 75, or 90 mg/m2; AC) and to receive four subsequent cycles of paclitaxel (T) or not. Prognostic and predictive value of p53 protein expression was assessed, independent of treatment assignment, for escalating doses of doxorubicin or addition of T with endpoints of relapse-free (RFS) and overall survival (OS). Results: Of 3,121 patients, 1,887 patient specimens treated on C9344 were obtained, passed quality control, and evaluated for p53 expression. Expression was 23% and 27% for mAbs 1801 and D07, respectively, with 92% concordance. In univariate analysis, p53 positivity was associated with worse OS with either antibody, but only p53 staining with monoclonal antibody 1801 had significantly worse RFS. In multivariate analysis, p53 was not predictive of RFS or OS from either doxorubicin dose escalation or addition of paclitaxel regardless of the antibody. Conclusion: Nuclear staining of p53 by immunohistochemistry is associated with worse prognosis in node-positive patients treated with adjuvant doxorubicin-based chemotherapy but is not a useful predictor of benefit from doxorubicin dose escalation or the addition of paclitaxel. Clin Cancer Res; 17(15); 5170–8. ©2011 AACR.
Late Extended Adjuvant Treatment With Letrozole Improves Outcome in Women With Early-Stage Breast Cancer Who Complete 5 Years of Tamoxifen
Goss, Paul E., Pater, Joseph L. , Martino, Silvana, Robert, Nicholas J. , Muss, Hyman B. , Piccart, Martine , Castiglione, Monica, Shepherd, Lois E. , Livingston, Robert B., Davidson, Nancy E. , Norton, Larry , Perez, Edith A. , Abrams, Jeffrey S. , Cameron, David , Palmer, Michael , Ingle, James N. , Pritchard, Kathleen I. , Tu, Dongsheng , Cameron, David , Norton, Larry

Journal of Clinical Oncology | March 11, 2008 | Volume: 26 | Issue: 12 | Pages: 1948-1955

10.1200/jco.2007.11.6798 Get It

Purpose The National Cancer Institute of Canada Clinical Trials Group MA.17 trial examined the efficacy of letrozole (LET) started within 3 months of 5 years of adjuvant tamoxifen in postmenopausal hormone receptor–positive early-stage breast cancer. When the trial was unblinded, patients who received placebo (PLAC) were offered LET. Patients and Methods This cohort analysis describes the outcomes of women assigned PLAC at the initial random assignment after unblinding. Efficacy outcomes of women who chose LET (PLAC-LET group) were compared with those who did not (PLAC-PLAC group) by the hazard ratios and by P values calculated from Cox models that adjusted for imbalances between the groups. Toxicity analyses included only events that occurred after unblinding. Results There were 1,579 women in the PLAC-LET group (median time from tamoxifen, 2.8 years) and 804 in the PLAC-PLAC group. Patients in the PLAC-LET group were younger; had a better performance status; and were more likely to have had node-positive disease, axillary dissection, and adjuvant chemotherapy than those in the PLAC-PLAC group. At a median follow-up of 5.3 years, disease-free survival (DFS; adjusted hazard ratio [HR], 0.37; 95% CI, 0.23 to 0.61; P < .0001) and distant DFS (HR, 0.39; 95% CI, 0.20 to 0.74; P = .004) were superior in the PLAC-LET group. More self-reported new diagnoses of osteoporosis and significantly more clinical fractures occurred in the women who took LET (5.2% v 3.1%, P = .02). Conclusion Interpretation of this cohort analysis suggests that LET improves DFS and distant DFS even when there has been a substantial period of time since the discontinuation of prior adjuvant tamoxifen.
Efficacy of Letrozole Extended Adjuvant Therapy According to Estrogen Receptor and Progesterone Receptor Status of the Primary Tumor: National Cancer Institute of Canada Clinical Trials Group MA.17
Goss, Paul E., Martino, Silvana, Robert, Nicholas J. , Muss, Hyman B. , Piccart, Martine , Castiglione, Monica, Shepherd, Lois E. , Livingston, Robert B., Davidson, Nancy E. , Norton, Larry , Perez, Edith A. , Abrams, Jeffrey S. , Cameron, David , Palmer, Michael , Pater, Joseph L. , Ingle, James N. , Tu, Dongsheng , Pritchard, Kathleen I. , Cameron, David , Norton, Larry

Journal of Clinical Oncology | April 24, 2007 | Volume: 25 | Issue: 15 | Pages: 2006-2011

10.1200/jco.2006.09.4482 Get It

Purpose Controversy exists regarding estrogen (ER) and progesterone (PgR) receptor expression on efficacy of adjuvant endocrine therapy. In the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial, the benefit of anastrozole over tamoxifen was substantially greater in ER+/PgR–than ER+/PgR+ tumors. In BIG 1-98 (Breast International Group), the benefits of letrozole over tamoxifen were the same in ER+ tumors irrespective of PgR. MA.17 randomized postmenopausal women after 5 years of tamoxifen, to letrozole or placebo. We present outcomes according to tumor receptor status. Patients and Methods Disease-free survival (DFS) and other outcomes were assessed in subgroups by ER and PgR status using Cox's proportional hazards model, adjusting for nodal status and prior adjuvant chemotherapy. Results The DFS hazard ratio (HR) for letrozole versus placebo in ER+/PgR+ tumors (N = 3,809) was 0.49 (95% CI, 0.36 to 0.67) versus 1.21 (95% CI, 0.63 to 2.34) in ER+/PgR–tumors (n = 636). ER+/PgR+ letrozole patients experienced significant benefit in distant DFS (DDFS; HR = 0.53; 95% CI, 0.35 to 0.80) and overall survival (OS; HR = 0.58; 95% CI, 0.37 to 0.90). A statistically significant difference in treatment effect between ER+/PgR+ and ER+/PgR–subgroups for DFS was observed (P = .02), but not for DDFS (P = .06) or OS (P = .09). Conclusion These results suggest greater benefit for letrozole in DFS, DDFS, and OS in patients with ER+/PgR+ tumors, implying greater activity of letrozole in tumors with a functional ER. However, because this is a subset analysis and receptors were not measured centrally, we caution against using these results for clinical decision making.