Supplementary Figure 1 a. Doxorubicin resistance of DOXO-R C8 cells was further validated using the cell viability assay (SRB) following 48 hrs treatment with DOXO, n=4 independent experiment, 3 replicates/experiment. **p<0.01 vs parental. b DOXO-R cells are not cross resistant to cisplatin. Cell viability measured by alamar blue following treatment with cisplatin for 48hrs, n=4 independent experiment, 3 replicates/experiment. c ABCB1 mRNA levels are not increased in DOXO-R cells compared to parental cells. Gene expression data showing LOG2FC values of C1, C8, CD and CF colonies compared to parental cells for ABCB1 gene. LOG2FC do not reach significance, i.e. LOG2FC >0.6 and pval<0.05. d DOXO-R cells do not express more ALDH+ve cells than parental cells. % of ALDH+ve cells quantified by flow cytometry, n=3 independent experiments, *p<0.05 vs parental. e Doubling time (hrs) of parental (P) and DOXO-R C1 and C8 cells measured by alamar blue, n=4 independent experiment, 3 replicates/experiment. *p<0.05 vs parental, n.s. = not significant. f Light microscopy of parental PTX selected colonies (PTX-CD and PTX-CF) showing that PTX colonies are different from parental cells but similar to DOXO-R C1 and C8 with neuron-like projections described in Fig. 2a. g Electron micrographs of PTX-CD and CF cells showing increased LDs (left panel, arrows), neuron-like projections (middle panel, arrow heads) and cytoplasmic regions filled with numerous small mitochondria (right panel, white circles), similar to DOXO-R C1 and C8 cells described in Fig. 2a. h Phalloidin staining showing PTX-CF cells but not parental cells exhibit PGCCs with neuron-like projections as shown in DOXO-R C1 and C8 cells in Fig. 2b. Scale bars 10, 5 and 2 µm. For a-d, data represent means +/- SEM. Student t-test was done for c-e. For a and b, two-way anova analysis with multiple comparison test (Dunnet) was performed. Supplementary Figure 2. Example of DOXO-R PGCC with neuron-like projection at high cell confluence visible by light microscopy at lower magnification (4x). Supplementary Figure 3. Omics analysis of chemoresistant TNBC cells and tumors. Supplementary Figure 4. a,b PPARG and PLIN4 mRNA quantification by RT-PCR following transient silencing of PPARG using 2 siRNAs (2 and 5) and siRNA ctrl in DOXO-R cells (n=3 independent experiment, *p<0.05, **p<0.01). Supplementary Figure 5. KM plots. Supplementary Figure 6. a,b Cell viability of MDA-MB-436 and CRC T786 (5000 cells/well) measured by alamar blue following treatment with DOXO in F-medium for 72hrs (n{greater than or equal to}3). Supplementary Table S0. Summary of the molecular characteristics identifying the DOXO-R phenotype in chemoresistant TNBC cells and tumors.

PURPOSE:To determine, in women with primary operable breast cancer, if preoperative doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan; AC) therapy yields a better outcome than postoperative AC therapy, if a relationship exists between outcome and tumor response to preoperative chemotherapy, and if such therapy results in the performance of more lumpectomies. PATIENTS AND METHODS:Women (1,523) enrolled onto National Surgical Adjuvant Breast and Bowel Project (NSABP) B-18 were randomly assigned to preoperative or postoperative AC therapy. Clinical tumor response to preoperative therapy was graded as complete (cCR), partial (cPR), or no response (cNR). Tumors with a cCR were further categorized as either pathologic complete response (pCR) or invasive cells (pINV). Disease-free survival (DFS), distant disease-free survival (DDFS), and survival were estimated through 5 years and compared between treatment groups. In the preoperative arm, proportional-hazards models were used to investigate the relationship between outcome and tumor response. RESULTS:There was no significant difference in DFS, DDFS, or survival (P = .99, .70, and .83, respectively) among patients in either group. More patients treated preoperatively than postoperatively underwent lumpectomy and radiation therapy (67.8% v 59.8%, respectively). Rates of ipsilateral breast tumor recurrence (IBTR) after lumpectomy were similar in both groups (7.9% and 5.8%, respectively; P = .23). Outcome was better in women whose tumors showed a pCR than in those with a pINV, cPR, or cNR (relapse-free survival [RFS] rates, 85.7%, 76.9%, 68.1%, and 63.9%, respectively; P < .0001), even when baseline prognostic variables were controlled. When prognostic models were compared for each treatment group, the preoperative model, which included breast tumor response as a variable, discriminated outcome among patients to about the same degree as the postoperative model. CONCLUSION:Preoperative chemotherapy is as effective as postoperative chemotherapy, permits more lumpectomies, is appropriate for the treatment of certain patients with stages I and II disease, and can be used to study breast cancer biology. Tumor response to preoperative chemotherapy correlates with outcome and could be a surrogate for evaluating the effect of chemotherapy on micrometastases; however, knowledge of such a response provided little prognostic information beyond that which resulted from postoperative therapy.

Table S1: List of regions of genes with increased CNV (>= 0.5) and gene expression (>= 0.5) in DOXO-R cells compared to parental cells Table S2: List of all fold change and pvalue of DOXO-R C1 and C8 (vs parental cells) from gene expression analysis. Table S3. GSEA using the C5 module for the 1852 genes with gene expression fold change > 1.5 (pval < 0.05) in DOXO-R C1 and C8 Table S4. GSEA using the C5 module for the 407 genes with gene expression fold change > 1.5 (pval < 0.05) and CNV change > 0.5 Table S5: Mean LOG2FC of genes commonly up-regulated in C1 and C8 Table S6: Proteins that are significantly upregulated according to the following criteria. (i) only present in one or two of the Dox resistant cell lines (**) with at least 3 and 2 unique peptides, respectively. (ii) At least 1.5-fold upregulated in both cell lines with a maximum relative standard deviation (RSD) of 31% across control replicates and 25% RSD across resistant cell line replicates. Table S7: GSEA using the C5 module for the 98 overexpressed proteins in DOXO-R vs parental cells Table S8: mRNA fold change (POST vs PRE NAC) for 9 chemoresistant TNBC patients. Table S9: GSEA using the C5 module for NEO2 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S10: GSEA using the C5 module for NEO24 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S11: GSEA using the C5 module for NEO25 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S12: GSEA using the C5 module for NEO27 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S13: GSEA using the C5 module for NEO28 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S14: GSEA using the C5 module for NEO30 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S15: GSEA using the C5 module for NEO31 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S16: GSEA using the C5 module for NEO35 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis. Table S17: GSEA using the C5 module for NEO44 up regulated genes > 2.5 FC. The complete list of genes are listed below the GSEA analysis.

Background: Although the role of the 21-gene Breast Recurrence Score® assay is well established to predict response to adjuvant chemotherapy in the setting of node-negative hormone receptor (HR)-positive, HER2-negative breast cancers (BC), fewer studies have evaluated the assay in the neoadjuvant setting. Due to the correlation between a high Recurrence Score® (RS) result and pathological complete response (pCR), the Breast Recurrence Score assay has been used to aid in selecting between chemotherapy (CT) or endocrine therapy. We wanted to further understand the impact of the assay upon physician treatment recommendations and the use of chemotherapy in this patient cohort. Methods: We conducted a multicenter, prospective, observational study in patients with clinically node-negative HR-positive, HER2-negative BC with T2-T3 disease being considered for neoadjuvant therapy. Physicians were required to complete two questionnaires indicating treatment choice, including CT, endocrine therapy, or surgery, prior to and post availability of RS result. Patients were followed up for 6 months after commencement of neoadjuvant therapy. The primary objective was to evaluate the change in the physician’s recommendation for neoadjuvant CT prior to and post assay results. As a secondary objective, we also evaluated the impact of the RS result on physician’s expressed level of confidence. Results: A total of 70 patients were enrolled between April 2018 and November 2021 at five hospital centers, as part of the McPeak Sirois Group of Quebec. The median age of the cohort was 60 years (range, 30 to 79 years). 24.3 % (n=17) of the cohort consisted of patients aged < 50 years, and 75.7% (n=53) were ≥ to 50 years. 29.0% (n=20) of the patients had a RS < 16, 39.1% (n=27) had a RS between 16-25, and 31.9% (n=22) had a RS > 25. For the entire cohort, the RS result led to a net reduction in chemotherapy recommendation by 33.3% (OR (odds of having CT post-RS recommendation versus pre-RS recommendation) = 0.23 [95% CI: 0.12-0.44]; P< 0.0001), and 39.2% net reduction in the use of chemotherapy at 6-month follow-up (OR = 0.18 [95% CI: 0.09-0.35]; P< 0.0001). Furthermore, the RS result led to a 35.3% net reduction in physician recommendation of CT for patients < 50 years (OR = 0.19 [95% CI: 0.04-0.83]; P=0.027) and a 32.7% net reduction for patients ≥ 50 years (OR = 0.24 [95% CI: 0.11-0.50]; P=0.0001). For patients with a RS < 16, there was a reduction in CT recommendation by 75.0%, and by 44.4% for patients with a RS between 16 - 25 (OR = 0.15 [95% CI: 0.06-0.38]; P< 0.0001). Moreover, RS results led to an increase in confidence in physician treatment decisions for 59.4% of patients (OR = 12.53 [95% CI: 5.46-28.78]; P< 0.0001). Conclusion: We determined that the 21-gene Breast Recurrence Score assay altered neoadjuvant treatment decisions, leading to a reduction in the use of chemotherapy by about one-third, regardless of age. Additionally, the assay increased physician confidence in their treatment recommendation for about 60% of patients. This demonstrates the potential clinical utility of the assay to decrease the use of CT in the neoadjuvant setting amongst HR-positive, node-negative BC patients in Quebec. Citation Format: Mariya Yordanova, Lucas Sideris, Pierre Dubé, Jean-Francois Boileau, Julie Lemieux, Catalin Mihalcioiu, Sylvie Levesque, Marie-Claude Guertin, Erica Patocskai, Rami Younan, André Robidoux, Saima Hassan. The impact of the 21-gene Recurrence Score® assay upon physician treatment recommendations in the neoadjuvant setting in lymph node-negative breast cancer patients in a multicenter prospective study in Quebec [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-39.

Tables S1-S6 and Figures S1-S5

Perspectives on this Article from Update of the National Surgical Adjuvant Breast and Bowel Project Study of Tamoxifen and Raloxifene (STAR) P-2 Trial: Preventing Breast Cancer

Abstract Background The 21-gene Breast Recurrence Score (RS) assay, “the assay”, has led to a paradigm shift for patients with hormone receptor-positive, node-negative early breast cancer and is emerging as an important tool to assist physician-patient decisions in foregoing chemotherapy in node-positive patients. We wanted to better understand the impact of the RS assay in node-positive patients upon physician treatment decisions and treatment cost in Quebec, Canada. Patients and Methods We conducted a multicenter, prospective observational trial for Estrogen/Progesterone Receptor (ER/PR)- positive, Human Epidermal Growth Factor Receptor 2 (HER2)-negative breast cancer patients with 1-3 positive lymph nodes. Physicians completed a questionnaire indicating treatment choice prior to and post availability of RS results. The primary endpoint was change in the physician’s recommendation for chemotherapy prior to and post assay results. Secondary endpoints included change in physician’s expressed level of confidence, and changes in estimated cost of recommended treatments prior to and post assay results. Results For the entire cohort, physician recommendation for chemotherapy was reduced by an absolute 67.1% by knowledge of the RS assay result (P < .0001). Physician recommendation of chemotherapy was decreased by 75.9% for patients RS result <14 (P < .0001); and 67.5% for patients with RS result 14-25 (P < .0001). Changes in treatment recommendations were associated with an overall reduction in cost by 73.7% per patient, and after incorporating the cost of the RS test, a cost benefit of $823 CAN at 6-month follow-up. Conclusion Altogether, we established that the assay led to a two-third reduction in the use of chemotherapy, and was a cost-effective approach for hormone receptor-positive, node-positive breast cancer.

Results from adjuvant trials evaluating 6 cycles of epirubicin-based chemotherapy regimens suggested these programs may be more effective than 4 cycles of doxorubicin-based chemotherapy. NSABP B-36 was a phase III clinical trial originally designed as a 2 × 2 factorial study comparing 6 cycles of 5-FU, epirubicin, and cyclophosphamide (FEC-100) to 4 cycles of conventional doxorubicin and cyclophosphamide (AC) with celecoxib or placebo. Shortly after activation, concerns regarding increased cardiovascular risks among selective COX-2 inhibitors resulted in a decision to remove the celecoxib/placebo from the trial. Women with histologically node-negative invasive breast cancer who had undergone primary surgery with a lumpectomy or total mastectomy were eligible. Primary endpoint was disease-free survival (DFS). Between May 2004 and July 2008, 2722 patients were enrolled. Administration of FEC-100 did not result in improvement in DFS compared to AC (HR 1.09; 95% CI 0.92–1.29, p value = 0.31). The effect of FEC-100 compared to AC on DFS was significantly different for receptor-positive (HR 1.32, 95% CI 1.05–1.66) compared to receptor-negative patients (HR 0.86, 95% CI 0.66–1.11) (treatment-by-receptor status interaction p value = 0.02). There was no statistically significant difference in the effect of treatment on overall survival (OS) with FEC-100 compared to AC (HR 1.06; 95% CI 0.84–1.35, p value = 0.61). Overall, Grade 3 and 4 adverse events were more frequent in the FEC-100 group. The results of B-36 do not support use of six-cycle anthracycline-based regimens in node-negative breast cancer. Prolongation of anthracycline-based therapy with FEC-100 does not improve DFS or OS, relative to AC for 4 cycles, and was associated with expected increases in toxicity. A statistically significant interaction between treatment and hormone receptor status favoring AC in hormone-receptor-positive breast cancers is consistent with the hypothesis that optimal duration of chemotherapy may be four cycles in these patients. Late cardiac events and deaths prior to recurrence or second cancer were infrequent on both arms, but slightly higher with FEC-100. ClinicalTrials.gov: NCT00087178.

Background:The Adjuvant Zoledronic Acid (ZA) study in early breast cancer (AZURE) showed correlation between a nonamplified MAF gene in the primary tumor and benefit from adjuvant ZA. Adverse ZA outcomes occurred in MAF-amplified patients. NSABP B-34 is a validation study. Methods:A retrospective analysis of MAF gene status in NSABP B-34 was performed. Eligible patients were randomly assigned to standard adjuvant systemic treatment plus 3 years oral clodronate (1600 mg/daily) or placebo. Tumors were tested for MAF gene amplification and analyzed for their relationship to clodronate for disease-free survival (DFS) and overall survival (OS) in MAF nonamplified patients. All statistical tests were 2-sided . Results:MAF status was assessed in 2533 available primary tumor samples from 3311 patients. Of these, 37 withdrew consent; in 77 samples, no tumor was found; 536 assays did not meet quality standards, leaving 1883 (77.8%) evaluable for MAF assay by fluorescence in situ hybridization (947 from placebo and 936 from clodronate arms). At 5 years, in MAF nonamplified patients receiving clodronate, DFS improved by 30% (hazard ratio = 0.70, 95% confidence interval = 0.51 to 0.94; P = .02). OS improved at 5 years (hazard ratio = 0.59, 95% confidence interval = 0.37 to 0.93; P = .02) remaining statistically significant for clodronate throughout study follow-up. Conversely, adjuvant clodronate in women with MAF-amplified tumors was not associated with benefit but rather possible harm in some subgroups. Association between MAF status and menopausal status was not seen. Conclusions:Nonamplified MAF showed statistically significant benefits (DFS and OS) with oral clodronate, supporting validation of the AZURE study.

Abstract Background: Locoregional lymph node involvement has historically been used as the most important deciding factor for the administration of chemotherapy in the adjuvant setting of breast cancer patients. The 21-gene Breast Recurrence Score® assay (the assay) is emerging as an important tool to assist with chemotherapy decisions amongst hormone receptor (HR)-positive, node-positive breast cancer (BC) patients. Previous studies have suggested that node-positive patients with low Recurrence Score (RS) results do not benefit from chemotherapy. We wanted to better understand the impact of the assay upon physician treatment decisions and treatment cost in this patient cohort. Methods: We conducted a multicenter prospective observational trial for ER/PR-positive HER2-negative BC patients that have undergone surgical treatment for T1-T3 disease and 1-3 positive lymph nodes. Physicians were required to complete a questionnaire indicating treatment choice prior to and post availability of Recurrence Score results. Patients were enrolled in the study from the time of consent to 6 months after the start of adjuvant therapy. The primary endpoint was change in the physician’s recommendation for chemotherapy prior to and post assay results. Secondary endpoints include the change in recommendation for additional growth factor (GF) supportive therapy, change in physician’s expressed level of confidence, and changes in estimated cost of recommended treatments prior to and post assay results. Results: 70 patients were enrolled between March 2018 and September 2019 at five hospital centers, as part of the McPeak Sirois Group of Quebec. The median age of the cohort was 61 years (range, 38 to 82 years). 18.5% (n=13) of the cohort consisted of patients < 50 years, and 81.4% (n=57) were > or = to 50 years. 64.3% (n=45) of the patients had one positive lymph node and 35.7% (n=25) of the patients had 2 or 3 positive lymph nodes. 25.7% (n=18) of the patients had a RS < 11 and 68.6% (n=48) had a RS result between 11-25. For the entire cohort, we found that the proportion of patients for whom chemo-hormonal therapy was recommended was reduced by an absolute 67.1% by knowledge of the RS result (OR (odds of having chemo-hormonal therapy post-RS recommendation versus pre-RS recommendation) = 0.03 [95% CI: 0.01-0.08]; P<0.0001). The RS results led to an absolute reduction in physician recommendation in chemo-hormonal therapy by 38.5% for patients < 50 years, and by 73.7% of patients (OR=0.02 [95% CI: 0.01-0.06]; P <0.0001) for patients > or = to 50 years. Changes in treatment recommendation were identified for patients with one positive node, 73.3% (OR=0.02 [95% CI: 0.01-0.07]; P<0.0001); and for patients with two or three positive nodes, 56.0% (OR=0.06 [95% CI: 0.02-0.23]; P<0.0001). Recommendations for GF supportive therapy due to RS results decreased by 42.6% (OR=0.16 [95% CI: 0.07-0.34]; P <0.0001). Moreover, RS results led to an increase in confidence in physician treatment decisions for 68.6% of patients (OR=18.3 [95% CI: 7.90-42.28]; P <0.0001). We found that the cost of chemotherapy, in addition to anti-emetics and GF supportive therapy, decreased by 69.9% per patient (pre-RS mean, $3,968 CAN; versus post-RS mean, $1,196 CAN) (P <0.0001). Conclusions: Overall, we found that the 21-gene Breast Recurrence Score® assay changed physician treatment decisions in about two-thirds of all patients with hormone receptor-positive, node-positive BC, regardless of the number of positive nodes (up to 3). The assay increased physician confidence and was associated with an important decrease in treatment cost. Taken together, the assay is a cost-effective approach that can decrease the use of chemotherapy amongst HR-positive, node-positive BC patients in Quebec. Citation Format: Saima Hassan, Rami Younan, Erica Patocskai, Louise Provencher, Brigitte Poirier, Lucas Sideris, Pierre Dubé, Jean-Francois Boileau, Catalin Mihalcioiu, André Robidoux. A prospective multicenter study evaluating the impact of the 21-Gene Breast Recurrence Score® upon physician treatment decision and cost in lymph node-positive breast cancer patients in Quebec [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-27.

Abstract Background: The achievement of pCR (breast and axilla) is strongly prognostic for event-free (EFS) and overall survival (OS) in EBC (Cortazar 2014), and modulation of therapy improves long-term outcomes for patients with HER2-positive disease not achieving pCR (Von Minckwitz 2019). We sought to investigate prognostic factors for EFS and OS among patients with and without pCR following neoadjuvant systemic treatment consisting of chemotherapy plus anti-HER2 therapy. Methods: We used individual data from 3,710 patients randomized in 11 neoadjuvant trials for HER2-positive EBC with N≥100 patients enrolled, available data for pCR, EFS, and OS, and follow-up ≥3 years. We assessed baseline clinical tumor size (cT) and clinical nodal status (cN) as prognostic factors using stratified (by trial and treatment) Cox models separately for hormone-receptor (HR)-positive vs. HR-negative disease, and for patients who achieved pCR (pCR+; ypT0/is, ypN0) vs. patients who did not achieve pCR (pCR-). Results: The median follow-up overall was 61.2 months. The table shows hazard ratios and 5-year Kaplan-Meier estimates of OS (5yr OS) according to HR and pCR. Comparable results were observed for EFS. Both cT (1-2 vs. 3-4) and cN (cN- vs. cN+) were independent prognostic factors for OS in most subsets, including in pCR+ patients. Conclusions: These results confirm that patients achieving pCR have far better long-term outcomes than patients who do not, and that traditional poor prognostic features namely tumour size and nodal status remain important even after a pCR, with no clear evidence that the relative impact of unfavourable (cT3-4 or cN+) features is different in patients who achieve a pCR than in those who did not. Key words: neo-adjuvant therapy, HER2-targeted therapy, pathological complete response, prognostic factors, overall survival Funding: German Breast Group HR pCRBaseline cT/cN DeathsPatients5yr OS (%)Hazard ratio* [95% CI]HR+ pCR+cT1-2/cN-521298.6%1.0 (reference)(N= 637)cT3-4/cN-46592.9%0.49 [0.21-1.14]cT1-2/cN+720095.1%0.82 [0.34-1.99]cT3-4/cN+1016094.0%0.40 [0.13-1.25]HR+ pCR-cT1-2/cN-1737796.3%1.0 (reference)(N=1399)cT3-4/cN-2514381.8%0.51 [0.36-0.73]cT1-2/cN+4844888.9%0.71 [0.49-1.03]cT3-4/cN+6443184.9%0.36 [0.23-0.58]HR- pCR+cT1-2/cN-319698.1%1.0 (reference)(N=860)cT3-4/cN-89090.4%0.56 [0.32-0.98]cT1-2/cN+1928092.4%0.49 [0.24-0.98]cT3-4/cN+3029489.5%0.27 [0.12-0.64]HR- pCR-cT1-2/cN-2114083.2%1.0 (reference)(N=814)cT3-4/cN-207871.4%0.46 [0.34-0.64]cT1-2/cN+4225181.6%0.76 [0.53-1.09]cT3-4/cN+11634561.9%0.35 [0.22-0.56]*Hazard ratio cT1-2/cN- vs. higher risk cohorts Citation Format: Sibylle Loibl, Michael Untch, Marc Buyse, André Robidoux, Luca Gianni, Andreas Schneeweiss, Pierfranco Conte, Martine Piccart, Hervé Bonnefoi, Christian Jackisch, Valentina Nekljudova, Joseph Costantino, Pinuccia Valagussa, Colin Neate, Richard Gelber, Coralie Poncet, Pierre Squifflet, Everardo Saad, Dominik Heinzmann, Carsten Denkert, Charles E Geyer, Javier Cortes, Valentina Guarneri, Evandro de Azambuja, David Cameron, Gustavo Ismael, Gunter von Minckwitz, Norman Wolmark, Patricia Cortazar. Pathologic complete response (pCR) and prognosis following neoadjuvant chemotherapy plus anti-HER2 therapy of HER2-positive early breast cancer (EBC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-06-02.

Obesity has been associated with poor breast cancer (BC) outcomes. We investigated whether a standardized, telephone-based weight loss lifestyle intervention in the adjuvant setting would impact BC outcomes. We conducted a multicenter trial randomizing women 1:1 to mail-based educational material alone (control) or combined with a standardized, telephone-based lifestyle intervention that focused on diet, physical activity, and behavior and involved 19 calls over 2 years to achieve up to 10% weight loss. In all, 338 (of 2150 planned) T1-3, N0-3, M0 hormone receptor positive BC patients with body mass index (BMI) ≥24 kg/m 2 receiving adjuvant letrozole were randomized (enrolment ended due to funding loss). The primary outcome was disease-free survival (DFS); secondary outcome was Overall Survival (OS). At 8 years’ median follow-up, in a planned analysis, DFS and OS were compared using the Kaplan–Meier method. Baseline BMI and other characteristics were similar between study arms. In all, 22 of 171 (12.9%) in the lifestyle intervention arm versus 30 of 167 (18.0%) in the education had DFS events; the hazard ratio (HR) was 0.71 (95% confidence interval [CI]: 0.41–1.24, p = 0.23). Although loss of funding reduced sample size, we view these hypothesis generating results as compatible with our hypothesis of a potential beneficial effect of a lifestyle intervention on DFS. They provide support for completion of ongoing randomized controlled trials of the effect of lifestyle interventions in BC outcomes.

Background: Targeted axillary dissection (TAD) is a novel technique in the field of surgical oncology. Our overarching aim is to assess the safety of this procedure in the Canadian setting and amongst high-risk patients.

Abstract Purpose: In NSABP B-41, pathologic complete response (pCR) was associated with prolonged survival among women with HER2-positive operable breast cancer treated with neoadjuvant chemotherapy and lapatinib, trastuzumab, or the combination. We used a large human breast cancer gene expression panel to select candidate prognostic biomarkers for pCR among women treated with trastuzumab in NSABP B-41. Patients and Methods: Eligible patients had a baseline preadjuvant treatment core biopsy sample, known pCR status, and no withdrawal of consent. We analyzed extracted RNA using the human nCounter Breast Cancer 360 gene expression panel. Gene counts were normalized to housekeeping genes and transformed into logarithmic scale with base 2. To screen for candidate genes and metagene signatures prognostic of pCR, we used univariate logistic regression. Variable selection was done by multivariable logistic regression with lasso regularization. Results: Analyses of data from 130 patients revealed that a composite of gene expression from 19 genes and one gene signature appeared to predict pCR in women with HER2-positive early-stage breast cancer undergoing neoadjuvant chemotherapy with trastuzumab-containing regimens. The identified genes are involved in important pathways such as epithelial–mesenchymal transition, adhesion and migration, estrogen receptor signaling, DNA damage and repair, apoptosis, and proliferation. The AUC from a 10-fold cross-validation on predicting pCR, with these 20 genomic markers in a logistic regression model, was 0.73. Conclusions: The expression level of ERBB2, ESR1, and a few other genomic markers was highly predictive of pCR after trastuzumab-containing regimens. These findings need to be validated and calibrated in future studies.