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Wilke, Lee G.

https://orcid.org/0000-0003-1210-6294

Mayo Clinic

University of Wisconsin–Madison

Citations 8

Abstract SS2-01: Impact of the COVID-19 pandemic on the multidisciplinary management of breast cancer: Initial analysis of the american society of breast surgeons mastery COVID-19 registry
Nguyen, Toan T. , Yang, Qiuyu , Wagner, Kathryn A , Brown, Eric, Dietz, Jill R. , Wilke, Lee G. , Hanlon, Bret M. , Strickland, Pamela, Boughey, Judy C.

Cancer Research | February 15, 2021 | Volume: 81 | Issue: 4_Supplement | Pages: SS2-01-SS2-01

10.1158/1538-7445.sabcs20-ss2-01 Get It

Abstract Background: The COVID-19 pandemic rapidly altered health care worldwide. To save protective equipment and minimize exposures, many hospitals stopped some or all cancer surgery, leading oncologic providers to quickly adjust patient management. The goal of this study is to describe the breast cancer patient level changes which occurred during the initial months of COVID-19 in the United States. Methods: The American Society of Breast Surgeons developed a COVID-19 specific registry, within the established HIPPA compliant Mastery of Breast Surgery Program. Surgeons entered patient demographic data as well as their surgical and medical care (Neoadjuvant endocrine (NET) vs Neoadjuvant chemotherapy (NCT)). Data fields tracked whether decisions were usual for that practice, or modified due to COVID-19. Results: Between 3/1 and 6/17/2020, data from 1781 patients was entered by 154 surgeons. Mean age was 63, 78% Caucasian, 10% African American, 6% Hispanic; with geographic distribution ranging from 10.8% Northwest to 29.5% Northeast. Initial consultation took place in-person for 94.8% and only 5.2% (89) occurred via video/telephone. To date, just over 1% (14) of patients tested positive for COVID-19. Mean invasive tumor size was 21.2mm and 15.7% were node positive. Of 1445 invasive breast cancers 75% (1081) were ER +/HER2-, 13.5% (195) HER2+, 11.1% (160) triple negative (TNBC) (9/missing data). DCIS comprised 18.2% (325) of the cohort. Of 267 cases of ER+ DCIS, 49% (131) had primary surgery and 49% (130) received NET. The majority of NET use was due to COVID-19, 95% (124). Almost all (50/52) ER- DCIS underwent primary surgery (6/missing ER). Table 1 describes the management for the 1436 patients with invasive cancer with known biomarkers. NET due to COVID-19 was utilized in 45% (482), with only 5% (54) as part of usual practice. Increasing age was not a statistically significant factor in the use of NET (OR 0.99, 95% CI 0.97-1.01). In comparison to patients from the Northwest, patients from the Southwest and Northeast had the greatest use of NET(COVID-19) vs NET(usual) (ORs 14.4 and 4.6) Genomic assay testing was performed on the core biopsy in 216 patients, with 65% (141) due to COVID-19. Among the patients who had genomic testing due to COVID-19, 116 (82%) had NET, 18 (13%) had NCT, with the remaining having primary surgery. Of 472 patients treated with primary surgery for which the impact of COVID-19 was provided, surgery was delayed in 20% (96). Patients from the Northeast had a 2.1 x greater odds of having surgery delayed in comparison to those from the Midwest. Patients also experienced changes to their surgical plan with the most common changes being 6% (27) converting from mastectomy to breast conservation and 7% (34) from mastectomy with reconstruction to mastectomy without reconstruction. Conclusion: COVID-19 led to significant modifications in breast cancer treatment, including high rates of NET, genomic assay testing on core biopsies as well as delays in surgery; each of which were consistent with the prioritization and treatment recommendations from the COVID-19 Pandemic Breast Cancer Consortium. The majority of patients with TNBC and HER2+ disease received guideline concordant NCT. The ASBrS Mastery COVID-19 registry provides a snapshot into the rapid care changes caused by the pandemic, has ongoing data entry and analysis and will enable understanding of the impact on long term breast cancer outcomes. Table 1: Biomarker specific treatmentsER+/HER2- (1081)TNBC (160)HER2+/any ER (195)Mean Age656159African American (%)97(9%)21(13%)27(14%)Primary Surgery (usual)386 (36%)50 (31%)37 (19%)Primary Surgery (COVID-19)28 (2.6%)6 (3.7%)6 (3.1%)NET (usual)54 (5%)NA1(0.5%)NET (COVID-19)482 (45%)NA6 (3.6%)NCT (usual)90 (8.3%)98 (61%)137 (70%)NCT (COVID-19)39 (3.6%)6 (3.7%)8 (4.1%) Citation Format: Lee Gravatt Wilke, Toan T Nguyen, Qiuyu Yang, Bret M Hanlon, Kathryn A Wagner, Pamela Strickland, Eric A Brown, Jill Dietz, Judy C Boughey. Impact of the COVID-19 pandemic on the multidisciplinary management of breast cancer: Initial analysis of the american society of breast surgeons mastery COVID-19 registry [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 SS2-01.
Role of axillary ultrasound after neoadjuvant chemotherapy in women with node-positive breast cancer (T1-4, N1-2, M0) at initial diagnosis (ACOSOG Z1071).
Le‐Petross, Huong T. , McCall, Linda, Ahrendt, Gretchen , Leitch, A. Marilyn , Taback, Bret , Hunt, Kelly K. , Mittendorf, EA , Wilke, Lee G. , Boughey, Judy C.

Journal of Clinical Oncology | March 11, 2020 | Volume: 30 | Issue: 15_suppl | Pages: 1107-1107

10.1200/jco.2012.30.15_suppl.1107 Get It

1107 Background: The role of axillary ultrasound (AUS) after neoadjuvant chemotherapy (NAC) to assess for residual nodal disease in patients presenting with node positive breast cancer remains unclear. ACOSOG Z1071 is a prospective multi-institutional trial evaluating sentinel node biopsy in patients with biopsy proven node positive breast cancer (T0-4, N1-2, M0) receiving NAC. Herein we report on the secondary objective evaluating the correlation of lymph node (LN) features on AUS with residual nodal disease. Methods: AUS images from diagnosis and after NAC were centrally reviewed for cortex size, LN size and LN morphology. Morphologic features were defined as: type I, no visible cortex, type II, < 3 mm hypoechoic cortex, type III, > 3mm hypoechoic cortex, type IV, generalized lobulated hypoechoic cortex, type V, focal hypoechoic cortical lobulation, and type VI, totally hypoechoic node with no hilum. Type I and II are considered normal. Results: Surgical and imaging data are available on 294 patients. Median age was 50 years (range 23-93 years), mean initial tumor size 3cm (0 to 15cm) and clinical stage II in 64.5% and III in 35.5%. The maximum LN diameter decreased after NAC (mean 22mm pre-NAC to 14mm post-NAC)(p<0.0001); however, there was no significant difference after NAC between the pathologically N+ (13mm, range 5-46mm) and N0 cases (12mm, range 3-32mm)(p=0.13). LN cortical thickness correlated with residual nodal disease after NAC (p-value = 0.04). Using a cutoff point of cortical thickness of 3 mm, the sensitivity was 33% (48/145) and specificity 80% (66/82). AUS morphological features after NAC was associated with false negative rate 62%, false positive rate 28%, sensitivity 38%, and specificity 72%. Conclusions: AUS after NAC is useful to assess nodal response. Cortical thickness was the best predictor of residual nodal metastasis. LN size and morphological features do not reliably exclude residual nodal metastasis in patients after NAC. [Table: see text]
Axillary Ultrasound Identifies Residual Nodal Disease After Chemotherapy: Results From the American College of Surgeons Oncology Group Z1071 Trial (Alliance)
Le‐Petross, Huong T. , McCall, Linda, Ahrendt, Gretchen , Wilke, Lee G., Wilke, Lee G. , Hunt, Kelly K. , Mittendorf, EA , Ballman, Karla V. , Boughey, Judy C.

American Journal of Roentgenology | January 30, 2018 | Volume: 210 | Issue: 3 | Pages: 669-676

10.2214/ajr.17.18295 Get It

A Phase II Trial of Neoadjuvant MK-2206, an AKT Inhibitor, with Anastrozole in Clinical Stage II or III PIK3CA -Mutant ER-Positive and HER2-Negative Breast Cancer
Cynthia, X. , Northfelt, Donald W. , Margenthaler, Julie A. , Aft, Rebecca , Gray, Richard J. , Wilke, Lee G. , Haddad, Tufia C. , Moynihan, Timothy J. , Loprinzi, Charles L. , Barnell, Erica K. , Skidmore, Zachary L. , Feng, Yan-Yang, Krysiak, Kilannin , Guo, Zhanfang , Nehring, Leslie, Wisinski, Kari B. , Sanati, Souzan , Al‐Kateb, Hussam , Griffith, Obi L. , Griffith, Malachi , Doyle, L. Austin, Erlichman, Charles , Suman, Vera, Northfelt, Donald, Haddad, Tufia, Moynihan, Timothy, Loprinzi, Charles, Hieken, Tina, Krysiak, Kilannin , Griffith, Malachi , Griffith, Obi L , Suman, Vera J. , Goetz, Matthew P. , Burkard, Mark E. , Ademuyiwa, Foluso O. , Naughton, Michael J. , Tevaarwerk, Amyé , Hieken, Tina J. , Hoog, Jeremy , Mardis, Elaine R. , Hagemann, Ian S. , Vij, Kiran R , Ellis, Matthew J.

Clinical Cancer Research | September 5, 2017 | Volume: 23 | Issue: 22 | Pages: 6823-6832

10.1158/1078-0432.ccr-17-1260 Get It

Abstract Purpose: Hyperactivation of AKT is common and associated with endocrine resistance in estrogen receptor–positive (ER+) breast cancer. The allosteric pan-AKT inhibitor MK-2206 induced apoptosis in PIK3CA-mutant ER+ breast cancer under estrogen-deprived condition in preclinical studies. This neoadjuvant phase II trial was therefore conducted to test the hypothesis that adding MK-2206 to anastrozole induces pathologic complete response (pCR) in PIK3CA mutant ER+ breast cancer. Experimental Design: Potential eligible patients with clinical stage II/III ER+/HER2− breast cancer were preregistered and received anastrozole (goserelin if premenopausal) for 28 days in cycle 0 pending tumor PIK3CA sequencing. Patients positive for PIK3CA mutation in the tumor were eligible to start MK-2206 (150 mg orally weekly, with prophylactic prednisone) on cycle 1 day 2 (C1D2) and to receive a maximum of four 28-day cycles of combination therapy before surgery. Serial biopsies were collected at preregistration, C1D1 and C1D17. Results: Fifty-one patients preregistered and 16 of 22 with PIK3CA-mutant tumors received study drug. Three patients went off study due to C1D17 Ki67 &gt;10% (n = 2) and toxicity (n = 1). Thirteen patients completed neoadjuvant therapy followed by surgery. No pCRs were observed. Rash was common. MK-2206 did not further suppress cell proliferation and did not induce apoptosis on C1D17 biopsies. Although AKT phosphorylation was reduced, PRAS40 phosphorylation at C1D17 after MK-2206 persisted. One patient acquired an ESR1 mutation at surgery. Conclusions: MK-2206 is unlikely to add to the efficacy of anastrozole alone in PIK3CA-mutant ER+ breast cancer and should not be studied further in the target patient population. Clin Cancer Res; 23(22); 6823–32. ©2017 AACR.
Abstract P5-13-04: A phase II neoadjuvant trial of MK-2206, an AKT inhibitor, in combination with anastrozole for clinical stage 2 or 3 PIK3CA mutant estrogen receptor positive HER2 negative (ER+HER2-) breast cancer (BC)
Ma, CX, Suman, VJ, Goetz, MP, Northfelt, DW, Naughton, MJ, Margenthaler, Julie A. , Aft, Rebecca , Tavaarwerk, A, Wilke, Lee G., Haddad, TC, Moynihan, T. J., Loprinzi, CL, Hieken, TJ, Guo, Zaipei , Han, Jialun , Sanati, Souzan , Al‐Kateb, Hussam , Doyle, L. , Erlichman, Charles , Ellis, MJ, Wilke, Lee G. , Burkard, Mark E. , Ademuyiwa, Foluso O. , Gray, Richard , Hoog, Jeremy , Guo, Z, Vij, Kiran R , Mardis, Elaine R.

Cancer Research | May 20, 2016 | Volume: 76 | Issue: 4_Supplement | Pages: P5-13-04-P5-13-04

10.1158/1538-7445.sabcs15-p5-13-04 Get It

Abstract Background Activating mutations in PIK3CA occur in approximately 40% ER+BC. MK-2206 (M), a pan-AKT inhibitor, induced apoptosis of ER+ BC under estrogen deprivation in preclinical studies. We conducted this neoadjuvant trial to determine the pathologic complete response (pCR) rate of M plus anastrozole (A) for PIK3CA mutant (Mut) ER+ BC. Methods This single arm open label study of M+A used a 2-stage Simon phase II design (stage 1, n=16; stage 2, n=13, alpha=0.10, power=0.90) to test whether pCR rate &lt;1% (based on historical data with A alone), against the alternative that pCR rate ≥15% in PIK3CA Mut ER+ BC. At least 1 pCR in stage 1 was required to proceed to stage 2. Eligible patients (pts) with clinical stage II or III ER+HER2- BC were pre-registered and proceeded to a research tumor biopsy for PIK3CA sequencing, followed by treatment with daily A monotherapy for 28 days (cycle 0). Pts with PIK3CA Mut BC were subsequently registered, underwent a second biopsy, and started M (150mg PO weekly) with daily A on cycle 1 day 1 (C1D1) for a maximum of four 28-day cycles followed by surgery. Goserelin was added for premenopausal pts. A tumor biopsy on C1D17, 17 days post the start of M, was performed. Those with C1D17 Ki67 &gt;10% discontinued study treatment. pCR was defined as no invasive cancer in the breast and the lymph nodes. Tumor specimens collected at all timepoints are being analyzed for markers of proliferation, apoptosis, and PI3K pathway activity, gene expression microarray, intrinsic subtypes, and next generation sequencing of 83 genes. Results Of the 51 pts pre-registered, 35 pts did not register due to no PIK3CA mutation (n=22), inadequate specimen for testing (n=6), physician/pt decision (n=7). The remaining 16 pts (median age: 58, range: 40-77 years) received combination therapy. Three pts did not complete 4 cycles due to C1D17 Ki67 &gt;10% (n=2) and intolerability (grade (Gr) 4 transaminase elevation in C1, n=1). Other severe toxicities possibly related to M included Gr 3 rash (25%) and pruritus (12.5%). Of the 13 pts completed study therapy and underwent surgery, all had residual disease in the breast and 7 also had positive nodes. Table 1 summarized changes in Ki67 during treatment. ComparisonsnAbsolute changes in Ki67 median (range)Wilcoxon signed rank p-valueC1D1 relative to pre-registration11-17.0% (-49.8 to 4.1%)0.0020C1D17 relative to pre-registration14-16.4% (-51.4 to 4.1%)0.0004C1D17 relative to C1D112-1.5% (-18.6 to 15.8%)0.9697C1D1, biopsy post 28 days of A alone; C1D17 biopsy post 17 days on combination therapy Although Ki67 levels post A monotherapy (C1D1) or M+A (C1D17) were significantly lower than that of pre-registration samples, Ki67 did not differ between C1D17 and C1D1 samples. Other correlative studies are ongoing and results will be presented. Conclusion Despite the small sample size, biomarker analysis on serial biopsy specimens demonstrated that M+A is unlikely to be more effective than A alone in PIK3CA Mut ER+ BC. This trial demonstrated the feasibility of genomic sequencing for pt selection and the value of a small, well-designed proof-of-principle neoadjuvant trial for the evaluation of targeted agents. Citation Format: Ma CX, Suman VJ, Goetz M, Northfelt D, Burkard M, Ademuyiwa F, Naughton M, Margenthaler J, Aft R, Gray R, Tavaarwerk A, Wilke L, Haddad T, Moynihan T, Loprinzi C, Hieken T, Hoog J, Guo Z, Han J, Vij K, Mardis E, Sanati S, Al-Kateb H, Doyle L, Erlichman C, Ellis MJ. A phase II neoadjuvant trial of MK-2206, an AKT inhibitor, in combination with anastrozole for clinical stage 2 or 3 PIK3CA mutant estrogen receptor positive HER2 negative (ER+HER2-) breast cancer (BC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-13-04.
Abstract P2-01-02: Methods impacting the false negative rate of sentinel lymph node surgery in patients presenting with node positive breast cancer (T0-T4,N1-2) who receive neoadjuvant chemotherapy – Results from a prospective trial – ACOSOG Z1071 (Allianc
Ballman, Karla V. , McCall, Linda, Ahrendt, Gretchen , Taback, Bret , Boughey, Judy C. , Symmans, W. Fraser , Mittendorf, EA , Wilke, Lee G. , Hunt, Kelly K. , Ballman, Karla

Cancer Research | May 4, 2015 | Volume: 75 | Issue: 9_Supplement | Pages: P2-01-02-P2-01-02

10.1158/1538-7445.sabcs14-p2-01-02 Get It

Abstract Background: The American College of Surgeons Oncology Group (ACOSOG) Z1071 trial (Alliance) reported a false negative rate (FNR) of 12.6% with sentinel lymph node (SLN) surgery after neoadjuvant chemotherapy in women presenting with node-positive breast cancer. Proposed methods to decrease the FNR include clip placement in the positive node at initial diagnosis with confirmation of resection of the clipped node at surgery and inclusion of residual metastatic cells identified by immunohistochemistry (IHC) for cytokeratins and disease measuring &lt;0.2mm on H&E in the definition of node positivity after chemotherapy. Herein we evaluate the impact of these methods on FNR. Methods: Z1071 was a prospective multi-institutional trial in which women with clinical T0-4,N1-2,M0 breast cancer underwent both SLN surgery and axillary dissection (ALND) after neoadjuvant chemotherapy. The primary endpoint defined nodal metastasis as disease &gt;0.2mm on H&E. Slides were submitted for central IHC staining when H&E-negative, unless performed locally. For this analysis, we expanded the definition of node positivity to include metastases less than 0.2mm on H&E and metastatic deposits identified by IHC. In 171 cases, a clip was placed in the node at initial biopsy and in these cases the SLNs and ALND were evaluated by x-ray or pathology to document clip location. FNR in the clip cohort is reported using the primary endpoint definition of node positive disease (&gt;0.2mm on H&E). Results: In the 113 cases where the clip was found in the SLN the FNR was 6.4% (1.8-15.5%). In the 29 cases where the clip was found in the ALND specimen, the FNR was 22.2% (6.4-47.6%). IHC was available on 470 of 525 patients with cN1 disease and 2 SLNs resected. Using the definition of H&E metastasis &gt;0.2mm, the FNR in these patients was 11.3% (34/301, 8.0-15.4%) which decreased to 8.7% (27/311, 5.6-11.8%) when including any disease &lt;0.2mm. SLNs from 16 patients had disease &lt;0.2mm in size. Seven patients previously classified as false negative SLN changed to true positive with identification of disease in the SLN. Nine patients changed from node-negative to node-positive with the only disease being &lt;0.2mm disease found in the SLN. Nodal pathologic complete response rate changed from 36.0% to 33.8% with the inclusion of metastases &lt;0.2mm. NResidual disease identified in SLNs or ALNDFNR (%)95% CINode positive definitionSLN metastases &gt;0.2mm by H&E470301 (64.0%)11.38.0-15.4SLN metastasis any size on IHC or H&E470311 (66.2%)8.75.6-11.8Clip locationClip in SLN11462 (54.4%)6.41.8-15.5Clip in ALND2918 (62.1%)22.26.4-47.6Clip location unknown2920 (69.0%)14.33.0-36.3Clip not placed354207 (58.5%)13.59.1-18.9 Conclusion: Placement of a clip at initial diagnosis of node positive disease with identification of the clip during the SLN surgery reduces the FNR. Use of IHC with inclusion of metastases &lt;0.2mm in the definition of residual nodal disease in women with node positive breast cancer after chemotherapy also improves the accuracy of SLN surgery. Use of one or both of these methods should be considered when performing SLN in this setting. Citation Format: Judy C Boughey, Karla V Ballman, William F Symmans, Linda M McCall, Elizabeth A Mittendorf, Gretchen M Ahrendt, Lee G Wilke, Bret Taback, Kelly K Hunt. Methods impacting the false negative rate of sentinel lymph node surgery in patients presenting with node positive breast cancer (T0-T4,N1-2) who receive neoadjuvant chemotherapy – Results from a prospective trial – ACOSOG Z1071 (Alliance) [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 P2-01-02.
Axillary Ultrasound After Neoadjuvant Chemotherapy and Its Impact on Sentinel Lymph Node Surgery: Results From the American College of Surgeons Oncology Group Z1071 Trial (Alliance)
McCall, Linda, Ahrendt, Gretchen , Wilke, Lee G. , Le‐Petross, Huong T. , Hunt, Kelly K. , McCall, Linda M, Mittendorf, Elizabeth A, Ahrendt, Gretchen M, Le-Petross, Huong T, Boughey, Judy C. , Ballman, Karla V. , Mittendorf, EA

Journal of Clinical Oncology | February 2, 2015 | Volume: 33 | Issue: 30 | Pages: 3386-3393

10.1200/jco.2014.57.8401 Get It

Purpose The American College of Surgeons Oncology Group Z1071 trial reported a 12.6% false-negative rate (FNR) for sentinel lymph node (SLN) surgery after neoadjuvant chemotherapy (NAC) in cN1 disease. Patients were not selected for surgery based on response, but a secondary end point was to determine whether axillary ultrasound (AUS) after NAC after fine-needle aspiration cytology can identify abnormal nodes and guide patient selection for SLN surgery. Patients and Methods Patients with T0-4, N1-2, M0 breast cancer underwent AUS after neoadjuvant chemotherapy. AUS images were centrally reviewed and classified as normal or suspicious lymph nodes. AUS findings were tested for association with pathologic nodal status and SLN FNR. The impact of AUS results to select patients for SLN surgery to reduce the FNR was assessed. Results Postchemotherapy AUS images were reviewed for 611 patients. One hundred thirty (71.8%) of 181 AUS-suspicious patients were node positive at surgery compared with 243 (56.5%) of 430 AUS-normal patients (P < .001). Patients with AUS-suspicious nodes had a greater number of positive nodes and greater metastasis size (P < .001). The SLN FNR was not different based on AUS results; however, using a strategy where only patients with normal AUS undergo SLN surgery would potentially reduce the FNR in Z1071 patients with ≥ two SLNs removed from 12.6% to 9.8% when preoperative AUS results are considered as part of SLN surgery. Conclusion AUS is recommended after chemotherapy to guide axillary surgery. An FNR of 9.8% with the combination of AUS and SLN surgery would be acceptable for the adoption of SLN surgery for women with node-positive breast cancer treated with neoadjuvant chemotherapy.
Abstract S2-1: The role of sentinel lymph node surgery in patients presenting with node positive breast cancer (T0-T4, N1-2) who receive neoadjuvant chemotherapy – results from the ACOSOG Z1071 trial
Boughey, JC , Suman, VJ, Mittendorf, EA , Ahrendt, GM, Wilke, LG, Taback, Bret , Leitch, A. Marilyn , Flippo-Morton, TS, Byrd, D., Ollila, DW, Julian, TB, McLaughlin, SA, McCall, Lisa, Symmans, WF, Le-Petross, HT, Haffty, BG, Buchholz, TA, Hunt, KK, Wilke, Lee G.

Cancer Research | August 14, 2014 | Volume: 72 | Issue: 24_Supplement | Pages: S2-1-S2-1

10.1158/0008-5472.sabcs12-s2-1 Get It

Abstract Background: The utility of sentinel lymph node (SLN) surgery after neoadjuvant chemotherapy (NAC) in patients presenting with node-positive breast cancer has not been determined. The American College of Surgeons Oncology Group (ACOSOG) Z0171 trial was designed to evaluate SLN surgery after NAC in women presenting with node positive disease. Methods: ACOSOG Z1071 enrolled women with clinical T0-4, N1-2, M0 breast cancer receiving NAC. At the time of surgery, all patients were to undergo SLN surgery followed by axillary lymph node dissection (ALND). The primary endpoint was false negative rate (FNR) in women with cN1 disease with 2 or more SLNs reviewed. Positive SLNs were defined as metastases &gt;0.2mm on H&E. The protocol encouraged dual tracer technique. A Bayesian study design with a non-informative prior was chosen to assess whether the probability that the SLN surgery FNR is greater than 10%. Results: From July 2009 to July 2011, 756 patients were enrolled from 136 institutions. Fifteen women were ineligible and 33 withdrew. Of 708 evaluable pts (668 cN1, 40 cN2), 643 had a SLN identified and an ALND (607 cN1, with indeterminate SLN results in 2); 52 pts (48 cN1) had no SLN identified and had ALND; 11 underwent ALND only (all cN1), and 2 pts had SLN only (both cN1). In patients with SLN and ALND, the SLN identification rate was 92.5% (92.7% in cN1, 90% in cN2). SLN correctly identified nodal status in 84% of the 695 pts [258 of pathologically node negative and 327 of pathologically node positive; cN1: 83.8% (549/655), cN2: 90.0% (36/40)]. Of the 643 pts with a SLN identified there was a complete pathologic response in 40.3% (40.3 % for cN1 and 50% for cN2). Of the pts with a positive SLN, the SLN was the only site of disease in 40%. For pts with cN1 disease with 2+ SLNs identified with residual nodal disease, the SLN FNR was 12.8%. In pts with dual tracer technique the FNR was 11.1%. There were no FN results among pts with cN2 disease with 2+ SLNs reviewed. Of the 40 pts with a false negative SLN of the 528 cN1 patients with 2+ SLNs examined, the number of positive nodes at ALND was 1 (50.0%); 2 (25%); 3 (10.0%) and 4–9 (15.0%). Conclusions: NAC resulted in eradication of lymph node disease in 40% of node positive breast cancer patients. SLN surgery after NAC in node positive breast cancer pts correctly identified nodal status in 84% of all patients and was associated with a FNR of 12.8%. The FNR of SLN is higher than the prespecified study endpoint of 10%. Further analysis of factors associated with FNR such as clinical response, histological findings and axillary ultrasound findings is warranted prior to widespread use of SLN in these patients. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S2-1.