The use of sentinel lymph node surgery after neoadjuvant chemotherapy for patients who present with cN1 breast cancer provides an opportunity to avoid axillary lymph node dissection for those patients who have eradication of their nodal disease with chemotherapy. Since the initial publication of prospective trials demonstrating the false-negative rate of sentinel lymph node (SLN) surgery in this setting, this practice has been increasing. [1][2][3][4] A recent survey of the American Society of Breast Surgeons (ASBrS) reported that 85% of respondents offered SLN surgery to some patients in this setting. 5

This study provides a prospective assessment of the sentinel lymph node biopsy procedure, as performed by a wide range of surgeons, demonstrating a low complication rate.

The blockbuster chemotherapy drug paclitaxel is widely presumed to cause cell death in tumors as a consequence of mitotic arrest, as it does at concentrations routinely used in cell culture. However, we determine here that paclitaxel levels in primary breast tumors are well below those required to elicit sustained mitotic arrest. Instead, cells in these lower concentrations of drug proceed through mitosis without substantial delay and divide their chromosomes on multipolar spindles, resulting in chromosome missegregation and cell death. Consistent with these cell culture data, the majority of mitotic cells in primary human breast cancers contain multipolar spindles after paclitaxel treatment. Contrary to the previous hypothesis, we find that mitotic arrest is dispensable for tumor regression in patients. These results demonstrate that mitotic arrest is not responsible for the efficacy of paclitaxel, which occurs due to chromosome missegregation on highly abnormal, multipolar spindles. This mechanistic insight may be used to improve selection of future anti-mitotic drugs and to identify a biomarker with which to select patients likely to benefit from paclitaxel.

Background The American College of Surgeons Oncology Group Z1071 trial 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. One proposed method to decrease the FNR is clip placement in the positive node at initial diagnosis with confirmation of clipped node resection at surgery. Methods Z1071 was a multi-institutional trial in which women with clinical T0-4,N1-2,M0 breast cancer underwent SLN surgery and axillary dissection (ALND) after neoadjuvant chemotherapy. In cases with a clip placed in the node, the clip location at surgery (SLN or ALND) was evaluated. Results A clip was placed at initial node biopsy in 203 patients. In the 170 (83.7%) patients with cN1 disease and at least 2 SLNs resected, clip location was confirmed in 141 cases. In 107 (75.9%) patients where the clipped node was within the SLN specimen, the FNR was 6.8% (CI:1.9–16.5%). In 34 (24.1%) cases where the clipped node was in the ALND specimen, the FNR was 19.0% (CI:5.4–41.9%). In cases without a clip placed (n=355) and those where clipped node location was not confirmed at surgery (n=29), the FNR was 13.4% and 14.3%, respectively. Conclusion Clip placement at diagnosis of node-positive disease with removal of the clipped node during SLN surgery reduces the FNR of SLN surgery after neoadjuvant chemotherapy. Clip placement in the biopsy-proven node at diagnosis and evaluation of resected specimens for the clipped node should be considered when performing SLN surgery in this setting.

Objective To determine the impact of tumor biology on rates of breast-conserving surgery and pathologic complete response (pCR) after neoadjuvant chemotherapy. Summary Background Data The impact of tumor biology on the rate of breast-conserving surgery after neoadjuvant chemotherapy has not been well studied. Methods We used data from ACOSOG Z1071, a prospective, multicenter study assessing sentinel node surgery after neoadjuvant chemotherapy in patients presenting with node-positive breast cancer from 2009 through 2011, to determine rates of breast-conserving surgery and pCR after chemotherapy by approximated biologic subtype. Results Of the 756 patients enrolled on Z1071, 694 had findings available from pathologic review of breast and axillary specimens from surgery after chemotherapy. Approximated subtype was triple-negative in 170 (24.5%) patients, HER2-positive in 207 (29.8%), and hormone-receptor-positive, HER2-negative in 317 (45.7%). Patient age and clinical tumor and nodal stage at presentation did not differ across subtypes. Rates of breast-conserving surgery were significantly higher in patients with triple-negative (46.8%) and HER2-positive tumors (43.0%) than in those with hormone-receptor-positive, HER2-negative tumors (34.5%) (P = 0.019). Rates of pCR in both the breast and axilla were 38.2% in triple-negative, 45.4% in HER2-positive, and 11.4% in hormone-receptor-positive, HER2-negative disease (P < 0.0001). Rates of pCR in the breast only and the axilla only exhibited similar differences across tumor subtypes. Conclusions Patients with triple-negative and HER2-positive breast cancers have the highest rates of breast-conserving surgery and pCR after neoadjuvant chemotherapy. Patients with these subtypes are most likely to be candidates for less invasive surgical approaches after chemotherapy.

Aerobic exercise training (AET) is an effective adjunct therapy to attenuate the adverse side-effects of adjuvant chemotherapy in women with early breast cancer. Whether AET interacts with the antitumor efficacy of chemotherapy has received scant attention. We carried out a pilot study to explore the effects of AET in combination with neoadjuvant doxorubicin–cyclophosphamide (AC+AET), relative to AC alone, on: (i) host physiology [exercise capacity (VO2 peak), brachial artery flow-mediated dilation (BA-FMD)], (ii) host-related circulating factors [circulating endothelial progenitor cells (CEP) cytokines and angiogenic factors (CAF)], and (iii) tumor phenotype [tumor blood flow (15O–water PET), tissue markers (hypoxia and proliferation), and gene expression] in 20 women with operable breast cancer. AET consisted of three supervised cycle ergometry sessions/week at 60% to 100% of VO2 peak, 30 to 45 min/session, for 12 weeks. There was significant time × group interactions for VO2 peak and BA-FMD, favoring the AC+AET group (P < 0.001 and P = 0.07, respectively). These changes were accompanied by significant time × group interactions in CEPs and select CAFs [placenta growth factor, interleukin (IL)-1β, and IL-2], also favoring the AC+AET group (P < 0.05). 15O–water positron emission tomography (PET) imaging revealed a 38%decrease in tumor blood flow in the AC+AET group. There were no differences in any tumor tissue markers (P > 0.05). Whole-genome microarray tumor analysis revealed significant differential modulation of 57 pathways (P < 0.01), including many that converge on NF-κB. Data from this exploratory study provide initial evidence that AET can modulate several host- and tumor-related pathways during standard chemotherapy. The biologic and clinical implications remain to be determined.

Background Achieving negative surgical margins is critical to minimizing the risk of tumor recurrence in patients undergoing breast conservation surgery (BCS) for a breast malignancy. Our objective was to perform a systematic review comparing reexcision rates, sensitivity and specificity of the intraoperative use of the margin assessment techniques of imprint cytology (IC) and frozen section analysis (FSA), against permanent histopathologic section (PS). Methods The databases PubMed, Web of Knowledge, Cochrane Library and CINAHL Plus were searched for literature published from 1997 to 2011. Original investigations of patients who underwent BCS for breast cancer that evaluated margin assessment with PS and/or IC or FSA were included. Of 182 titles identified, 41 patient cohorts from 37 articles met inclusion criteria: PS (n = 19), IC (n = 7) and FSA (n = 15). Studies were summarized qualitatively using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for cohort studies and the Strength of Recommendation Taxonomy (SORT) numerical scale for diagnostic studies. Results The final reexcision rates after primary BCS were 35 % for PS, 11 % for IC (p = 0.001 vs. PS) and 10 % for FSA (p < 0.0001 vs. PS). For IC, reexcision rates decreased from 26 to 4 % (p = 0.18) and for FSA, reexcision rates decreased from 27 to 6 % (p < 0.0001). The pooled sensitivity of IC and FSA were 72 and 83 %. The pooled specificity of IC and FSA were 97 and 95 %. The average length of each technique was 13 min for IC and 27 min for FSA. Conclusions Patients who underwent BCS with intraop-erative IC or FSA to assess negative surgical margins had significantly fewer secondary surgical procedures for excision of their breast malignancies.

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.