Citations

Purpose The seventh edition of the American Joint Committee on Cancer (AJCC) staging system for breast cancer differentiates patients with T1 tumors and lymph node micrometastases (stage IB) from patients with T1 tumors and negative nodes (stage IA). This study was undertaken to determine the utility of the stage IB designation. Patients and Methods The following two cohorts of patients with breast cancer were identified: 3,474 patients treated at The University of Texas MD Anderson Cancer Center from 1993 to 2007 and 4,590 patients from the American College of Surgeons Oncology Group (ACOSOG) Z0010 trial. Clinicopathologic and outcomes data were recorded, and disease was staged according to the seventh edition AJCC staging system. Recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were determined using the Kaplan-Meier method and compared using the log-rank test. Results Median follow-up times were 6.1 years and 9.0 years for the MD Anderson Cancer Center and ACOSOG cohorts, respectively. In both cohorts, there were no significant differences between patients with stage IA and stage IB disease in 5- or 10-year RFS, DSS, or OS. Estrogen receptor (ER) status and grade significantly stratified patients with stage I disease with respect to RFS, DSS, and OS. Conclusion Among patients with T1 breast cancer, individuals with micrometastases and those with negative nodes have similar survival outcomes. ER status and grade are better discriminants of survival than the presence of small-volume nodal metastases. In preparing the next edition of the AJCC staging system, consideration should be given to eliminating the stage IB designation and incorporating biologic factors.

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 >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.

Abstract Purpose: The stage IB designation was added to the AJCC 7th edition staging system to denote micrometastasis in patients with T1 tumors. We have previously examined this group and found that receptor status and nuclear grade were better survival discriminates than the presence of micrometastases. The current study was undertaken to validate this finding in a larger cohort from the American College of Surgeons Oncology Group (ACOSOG) Z0010 study. Methods: Clinicopathologic and outcomes data from patients enrolled on ACOSOG Z0010 were recorded. All patients underwent breast conserving surgery, sentinel lymph node biopsy and whole breast radiation for clinical T1-2, N0 breast cancer. Sentinel lymph nodes were evaluated by H&E locally and if negative, by immunohistochemistry (IHC) at a central laboratory. Patients were staged according to the 7th edition AJCC system and recurrence-free (RFS), disease-specific (DSS) and overall survival (OS) were determined using the Kaplan-Meier method and compared using the log-rank test. Results: There were 5210 eligible and evaluable patients enrolled on ACOSOG Z0010. AJCC stage distribution was known in 4590 and included: 2849 (62.0%) stage IA, 376 (8.2%) stage IB, 878 (19.1%) stage IIA, 322 (7.0%) stage IIB, and 170 (3.7%) stage III. Median follow-up for the cohort was 9.0 years (range 0–12.6). Five and 10-year RFS, DSS and OS rates for patients with stage IA versus IB disease are shown in table 1. There were no significant differences between groups. When all stage I patients (stage IA and IB) were evaluated by ER status (positive vs negative) or grade (grade 1 vs 2 vs 3), these biologic factors were able to significantly discriminate patients with respect to RFS, DSS and OS (table 2). Conclusion: Differentiating patients with micrometastases (stage IB) from node negative patients (stage IA) does not stratify patients well with respect to survival. Biologic factors including ER status and grade are better discriminants of survival than the presence of small volume nodal metastases in patients with early stage breast cancer. Breast cancer staging should include biologic factors from the primary tumor. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-06.

Abstract Early-phase trials targeting the T-cell inhibitory molecule programmed cell death ligand 1 (PD-L1) have shown clinical efficacy in cancer. This study was undertaken to determine whether PD-L1 is overexpressed in triple-negative breast cancer (TNBC) and to investigate the loss of PTEN as a mechanism of PD-L1 regulation. The Cancer Genome Atlas (TCGA) RNA sequencing data showed significantly greater expression of the PD-L1 gene in TNBC (n = 120) compared with non-TNBC (n = 716; P < 0.001). Breast tumor tissue microarrays were evaluated for PD-L1 expression, which was present in 19% (20 of 105) of TNBC specimens. PD-L1+ tumors had greater CD8+ T-cell infiltrate than PD-L1− tumors (688 cells/mm vs. 263 cells/mm; P < 0.0001). To determine the effect of PTEN loss on PD-L1 expression, stable cell lines were generated using PTEN short hairpin RNA (shRNA). PTEN knockdown led to significantly higher cell-surface PD-L1 expression and PD-L1 transcripts, suggesting transcriptional regulation. Moreover, phosphoinositide 3-kinase (PI3K) pathway inhibition using the AKT inhibitor MK-2206 or rapamycin resulted in decreased PD-L1 expression, further linking PTEN and PI3K signaling to PD-L1 regulation. Coculture experiments were performed to determine the functional effect of altered PD-L1 expression. Increased PD-L1 cell surface expression by tumor cells induced by PTEN loss led to decreased T-cell proliferation and increased apoptosis. PD-L1 is expressed in 20% of TNBCs, suggesting PD-L1 as a therapeutic target in TNBCs. Because PTEN loss is one mechanism regulating PD-L1 expression, agents targeting the PI3K pathway may increase the antitumor adaptive immune responses. Cancer Immunol Res; 2(4); 361–70. ©2014 AACR.

Abstract Purpose: Emerging data from cooperative group trials suggests that not all patients with a positive SLN require completion axillary lymph node dissection (ALND). The controversy regarding who will benefit from additional nodal clearance continues, suggesting a need for improved tools to predict non-SLN involvement. We hypothesized that the size of a SLN metastasis evaluated as a continuous variable would be an important predictor of non-SLN involvement. The goal of this study was to determine clinicopathologic factors including SLN metastasis size that predicted non-SLN involvement and to use these factors to construct an improved predictive nomogram. Methods: Using a prospective database, we identified 509 patients with invasive breast cancer from 1996 - 2007 with a positive SLN who underwent ALND. Patients receiving neoadjuvant therapy were excluded. Clinicopathologic data including age, primary tumor size, presence of multifocal disease, histology (invasive ductal vs. invasive lobular vs. mixed invasive), tumor grade, estrogen receptor, progesterone receptor, and HER2/neu status, presence of lymphovascular invasion (LVI), the number of SLNs identified, number of positive SLNs, the maximum SLN metastasis size and the presence of extranodal extension were recorded. For SLNs described only as containing isolated tumor cells, size was recorded as 0.1 mm. Univariate and multivariate logistic regression analyses were performed to identify factors predictive of positive non-SLNs. Using these variables, a nomogram was constructed and subsequently validated using an external cohort of 464 patients. Results: On univariate analysis, the following factors were predictive of positive non-SLNs: number of SLN identified (p<.001), number of positive SLN (p<.001), maximum SLN metastasis size (p<.001), extranodal extension (p<.001), primary tumor size (p=.001), LVI (p=.019) and histology (p=.034). On multivariate analysis, all factors remained significant at the 5% level except LVI. A nomogram was created using these variables. When applied to an external cohort, the nomogram was accurate and discriminating with an area under the receiver operating characteristic curve of .73 (95% CI: .68 - .77). Conclusions: SLN metastasis size is predictive for identifying additional disease in the axilla. These data have been incorporated into a nomogram that accurately predicts the likelihood of having additional, non-SLN metastasis suggesting that routine reporting of the SLN metastasis size would assist with clinical decision making regarding the need to perform a completion ALND. Figures available in online version. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD06-08.