Elizabeth A. Mittendorf

Sentinel Lymph Node Surgery After Neoadjuvant Chemotherapy in Patients With Node-Positive Breast Cancer The ACOSOG Z1071 (Alliance) Clinical Trial

IMPORTANCE Sentinel lymph node (SLN) surgery provides reliable nodal staging information with less morbidity than axillary lymph node dissection (ALND) for patients with clinically node-negative (cN0) breast cancer. The application of SLN surgery for staging the axilla following chemotherapy for women who initially had node-positive cN1 breast cancer is unclear because of high false-negative results reported in previous studies. OBJECTIVE To determine the false-negative rate (FNR) for SLN surgery following chemotherapy in women initially presenting with biopsy-proven cN1 breast cancer. DESIGN, SETTING, AND PATIENTS The American College of Surgeons Oncology Group (ACOSOG) Z1071 trial enrolled women from 136 institutions from July 2009 to June 2011 who had clinical T0 through T4, N1 through N2, M0 breast cancer and received neoadjuvant chemotherapy. Following chemotherapy, patients underwent both SLN surgery and ALND. Sentinel lymph node surgery using both blue dye (isosulfan blue or methylene blue) and a radiolabeled colloid mapping agent was encouraged. MAIN OUTCOMES AND MEASURES The primary end point was the FNR of SLN surgery after chemotherapy in women who presented with cN1 disease. We evaluated the likelihood that the FNR in patients with 2 or more SLNs examined was greater than 10%, the rate expected for women undergoing SLN surgery who present with cN0 disease. RESULTS Seven hundred fifty-six women were enrolled in the study. Of 663 evaluable patients with cN1 disease, 649 underwent chemotherapy followed by both SLN surgery and ALND. An SLN could not be identified in 46 patients (7.1%). Only 1 SLN was excised in 78 patients (12.0%). Of the remaining 525 patients with 2 or more SLNs removed, no cancer was identified in the axillary lymph nodes of 215 patients, yielding a pathological complete nodal response of 41.0% (95% CI, 36.7%-45.3%). In 39 patients, cancer was not identified in the SLNs but was found in lymph nodes obtained with ALND, resulting in an FNR of 12.6% (90% Bayesian credible interval, 9.85%-16.05%). CONCLUSIONS AND RELEVANCE Among women with cN1 breast cancer receiving neoadjuvant chemotherapy who had 2 or more SLNs examined, the FNR was not found to be 10% or less. Given this FNR threshold, changes in approach and patient selection that result in greater sensitivity would be necessary to support the use of SLN surgery as an alternative to ALND. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00881361.

PD-L1 Expression in Triple-Negative Breast Cancer

Using tissue microarrays containing 105 triple-negative breast cancer (TNBC) specimens, Mittendorf and colleagues show that 20% of the TNBC specimens express PD-L1, half have lost PTEN, and inhibitors of PI3K pathway decrease PD-L1 expression, providing a rationale for therapeutic targeting of PD-L1 for TNBC. 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.

Loss of Human Epidermal Growth Factor Receptor 2 (HER2) Expression in Metastatic Sites of HER2-Overexpressing Primary Breast Tumors

PURPOSE We evaluated whether patients with human epidermal growth factor receptor 2 (HER2) -positive primary breast tumors had metastatic tumors that were HER2 positive (concordant) or HER2 negative (discordant). We then evaluated whether treatment with trastuzumab or chemotherapy before biopsy of the metastasis had any effect on the rate of HER2 discordance. We also compared the overall survival durations of patients with HER2-concordant and -discordant tumors. PATIENTS AND METHODS We retrospectively identified all patients who initially had been diagnosed with HER2-positive (immunohistochemistry 3+ and/or fluorescent in situ hybridization positive) primary breast cancer between 1997 and 2008 at MD Anderson Cancer Center who also had metastatic tumor biopsy results available for review. RESULTS We included 182 patients who met our criteria. Forty-three (24%) of the 182 patients with HER2-positive primary tumors had HER2-negative metastatic tumors. The HER2 discordance rates differed significantly on the basis of whether patients received chemotherapy (P = .022) but not on the basis of whether patients received trastuzumab (P = .296). Patients with discordant HER2 status had shorter overall survival than did patients with concordant HER2 status (hazard ratio [HR], 0.43; P = .003). A survival difference remained among the 67 patients who received trastuzumab (HR, 0.56; P = .083) and 101 patients who did not (HR, 0.53; P = .033) before their metastasis biopsies. CONCLUSION We confirmed that loss of HER2-positive status in metastatic tumors can occur in patients with primary HER2-positive breast cancer. Our data strongly support the need for biopsies of metastatic lesions to accurately determine patient prognosis and appropriate use of targeted therapy.

Sentinel lymph node surgery after neoadjuvant chemotherapy is accurate and reduces the need for axillary dissection in breast cancer patients

Objective:Sentinel lymph node (SLN) surgery is widely used for nodal staging in early-stage breast cancer. This study was performed to evaluate the accuracy of SLN surgery for patients undergoing neoadjuvant chemotherapy versus patients undergoing surgery first. Summary Background Data:Controversy exists regarding the timing of SLN surgery in patients planned for neoadjuvant chemotherapy. Proponents of SLN surgery after chemotherapy prefer a single surgical procedure with potential for fewer axillary dissections. Opponents cite early studies with low identification rates and high false-negative rates after chemotherapy. Methods:A total of 3746 patients with clinically node negative T1-T3 breast cancer underwent SLN surgery from 1994 to 2007. Clinicopathologic data were reviewed and comparisons made between patients receiving neoadjuvant chemotherapy and those undergoing surgery first. Results:Of the patients, 575 (15.3%) underwent SLN surgery after chemotherapy and 3171 (84.7%) underwent surgery first. Neoadjuvant patients were younger (51 vs. 57 years, P < 0.0001) and had more clinical T2-T3 tumors (87.3% vs. 18.8%, P < 0.0001) at diagnosis. SLN identification rates were 97.4% in the neoadjuvant group and 98.7% in the surgery first group (P = 0.017). False-negative rates were similar between groups (5/84 [5.9%] in neoadjuvant vs. 22/542 [4.1%] in the surgery first group, P = 0.39). Analyzed by presenting T stage, there were fewer positive SLNs in the neoadjuvant group (T1: 12.7% vs. 19.0%, P = 0.2; T2: 20.5% vs. 36.5%, P < 0.0001; T3: 30.4% vs. 51.4%, P = 0.04). Adjusting for clinical stage revealed no differences in local-regional recurrences, disease-free or overall survival between groups. Conclusions:SLN surgery after chemotherapy is as accurate for axillary staging as SLN surgery prior to chemotherapy. SLN surgery after chemotherapy results in fewer positive SLNs and decreases unnecessary axillary dissections.

Loss of HER2 amplification following trastuzumab-based neoadjuvant systemic therapy and survival outcomes.

Purpose: To evaluate HER2 status in residual tumor identified at the time of surgery in patients not achieving a pathologic complete response (pCR) and to determine the effect of alterations in HER2 status on recurrence-free survival (RFS). Experimental Design: Clinicopathologic data for patients with HER2-overexpressing breast cancer receiving neoadjuvant therapy with a taxane, anthracycline, and concomitant trastuzumab between 2004 and 2007 were reviewed. Surgical specimens for patients achieving less than a pCR were assessed to determine if there was enough residual tissue to evaluate posttreatment HER2 status. RFS was determined using the Kaplan-Meier method and compared by the log-rank statistic. Results: A pCR was achieved in 72 of the 142 (50.7%) patients. Residual tumor was sufficient to assess posttreatment HER2 status in 25 patients. Fluorescence in situ hybridization done on pretreatment specimens confirmed HER2 amplification before beginning therapy. Eight (32.0%) posttreatment tumors were found to be HER2-negative by fluorescence in situ hybridization. At a median follow-up of 37 months (range, 8-56 months), the RFS was significantly better for patients with tumors that retained HER2 amplification (87.5% versus 50%, P = 0.04). Conclusion: High pCR rates are achieved in patients with HER2-positive breast cancer treated with neoadjuvant trastuzumab in combination with anthracyclines and taxanes. One third of patients with significant residual disease loses HER2 amplification, and this change is associated with poor RFS. Residual tumor identified at the time of surgery should be reassessed for HER2 status, and novel adjuvant therapy strategies need to be studied in this population. (Clin Cancer Res 2009;15(23):7381–8)

Improved Axillary Evaluation Following Neoadjuvant Therapy for Patients With Node-Positive Breast Cancer Using Selective Evaluation of Clipped Nodes: Implementation of Targeted Axillary Dissection

PURPOSE Placing clips in nodes with biopsy-confirmed metastasis before initiating neoadjuvant therapy allows for evaluation of response in breast cancer. Our goal was to determine if pathologic changes in clipped nodes reflect the status of the nodal basin and if targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of clipped nodes, improves the false-negative rate (FNR) compared with SLND alone. METHODS A prospective study of patients with biopsy-confirmed nodal metastases with a clip placed in the sampled node was performed. After neoadjuvant therapy, patients underwent axillary surgery and the pathology of the clipped node was compared with other nodes. Patients undergoing TAD had SLND and selective removal of the clipped node using iodine-125 seed localization. The FNR was determined in patients undergoing complete axillary lymphadenectomy (ALND). RESULTS Of 208 patients enrolled in this study, 191 underwent ALND, with residual disease identified in 120 (63%). The clipped node revealed metastases in 115 patients, resulting in an FNR of 4.2% (95% CI, 1.4 to 9.5) for the clipped node. In patients undergoing SLND and ALND (n = 118), the FNR was 10.1% (95% CI, 4.2 to 19.8), which included seven false-negative events in 69 patients with residual disease. Adding evaluation of the clipped node reduced the FNR to 1.4% (95% CI, 0.03 to 7.3; P = .03). The clipped node was not retrieved as an SLN in 23% (31 of 134) of patients, including six with negative SLNs but metastasis in the clipped node. TAD followed by ALND was performed in 85 patients, with an FNR of 2.0% (1 of 50; 95% CI, 0.05 to 10.7). CONCLUSION Marking nodes with biopsy-confirmed metastatic disease allows for selective removal and improves pathologic evaluation for residual nodal disease after chemotherapy.

Combined Clinical Trial Results of a HER2/neu (E75) Vaccine for the Prevention of Recurrence in High-Risk Breast Cancer Patients: U.S. Military Cancer Institute Clinical Trials Group Study I-01 and I-02

Purpose: E75 is an immunogenic peptide from the HER2/neu protein, which is overexpressed in many breast cancer patients. We have conducted two overlapping E75 vaccine trials to prevent recurrence in node-positive (NP) and node-negative (NN) breast cancer patients. Experimental Design: E75 (HER2/neu 369-377) + granulocyte macrophage colony-stimulating factor was given intradermally to previously treated, disease-free NP breast cancer patients in a dose escalation safety trial and to NN breast cancer patients in a dose optimization study. Local and systemic toxicity was monitored. Immunologic responses were assessed using in vitro assays and in vivo delayed-type hypersensitivity responses. Clinical recurrences were documented. Results: One hundred and eighty-six patients were enrolled in the two studies (NP, 95; NN, 91). Human leucocyte antigen A2 (HLA-A2) and HLA-A3 patients were vaccinated (n = 101), whereas all others (n = 85) were followed prospectively as controls. Toxicities were minimal, and a dose-dependent immunologic response to the vaccine was shown. Planned primary analysis revealed a recurrence rate of 5.6% in vaccinated patients compared with 14.2% in the controls (P = 0.04) at a median of 20 months follow-up. As vaccine-specific immunity waned over time, the difference in recurrence lost significance at 26 months median follow-up (8.3% versus 14.8%); however, a significant difference in the pattern of recurrence persisted. Conclusions: E75 is safe and effective in raising a dose-dependent HER2/neu immunity in HLA-A2 and HLA-A3 NP and NN breast cancer patients. More importantly, E75 may reduce recurrences in disease-free, conventionally treated, high-risk breast cancer patients. These findings warrant a prospective, randomized phase III trial of the E75 vaccine with periodic booster to prevent breast cancer recurrences.

Combined Use of Clinical and Pathologic Staging Variables to Define Outcomes for Breast Cancer Patients Treated With Neoadjuvant Therapy

PURPOSE Neoadjuvant chemotherapy is being used with increasing frequency for operable breast cancer. We hypothesized that by using clinical and pathologic staging parameters, in conjunction with biologic tumor markers, a novel means of determining prognosis for patients treated with neoadjuvant chemotherapy could be facilitated. PATIENTS AND METHODS A prospective database of patients treated with neoadjuvant chemotherapy from 1997 to 2003 was reviewed, and 932 patients meeting inclusion criteria were identified. Clinical and pathologic tumor characteristics, treatment regimens, and patient outcomes were recorded. Cox proportional hazards models were used to create two prognostic scoring systems. American Joint Committee on Cancer (AJCC) clinical and pathologic staging parameters and biologic tumor markers were investigated to devise the scoring systems. RESULTS Median follow-up time was 5 years (range, 0.4 to 9.4 years). Five-year disease-specific survival rate was 96% for patients who experienced a pathologic complete response (pCR; n = 130) compared with 87% for patients who did not have a pCR (n = 802; P = .001). Two scoring systems, based on summing binary indicators for clinical substages >/= IIB and >/= IIIB, pathologic substages >/= ypIIA and >/= ypIIIC, negative estrogen receptor status, and grade 3 pathology, were devised to predict 5-year patient outcomes. These scoring systems facilitated separation of the study population into more refined subgroups by outcome than the current AJCC staging system. CONCLUSION The scoring systems derived in this work provide a novel means for evaluating prognosis after neoadjuvant therapy. Future work will focus on prospective validation of these scoring systems and refinement of the scoring systems through addition of new biologic markers.

Clinical trial results of the HER-2/neu (E75) vaccine to prevent breast cancer recurrence in high-risk patients: from US Military Cancer Institute Clinical Trials Group Study I-01 and I-02.

The authors conducted exploratory phase 1‐2 clinical trials vaccinating breast cancer patients with E75, a human leukocyte antigen (HLA) A2/A3–restricted HER‐2/neu (HER2) peptide, and granulocyte‐macrophage colony‐stimulating factor. The vaccine is given as adjuvant therapy to prevent disease recurrence. They previously reported that the vaccine is safe and effective in stimulating expansion of E75‐specific cytotoxic T cells. Here, they report 24‐month landmark analyses of disease‐free survival (DFS).

Multidisciplinary considerations in the implementation of the findings from the American College of Surgeons Oncology Group (ACOSOG) Z0011 study: a practice-changing trial.

Surgical management of breast cancer has evolved from routine use of radical mastectomy to less disfiguring and extensive procedures, including breast-conserving approaches, for appropriately selected patients. Whereas this transition occurred over several decades, until recently axillary lymph node dissection (ALND) remained standard practice for patients with both node-positive and node-negative breast cancer. The introduction of sentinel lymph node dissection (SLND) was a major departure from ALND allowing for an alternative for nodal staging with less morbidity for the increasing population of patients presenting with clinically node-negative disease.1,2 Although some early studies suggested a survival advantage for patients who undergo ALND compared with no axillary surgery, the likelihood that removing negative nodes could improve outcomes has been questioned. SLND has become the standard of care for patients with clinically node-negative disease. With fewer nodes removed, pathologists can perform a more detailed examination. This allows for improved staging and increases the detection of small-volume metastases. As the population of patients with small burden nodal disease has increased, there has been a growing debate regarding the optimal treatment of node-positive disease. The consensus statement from the American Society of Clinical Oncology and the guidelines from the National Comprehensive Cancer Network recommend a completion ALND (cALND) when metastases are identified on SLND.3,4 These recommendations are supported by data from a meta-analysis of 69 trials, which included 8,059 patients who underwent SLND and cALND, where 53% of the patients with a positive SLN were found to have additional disease in non-SLNs.5 The cALND allows for assessment of the total number of nodes involved, which has prognostic and potentially therapeutic implications. The American Joint Committee on Cancer staging system includes designations for metastases in ≥10 lymph nodes (pN3), 4–9 lymph nodes (pN2), and 1–3 lymph nodes (pN1), as well as micrometastasis (pN1mi; >0.2–2.0 mm) and isolated tumor cells (pN0(i +); ≤0.2 mm).6 The extent of nodal disease may have implications in terms of local-regional control as well as use of systemic therapy and regional and nodal irradiation.7,8 Although cALND has been standard practice when SLNs are involved with metastatic disease, many have questioned the need for cALND in patients with small-volume metastases. The meta-analysis previously discussed showed that 53% of patients had additional nodes with metastatic disease on cALND.5 When considering patients with micrometastatic disease in the SLN(s), the rate of non-SLN involvement is as low as 20%; and for patients with isolated tumor cells the rate decreases to 12%.9,10 These findings have prompted a trend toward omitting cALND in selected patients. In an analysis of the surveillance, epidemiology, and end results (SEER) data from 1998 to 2004, up to 16% of SLN-positive patients did not undergo cALND—a trend seen in older women with low-grade, estrogen receptor (ER)-positive tumors. Considering only patients with micrometastasis in the SLN, the proportion treated with SLND alone increased from 21 to 38%.11 Similarly, a review of the National Cancer Data Base (NCDB) data from 1998 to 2005 revealed that 20.8% of patients with a positive SLN did not undergo cALND. To evaluate a more contemporary cohort, these authors analyzed data from patients diagnosed between 2004 and 2005 and found that the proportion of patients who underwent SLND alone increased in patients with micrometastases, whereas the proportion of patients who underwent SLND alone after macrometastases were identified in the SLN declined slightly during the same time period. At a median follow-up of just more than five years, there were no differences in axillary recurrence rates or survival for patients who underwent SLND alone versus SLND with cALND. This was true for patients with both micrometastases and macrometastases in the SLN.12 These data suggest that many clinicians do not believe that cALND plays an important role in the management of patients with small-volume metastases in the SLN. The American College of Surgeons Oncology Group (ACOSOG) recently reported the results of the Z0011 trial—a prospective, randomized trial designed to evaluate the impact of cALND on local-regional recurrence and survival in patients with early-stage breast cancer and a positive SLN. The purpose of this article is to review the results of the Z0011 trial and to discuss how these data can be implemented in multidisciplinary practice.