Hyperactive CDK2 Activity in Basal-like Breast Cancer Imposes a Genome Integrity Liability that Can Be Exploited by Targeting DNA Polymerase ε.

Knowledge of fundamental differences between breast cancer subtypes has driven therapeutic advances; however, basal-like breast cancer (BLBC) remains clinically intractable. Because BLBC exhibits alterations in DNA repair enzymes and cell-cycle checkpoints, elucidation of factors enabling the genomic instability present in this subtype has the potential to reveal novel anti-cancer strategies. Here, we demonstrate that BLBC is especially sensitive to suppression of iron-sulfur cluster (ISC) biosynthesis and identify DNA polymerase epsilon (POLE) as an ISC-containing protein that underlies this phenotype. In BLBC cells, POLE suppression leads to replication fork stalling, DNA damage, and a senescence-like state or cell death. In contrast, luminal breast cancer and non-transformed mammary cells maintain viability upon POLE suppression but become dependent upon an ATR/CHK1/CDC25A/CDK2 DNA damage response axis. We find that CDK1/2 targets exhibit hyperphosphorylation selectively in BLBC tumors, indicating that CDK2 hyperactivity is a genome integrity vulnerability exploitable by targeting POLE.

Image-based multiplex immune profiling of cancer tissues: translational implications. A report of the International Immuno-oncology Biomarker Working Group on Breast Cancer.

Recent advances in the field of immuno-oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high-throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Effectiveness and toxicity of five-fraction prone accelerated partial breast irradiation.

PURPOSE: Our institution was an early adopter of 5-fraction accelerated partial breast irradiation (ABPI) to treat women with early-stage breast cancer. This study reports long-term oncologic and cosmetic outcomes. METHODS: We included patients receiving APBI 600 cGy × 5 fx delivered every other day or every day between 2010 and 2022. Logistic regression models were used to identify factors associated with development of late toxicities, clinician, and patient-rated cosmesis. Kaplan-Meier methodology was used to calculate overall survival (OS), disease-free survival (DFS), and locoregional recurrence-free survival (LR-RFS). RESULTS: 442 patients received APBI either daily (56%) or every other day (44%) in the prone position (92%). At a median follow-up of 48 months (range: 5.96-155 months), 12 (2.7%) patients developed a local recurrence (LR). Out of 258 patients with > 3-month toxicity data available, the most common late grade ≥ 2 adverse event was breast fibrosis (6.2%). On multivariate analysis, daily APBI treatment (vs every other day) did not correlate with an increased risk of any late grade ≥ 2 toxicity though it did correlate with a lower risk of any late grade ≥ 2 fibrosis. Overall, at a median follow-up of 80 months, the rates of good-excellent physician and patient-rated cosmesis were 95% and 85%, respectively, with no difference between patients treated on consecutive vs. every other day. On multivariate analysis, patients who did not receive any adjuvant therapy were at increased risk of developing a LR. Five-year OS, LRFS, and DFS were 97.2%, 97.7%, and 89.5%, respectively. CONCLUSIONS: Five-fraction APBI delivered primarily in the prone position either daily or every other day was effective with low rates of local recurrence, minimal toxicity, and excellent cosmesis at long-term follow-up.

Improved outcomes for triple negative breast cancer brain metastases patients after stereotactic radiosurgery and new systemic approaches.

PURPOSE: Although ongoing studies are assessing the efficacy of new systemic therapies for patients with triple negative breast cancer (TNBC), the overwhelming majority have excluded patients with brain metastases (BM). Therefore, we aim to characterize systemic therapies and outcomes in a cohort of patients with TNBC and BM managed with stereotactic radiosurgery (SRS) and delineate predictors of increased survival. METHODS: We used our prospective patient registry to evaluate data from 2012 to 2023. We included patients who received SRS for TNBC-BM. A competing risk analysis was conducted to assess local and distant control. RESULTS: Forty-three patients with 262 tumors were included. The median overall survival (OS) was 16 months (95% CI 13-19 months). Predictors of increased OS after initial SRS include Breast GPA score > 1 (p < 0.001) and use of immunotherapy such as pembrolizumab (p = 0.011). The median time on immunotherapy was 8 months (IQR 4.4, 11.2). The median time to new CNS lesions after the first SRS treatment was 17 months (95% CI 12-22). The cumulative rate for development of new CNS metastases after initial SRS at 6 months, 1 year, and 2 years was 23%, 40%, and 70%, respectively. Thirty patients (70%) underwent multiple SRS treatments, with a median time of 5 months (95% CI 0.59-9.4 months) for the appearance of new CNS metastases after second SRS treatment. CONCLUSIONS: TNBC patients with BM can achieve longer survival than might have been previously anticipated with median survival now surpassing one year. The use of immunotherapy is associated with increased median OS of 23 months.

NFS1 undergoes positive selection in lung tumours and protects cells from ferroptosis.

Environmental nutrient levels impact cancer cell metabolism, resulting in context-dependent gene essentiality. Here, using loss-of-function screening based on RNA interference, we show that environmental oxygen levels are a major driver of differential essentiality between in vitro model systems and in vivo tumours. Above the 3-8% oxygen concentration typical of most tissues, we find that cancer cells depend on high levels of the iron-sulfur cluster biosynthetic enzyme NFS1. Mammary or subcutaneous tumours grow despite suppression of NFS1, whereas metastatic or primary lung tumours do not. Consistent with a role in surviving the high oxygen environment of incipient lung tumours, NFS1 lies in a region of genomic amplification present in lung adenocarcinoma and is most highly expressed in well-differentiated adenocarcinomas. NFS1 activity is particularly important for maintaining the iron-sulfur co-factors present in multiple cell-essential proteins upon exposure to oxygen compared to other forms of oxidative damage. Furthermore, insufficient iron-sulfur cluster maintenance robustly activates the iron-starvation response and, in combination with inhibition of glutathione biosynthesis, triggers ferroptosis, a non-apoptotic form of cell death. Suppression of NFS1 cooperates with inhibition of cysteine transport to trigger ferroptosis in vitro and slow tumour growth. Therefore, lung adenocarcinomas select for expression of a pathway that confers resistance to high oxygen tension and protects cells from undergoing ferroptosis in response to oxidative damage.

Outcomes of Breast Cancer Patients Treated with Chemotherapy, Biologic Therapy, Endocrine Therapy, or Active Surveillance During the COVID-19 Pandemic.

PURPOSE: Provide real-world data regarding the risk for SARS-CoV-2 infection and mortality in breast cancer (BC) patients on active cancer treatment. METHODS: Clinical data were abstracted from the 3778 BC patients seen at a multisite cancer center in New York between February 1, 2020 and May 1, 2020, including patient demographics, tumor histology, cancer treatment, and SARS-CoV-2 testing results. Incidence of SARS-CoV-2 infection by treatment type (chemotherapy [CT] vs endocrine and/or HER2 directed therapy [E/H]) was compared by Inverse Probability of Treatment Weighting. In those diagnosed with SARS-CoV-2 infection, Mann-Whitney test was used to a assess risk factors for severe disease and mortality. RESULTS: Three thousand sixty-two patients met study inclusion criteria with 641 patients tested for SARS-COV-2 by RT-PCR or serology. Overall, 64 patients (2.1%) were diagnosed with SARS-CoV-2 infection by either serology, RT-PCR, or documented clinical diagnosis. Comparing matched patients who received chemotherapy (n = 379) with those who received non-cytotoxic therapies (n = 2343) the incidence of SARS-CoV-2 did not differ between treatment groups (weighted risk; 3.5% CT vs 2.7% E/H, P = .523). Twenty-seven patients (0.9%) expired over follow-up, with 10 deaths attributed to SARS-CoV-2 infection. Chemotherapy was not associated with increased risk for death following SARS-CoV-2 infection (weighted risk; 0.7% CT vs 0.1% E/H, P = .246). Advanced disease (stage IV), age, BMI, and Charlson's Comorbidity Index score were associated with increased mortality following SARS-CoV-2 infection (P ≤ .05). CONCLUSION: BC treatment, including chemotherapy, can be safely administered in the context of enhanced infectious precautions, and should not be withheld particularly when given for curative intent.

Atezolizumab and Nab-Paclitaxel in Advanced Triple-Negative Breast Cancer.

BACKGROUND: Unresectable locally advanced or metastatic triple-negative (hormone-receptor-negative and human epidermal growth factor receptor 2 [HER2]-negative) breast cancer is an aggressive disease with poor outcomes. Nanoparticle albumin-bound (nab)-paclitaxel may enhance the anticancer activity of atezolizumab. METHODS: In this phase 3 trial, we randomly assigned (in a 1:1 ratio) patients with untreated metastatic triple-negative breast cancer to receive atezolizumab plus nab-paclitaxel or placebo plus nab-paclitaxel; patients continued the intervention until disease progression or an unacceptable level of toxic effects occurred. Stratification factors were the receipt or nonreceipt of neoadjuvant or adjuvant taxane therapy, the presence or absence of liver metastases at baseline, and programmed death ligand 1 (PD-L1) expression at baseline (positive vs. negative). The two primary end points were progression-free survival (in the intention-to-treat population and PD-L1-positive subgroup) and overall survival (tested in the intention-to-treat population; if the finding was significant, then it would be tested in the PD-L1-positive subgroup). RESULTS: Each group included 451 patients (median follow-up, 12.9 months). In the intention-to-treat analysis, the median progression-free survival was 7.2 months with atezolizumab plus nab-paclitaxel, as compared with 5.5 months with placebo plus nab-paclitaxel (hazard ratio for progression or death, 0.80; 95% confidence interval [CI], 0.69 to 0.92; P=0.002); among patients with PD-L1-positive tumors, the median progression-free survival was 7.5 months and 5.0 months, respectively (hazard ratio, 0.62; 95% CI, 0.49 to 0.78; P<0.001). In the intention-to-treat analysis, the median overall survival was 21.3 months with atezolizumab plus nab-paclitaxel and 17.6 months with placebo plus nab-paclitaxel (hazard ratio for death, 0.84; 95% CI, 0.69 to 1.02; P=0.08); among patients with PD-L1-positive tumors, the median overall survival was 25.0 months and 15.5 months, respectively (hazard ratio, 0.62; 95% CI, 0.45 to 0.86). No new adverse effects were identified. Adverse events that led to the discontinuation of any agent occurred in 15.9% of the patients who received atezolizumab plus nab-paclitaxel and in 8.2% of those who received placebo plus nab-paclitaxel. CONCLUSIONS: Atezolizumab plus nab-paclitaxel prolonged progression-free survival among patients with metastatic triple-negative breast cancer in both the intention-to-treat population and the PD-L1-positive subgroup. Adverse events were consistent with the known safety profiles of each agent. (Funded by F. Hoffmann-La Roche/Genentech; IMpassion130 ClinicalTrials.gov number, NCT02425891 .).

Serial single-cell profiling analysis of metastatic TNBC during Nab-paclitaxel and pembrolizumab treatment.

PURPOSE: Immunotherapy has recently been shown to improve outcomes for advanced PD-L1-positive triple-negative breast cancer (TNBC) in the Impassion130 trial, leading to FDA approval of the first immune checkpoint inhibitor in combination with taxane chemotherapy. To further develop predictive biomarkers and improve therapeutic efficacy of the combination, interrogation of the tumor immune microenvironment before therapy as well as during each component of treatment is crucial. Here we use single-cell RNA sequencing (scRNA-seq) on tumor biopsies to assess immune cell changes from two patients with advanced TNBC treated in a prospective trial at predefined serial time points, before treatment, on taxane chemotherapy and on chemo-immunotherapy. METHODS: Both patients (one responder and one progressor) received the trial therapy, in cycle 1 nab-paclitaxel given as single agent, in cycle 2 nab-paclitaxel in combination with pembrolizumab. Tumor core biopsies were obtained at baseline, 3 weeks (after cycle 1, chemotherapy alone) and 6 weeks (after cycle 2, chemo-immunotherapy). Single-cell RNA sequencing (scRNA-seq) of both cancer cells and infiltrating immune cells isolated were performed from fresh tumor core biopsy specimens by 10 × chromium sequencing. RESULTS: ScRNA-seq analysis showed significant baseline heterogeneity of tumor-infiltrating immune cell populations between the two patients as well as modulation of the tumor microenvironment by chemotherapy and immunotherapy. In the responding patient there was a population of PD-1high-expressing T cells which significantly decreased after nab-paclitaxel plus pembrolizumab treatment as well as a presence of tissue-resident memory T cells (TRM). In contrast, tumors from the patient with rapid disease progression showed a prevalent and persistent myeloid compartment. CONCLUSIONS: Our study provides a deep cellular analysis of on-treatment changes during chemo-immunotherapy for advanced TNBC, demonstrating not only feasibility of single-cell analyses on serial tumor biopsies but also the heterogeneity of TNBC and differences in on-treatment changes in responder versus progressor.

Atezolizumab plus nab-paclitaxel as first-line treatment for unresectable, locally advanced or metastatic triple-negative breast cancer (IMpassion130): updated efficacy results from a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Immunotherapy in combination with chemotherapy has shown promising efficacy across many different tumour types. We report the prespecified second interim overall survival analysis of the phase 3 IMpassion130 study assessing the efficacy and safety of atezolizumab plus nab-paclitaxel in patients with unresectable, locally advanced or metastatic triple-negative breast cancer. METHODS: In this randomised, placebo-controlled, double-blind, phase 3 trial, done in 246 academic centres and community oncology practices in 41 countries, patients aged 18 years or older, with previously untreated, histologically documented, locally advanced or metastatic triple-negative breast cancer, and Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible. Patients were randomly assigned (1:1) using a permuted block method (block size of four) and an interactive voice-web response system. Randomisation was stratified by previous taxane use, liver metastases, and PD-L1 expression on tumour-infiltrating immune cells. Patients received atezolizumab 840 mg or matching placebo intravenously on day 1 and day 15 of every 28-day cycle and nab-paclitaxel 100 mg/m2 of body surface area intravenously on days 1, 8, and 15 until progression or unacceptable toxicity. Investigators, patients, and the funder were masked to treatment assignment. Coprimary endpoints were investigator-assessed progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1 and overall survival, assessed in the intention-to-treat population and in patients with PD-L1 immune cell-positive tumours (tumours with ≥1% PD-L1 expression). The final progression-free survival results were previously reported at the first interim overall survival analysis. The prespecified statistical testing hierarchy meant that overall survival in the subgroup of PD-L1 immune cell-positive patients could only be formally tested if overall survival was significantly different between the treatment groups in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02425891. FINDINGS: Between June 23, 2015, and May 24, 2017, 902 patients were enrolled, of whom 451 were randomly assigned to receive atezolizumab plus nab-paclitaxel and 451 were assigned to receive placebo plus nab-paclitaxel (the intention-to-treat population). Six patients from each group did not receive treatment. At the second interim analysis (data cutoff Jan 2, 2019), median follow-up was 18·5 months (IQR 9·6-22·8) in the atezolizumab group and 17·5 months (8·4-22·4) in the placebo group. Median overall survival in the intention-to-treat patients was 21·0 months (95% CI 19·0-22·6) with atezolizumab and 18·7 months (16·9-20·3) with placebo (stratified hazard ratio [HR] 0·86, 95% CI 0·72-1·02, p=0·078). In the exploratory overall survival analysis in patients with PD-L1 immune cell-positive tumours, median overall survival was 25·0 months (95% CI 19·6-30·7) with atezolizumab versus 18·0 months (13·6-20·1) with placebo (stratified HR 0·71, 0·54-0·94]). As of Sept 3, 2018 (the date up to which updated safety data were available), the most common grade 3-4 adverse events were neutropenia (38 [8%] of 453 patients in the atezolizumab group vs 36 [8%] of 437 patients in the placebo group), peripheral neuropathy (25 [6%] vs 12 [3%]), decreased neutrophil count (22 [5%] vs 16 [4%]), and fatigue (17 [4%] vs 15 [3%]). Treatment-related deaths occurred in two (<1%) patients in the atezolizumab group (autoimmune hepatitis related to atezolizumab [n=1] and septic shock related to nab-paclitaxel [n=1]) and one (<1%) patient in the placebo group (hepatic failure). No new treatment-related deaths have been reported since the primary clinical data cutoff date (April 17, 2018). INTERPRETATION: Consistent with the first interim analysis, this second interim overall survival analysis of IMpassion130 indicates no significant difference in overall survival between the treatment groups in the intention-to-treat population but suggests a clinically meaningful overall survival benefit with atezolizumab plus nab-paclitaxel in patients with PD-L1 immune cell-positive disease. However, this positive result could not be formally tested due to the prespecified statistical testing hierarchy. For patients with PD-L1 immune cell-positive metastatic triple-negative breast cancer, atezolizumab plus nab-paclitaxel is an important therapeutic option in a disease with high unmet need. FUNDING: F Hoffmann-La Roche and Genentech.

Update on tumor-infiltrating lymphocytes (TILs) in breast cancer, including recommendations to assess TILs in residual disease after neoadjuvant therapy and in carcinoma in situ: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer.

Morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer is gaining momentum as evidence strengthens the clinical relevance of this immunological biomarker. TILs in the post-neoadjuvant residual disease setting are acquiring increasing importance as a stratifying marker in clinical trials, considering the raising interest on immunotherapeutic strategies after neoadjuvant chemotherapy. TILs in ductal carcinoma in situ, with or without invasive carcinoma, represent an emerging area of clinical breast cancer research. The aim of this report is to update pathologists, clinicians and researchers on TIL assessment in both the post-neoadjuvant residual disease and the ductal carcinoma in situ settings. The International Immuno-Oncology Working Group proposes a method for assessing TILs in these settings, based on the previously published International Guidelines on TIL Assessment in Breast Cancer. In this regard, these recommendations represent a consensus guidance for pathologists, aimed to achieve the highest possible consistency among future studies.

Tumor-Infiltrating Lymphocytes in a Contemporary Cohort of Women with Ductal Carcinoma In Situ (DCIS).

BACKGROUND: Growing evidence suggests that the tumor immune microenvironment influences breast cancer development and prognosis. Density of tumor-infiltrating lymphocytes (TILs) within invasive breast cancer is correlated with response to therapy, especially in triple-negative disease. The clinical relevance and outcomes of TILs within ductal carcinoma in situ (DCIS) are less understood. METHODS: Our institutional database of 668 patients with pure DCIS from 2010 to 2018 was queried. TILs were evaluated by International TILs Working Group guidelines. Percentage of TILs was assessed from the densest focus (hotspot) in one high-power field of stroma touching the basement membrane. Statistical methods included cluster analyses (to define sparse versus dense TILs), logistic, and Cox regression models. RESULTS: Sixty-nine patients with DCIS and TILs were evaluated, of whom 54 (78%) were treated by breast-conserving surgery. Thirteen (19%) patients had ipsilateral recurrence. Each recurrence (n = 13) was matched to four controls (n = 56) based on date of surgery. Median follow-up was 6.7 years. TILs were defined as sparse (< 45%) or dense (≥ 45%). Dense TILs were associated with younger age (p = 0.045), larger tumor size (p < 0.001), high nuclear grade (p = 0.010), comedo histology (p = 0.033), necrosis (p = 0.027), estrogen receptor (ER) negativity (p = 0.037), and ipsilateral recurrence (p = 0.001). Nine patients with dense TILs had mean time to recurrence of 73.5 months compared with four patients with sparse TILs with mean time to recurrence of 97.9 months (p = 0.003). CONCLUSIONS: Dense TILs were significantly associated with age, tumor size, nuclear grade, comedo histology, necrosis, and ER status and was a significant predictor of recurrence in patients with pure DCIS.

Checkpoint inhibitors in triple-negative breast cancer (TNBC): Where to go from here.

Advances in cancer immunotherapy and a growing body of research have focused on the role of the antitumor response in breast cancer. Triple-negative breast cancer (TNBC) is the most immunogenic breast cancer subtype, and there is strong evidence that tumor-infiltrating lymphocytes in TNBC have prognostic value and are associated with clinical outcome and improved survival. Evading antitumor immunity is a hallmark for the development and progression of cancer. Immunotherapy studies have focused on the role of the programmed cell death-1 (PD-1) receptor/programmed death-ligand 1 (PD-L1) pathway in maintaining immunosuppression in the tumor microenvironment. Blockade of the PD-1/PD-L1 axis has emerged as a promising therapeutic option to enhance antitumor immunity and is actively being investigated in TNBC, with encouraging results. In this article, the authors review the current literature on checkpoint inhibitors in TNBC with a focus on PD-1/PD-L1 antibodies and discuss combination strategies and novel approaches for improving antitumor immunity and clinical outcome. Cancer 2018;124:2086-103. © 2018 American Cancer Society.

Serial immunological parameters in a phase II trial of exemestane and low-dose oral cyclophosphamide in advanced hormone receptor-positive breast cancer.

BACKGROUND AND PURPOSE: Resistance to endocrine therapies in hormone receptor (HR)-positive breast cancer is a significant challenge. Prior studies have shown that low-dose oral cyclophosphamide can transiently deplete regulatory T cells (Tregs) and improve anti-tumor immunity. We investigated the combination of exemestane with cyclophosphamide in patients with advanced HR-positive breast cancer and assessed changes in circulating immune cell subsets. METHODS: This was a single-arm phase II trial of exemestane with cyclophosphamide in patients with metastatic HR-positive/HER2-negative breast cancer who had progressed on prior endocrine therapy (ClinicalTrials.gov: NCT01963481). Primary endpoint was progression-free survival (PFS) at 3 months (RECIST 1.1). Secondary objectives included median PFS, objective response rate, duration of response, and safety. Circulating Tregs (FOXP3+Helios+) and other immune cell subsets were monitored during treatment and compared with healthy controls. RESULTS: Twenty-three patients were enrolled. Treatment was well tolerated, without grade 4/5 toxicities. Objective responses were seen in 6/23 patients (26.1%; 95% CI 10.2-48.4%) and were durable (median 11.6 months). Three-month PFS rate was 50.1% (95% CI 33.0-76.0%); median PFS was 4.23 months (95% CI 2.8-11.7). No treatment-related decrease in Tregs was observed. However, elevated baseline levels of Naïve Tregs [greater than 2.5 (the median of the naïve Tregs)] were associated with relative risk of disease progression or death [hazard ratio 11.46 (95% CI 2.32-56.5)]. In addition, the baseline levels of Naïve Tregs (adj-p = 0.04), Memory Tregs (adj-p = 0.003), CD4 + Central Memory T cells (adj-p = 0.0004), PD-1 + CD4 + Central Memory T cells (adj-p = 0.008), and PD-1 + CD4 + Effector Memory T cells (adj-p = 0.009) were significantly greater in the patients than in the healthy controls; the baseline levels of  %CD4 + Naïve T cells (adj-p = 0.0004) were significantly lower in patients compared with healthy controls (n = 40). CONCLUSION: Treg depletion was not observed with low-dose cyclophosphamide when assessed by the specific marker FOXP3 + Helios +; however, baseline naïve Tregs were associated with 3-month PFS. Exemestane/cyclophosphamide combination had favorable safety profile with evidence of clinical activity in heavily pretreated patients.

Post-mastectomy Radiation Therapy in Breast Cancer Patients with Nodal Micrometastases.

BACKGROUND: Recent data support the use of post-mastectomy radiation therapy (PMRT) in women with one to three positive lymph nodes; however, the benefit of PMRT in patients with micrometastatic nodal disease (N1mi) is unknown. We evaluated the survival impact of PMRT in patients with N1mi within the National Cancer Database. METHODS: The pattern of care and survival benefit of PMRT was examined in women with pT1-2N1mi breast cancer who underwent mastectomy without neoadjuvant chemotherapy. Univariable and multivariable Cox proportional hazard models were employed for survival analysis, and subanalyses of high-risk patients and a propensity score-matched (PSM) cohort were completed. RESULTS: From 2004 to 2014, we identified 14,019 patients who fitted the study criteria. PMRT was delivered in 18.5% of patients and its use increased over the study period. Patients treated with PMRT were younger, had better performance status and larger primaries, were estrogen receptor (ER)-negative, had higher grade, lymphovascular invasion and positive surgical margins, and more often received systemic therapy. PMRT was significantly associated with overall survival (OS) in univariable analysis (hazard ratio [HR] 0.75 [0.64-0.89]), but was not significant in multivariable analysis (adjusted HR 1.01 [0.84-1.20]). There was no survival benefit to PMRT in ER-negative, high-grade, and/or young patients. There were 2 (0.9%) death events in the sentinel lymph node biopsy (SLNB) + PMRT group versus 21 (2.9%) in the SLNB-alone group (log-rank p = 0.053), and 8 (3.9%) death events in the axillary lymph node biopsy (ALNB) + PMRT group versus 27 (3.6%) in the axillary lymph node dissection-alone group (p = 0.82). There was no significant association between PMRT and OS within the PSM subgroup. CONCLUSION: In this largest reported retrospective study, no OS differences were associated with PMRT, which suggests that PMRT may not benefit every patient with microscopic nodal disease.

Antibody-drug conjugates in triple negative breast cancer.

Triple negative breast cancer (TNBC) is a heterogeneous disease that comprises 15-20% of all breast cancers and is more frequently seen in younger women, African-Americans, and BRCA1 expression. Advanced TNBC carries aggressive features and is associated with overall poor outcomes. Unfortunately, there are no targeted therapies available for non-BRCA associated TNBC, which remains a high unmet therapeutic need. One emerging treatment modality includes antibody-drug conjugates which are highly selective monoclonal antibodies conjugated to cytotoxic agents, designed to deliver cytotoxic drugs to antigen-expressing tumor cells. This review will highlight three antibody-drug conjugates currently being evaluated in TNBC (CDX-011, SGN-LIV1a, IMMU-132), including one that has been given Breakthrough Therapy designation from the US FDA.

A phase I trial of ganetespib in combination with paclitaxel and trastuzumab in patients with human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer.

BACKGROUND: Targeted therapies in HER2-positive metastatic breast cancer significantly improve outcomes but efficacy is limited by therapeutic resistance. HER2 is an acutely sensitive Heat Shock Protein 90 (HSP90) client and HSP90 inhibition can overcome trastuzumab resistance. Preclinical data suggest that HSP90 inhibition is synergistic with taxanes with the potential for significant clinical activity. We therefore tested ganetespib, a HSP90 inhibitor, in combination with paclitaxel and trastuzumab in patients with trastuzumab-refractory HER2-positive metastatic breast cancer. METHODS: In this phase I dose-escalation study, patients with trastuzumab-resistant HER2-positive metastatic breast cancer received weekly trastuzumab (2 mg/kg) and paclitaxel (80 mg/m2) on days 1, 8, 15, and 22 of a 28-day cycle with escalating doses of ganetespib (100 mg/m2, 150 mg/m2, and a third cohort of 125 mg/m2 if needed) on days 1, 8, and 15. Therapy was continued until disease progression or toxicity. The primary objective was to establish the safety and maximum tolerated dose and/or recommended phase II dose (RP2D) of this therapy. The secondary objectives included evaluation of the effects of ganetespib on the pharmacokinetics of paclitaxel, and to make a preliminary assessment of the efficacy of the combination therapy. RESULTS: Dose escalation was completed for the two main cohorts without any observed dose-limiting toxicities. Nine patients received treatment. The median prior lines of anti-HER2 therapy numbered three (range 2-4), including prior pertuzumab in 9/9 patients and ado-trastuzumab emtansine (T-DM1) in 8/9 patients. The most common grade 1/2 adverse events (AEs) were diarrhea, fatigue, anemia, and rash. There were no grade 4 AEs related to ganetespib. The overall response rate was 22% (2/9 patients had partial response) and stable disease was seen in 56% (5/9 patients). The clinical benefit rate was 44% (4/9 patients). The median progression-free survival was 20 weeks (range 8-55). CONCLUSION: The RP2D of ganetespib is 150 mg/m2 in combination with weekly paclitaxel plus trastuzumab. The combination was safe and well tolerated. Despite prior taxanes, pertuzumab, and T-DM1, clinical activity of this triplet regimen in this heavily pretreated cohort is promising and warrants further study in HER2-positive metastatic breast cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT02060253 . Registered 30 January 2014.

Voxelwise analysis of simultaneously acquired and spatially correlated 18 F-fluorodeoxyglucose (FDG)-PET and intravoxel incoherent motion metrics in breast cancer.

PURPOSE: Diffusion-weighted imaging (DWI) and 18 F-fluorodeoxyglucose-positron emission tomography (18 F-FDG-PET) independently correlate with malignancy in breast cancer, but the relationship between their structural and metabolic metrics is not completely understood. This study spatially correlates diffusion, perfusion, and glucose avidity in breast cancer with simultaneous PET/MR imaging and compares correlations with clinical prognostics. METHODS: In this Health Insurance Portability and Accountability Act-compliant prospective study, with written informed consent and approval of the institutional review board and using simultaneously acquired FDG-PET and DWI, tissue diffusion (Dt ), and perfusion fraction (fp ) from intravoxel incoherent motion (IVIM) analysis were registered to FDG-PET within 14 locally advanced breast cancers. Lesions were analyzed using 2D histograms and correlation coefficients between Dt , fp , and standardized uptake value (SUV). Correlations were compared with prognostics from biopsy, metastatic burden from whole-body PET, and treatment history. RESULTS: SUV||Dt correlation coefficient significantly distinguished treated (0.11 ± 0.24) from nontreated (-0.33 ± 0.26) patients (P = 0.005). SUV||fp correlations were on average negative for the whole cohort (-0.17 ± 0.13). CONCLUSION: Simultaneously acquired and registered FDG-PET/DWI allowed quantifiable descriptions of breast cancer microenvironments that may provide a framework for monitoring and predicting response to treatment. Magn Reson Med 78:1147-1156, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Nab-paclitaxel-induced cystoid macular edema in a patient with pre-existing optic neuropathy.

Paclitaxel is a widely used chemotherapy agent that has rarely been associated with ophthalmic toxicities. Cystoid macular edema is one such rare side effect of paclitaxel therapy. Its pathophysiology remains poorly understood. Here, we report on a 69-year-old woman who developed cystoid macular edema associated with the albumin-bound formulation of paclitaxel after several months of therapy for breast cancer. After 2 months of drug withdrawal, her vision improved and there was a significant improvement in the macular edema by imaging with spectral-domain optical coherence tomography. Oncologists using taxane agents should be aware of this rare adverse outcome for timely patient referral to an ophthalmologist and appropriate treatment to preserve a patient's visual acuity.

Local radiotherapy and granulocyte-macrophage colony-stimulating factor to generate abscopal responses in patients with metastatic solid tumours: a proof-of-principle trial.

BACKGROUND: An abscopal response describes radiotherapy-induced immune-mediated tumour regression at sites distant to the irradiated field. Granulocyte-macrophage colony-stimulating factor is a potent stimulator of dendritic cell maturation. We postulated that the exploitation of the pro-immunogenic effects of radiotherapy with granulocyte-macrophage colony-stimulating factor might result in abscopal responses among patients with metastatic cancer. METHODS: Patients with stable or progressing metastatic solid tumours, on single-agent chemotherapy or hormonal therapy, with at least three distinct measurable sites of disease, were treated with concurrent radiotherapy (35 Gy in ten fractions, over 2 weeks) to one metastatic site and granulocyte-macrophage colony-stimulating factor (125 µg/m(2) subcutaneously injected daily for 2 weeks, starting during the second week of radiotherapy). This course was repeated, targeting a second metastatic site. A Simon's optimal two-stage design was chosen for this trial: an additional 19 patients could be enrolled in stage 2 only if at least one patient among the first ten had an abscopal response. If no abscopal responses were seen among the first ten patients, the study would be deemed futile and terminated. The primary endpoint was the proportion of patients with an abscopal response (defined as at least a 30% decrease in the longest diameter of the best responding abscopal lesion). Secondary endpoints were safety and survival. Analyses were done based on intention to treat. The trial has concluded accrual, and is registered with ClinicalTrials.gov, number NCT02474186. FINDINGS: From April 7, 2003, to April 3, 2012, 41 patients with metastatic cancer were enrolled. In stage 1 of the Simon's two-stage design, ten patients were enrolled: four of the first ten patients had abscopal responses. Thus, the trial proceeded to stage 2, as planned, and an additional 19 patients were enrolled. Due to protocol amendments 12 further patients were enrolled. Abscopal responses occurred in eight (27·6%, 95% CI 12·7-47·2) of the first 29 patients, and 11 (26·8%, 95% CI 14·2-42·9) of 41 accrued patients (specifically in four patients with non-small-cell lung cancer, five with breast cancer, and two with thymic cancer). The most common grade 3-4 adverse events were fatigue (six patients) and haematological (ten patients). Additionally, a serious adverse event of grade 4 pulmonary embolism occurred in one patient. INTERPRETATION: The combination of radiotherapy with granulocyte-macrophage colony-stimulating factor produced objective abscopal responses in some patients with metastatic solid tumours. This finding represents a promising approach to establish an in-situ anti-tumour vaccine. Further research is warranted in this area. FUNDING: New York University School of Medicine's Department of Radiation Oncology and Cancer Institute.