Catherine Van Poznak

Bisphosphonate-Associated Osteonecrosis of the Jaw: Report of a Task Force of the American Society for Bone and Mineral Research

ONJ has been increasingly suspected to be a potential complication of bisphosphonate therapy in recent years. Thus, the ASBMR leadership appointed a multidisciplinary task force to address key questions related to case definition, epidemiology, risk factors, diagnostic imaging, clinical management, and future areas for research related to the disorder. This report summarizes the findings and recommendations of the task force.

Activating ESR1 mutations in hormone-resistant metastatic breast cancer

Breast cancer is the most prevalent cancer in women, and over two-thirds of cases express estrogen receptor-α (ER-α, encoded by ESR1). Through a prospective clinical sequencing program for advanced cancers, we enrolled 11 patients with ER-positive metastatic breast cancer. Whole-exome and transcriptome analysis showed that six cases harbored mutations of ESR1 affecting its ligand-binding domain (LBD), all of whom had been treated with anti-estrogens and estrogen deprivation therapies. A survey of The Cancer Genome Atlas (TCGA) identified four endometrial cancers with similar mutations of ESR1. The five new LBD-localized ESR1 mutations identified here (encoding p.Leu536Gln, p.Tyr537Ser, p.Tyr537Cys, p.Tyr537Asn and p.Asp538Gly) were shown to result in constitutive activity and continued responsiveness to anti-estrogen therapies in vitro. Taken together, these studies suggest that activating mutations in ESR1 are a key mechanism in acquired endocrine resistance in breast cancer therapy.

Use of Biomarkers to Guide Decisions on Adjuvant Systemic Therapy for Women With Early-Stage Invasive Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline

PURPOSE To provide recommendations on appropriate use of breast tumor biomarker assay results to guide decisions on adjuvant systemic therapy for women with early-stage invasive breast cancer. METHODS A literature search and prospectively defined study selection sought systematic reviews, meta-analyses, randomized controlled trials, prospective-retrospective studies, and prospective comparative observational studies published from 2006 through 2014. Outcomes of interest included overall survival and disease-free or recurrence-free survival. Expert panel members used informal consensus to develop evidence-based guideline recommendations. RESULTS The literature search identified 50 relevant studies. One randomized clinical trial and 18 prospective-retrospective studies were found to have evaluated the clinical utility, as defined by the guideline, of specific biomarkers for guiding decisions on the need for adjuvant systemic therapy. No studies that met guideline criteria for clinical utility were found to guide choice of specific treatments or regimens. RECOMMENDATIONS In addition to estrogen and progesterone receptors and human epidermal growth factor receptor 2, the panel found sufficient evidence of clinical utility for the biomarker assays Oncotype DX, EndoPredict, PAM50, Breast Cancer Index, and urokinase plasminogen activator and plasminogen activator inhibitor type 1 in specific subgroups of breast cancer. No biomarker except for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 was found to guide choices of specific treatment regimens. Treatment decisions should also consider disease stage, comorbidities, and patient preferences.

American Society of Clinical Oncology Executive Summary of the Clinical Practice Guideline Update on the Role of Bone-Modifying Agents in Metastatic Breast Cancer

PURPOSE To update the recommendations on the role of bone-modifying agents in the prevention and treatment of skeletal-related events (SREs) for patients with metastatic breast cancer with bone metastases. METHODS A literature search using MEDLINE and the Cochrane Collaboration Library identified relevant studies published between January 2003 and November 2010. The primary outcomes of interest were SREs and time to SRE. Secondary outcomes included adverse events and pain. An Update Committee reviewed the literature and re-evaluated previous recommendations. RESULTS Recommendations were modified to include a new agent. A recommendation regarding osteonecrosis of the jaw was added. RECOMMENDATIONS Bone-modifying agent therapy is only recommended for patients with breast cancer with evidence of bone metastases; denosumab 120 mg subcutaneously every 4 weeks, intravenous pamidronate 90 mg over no less than 2 hours, or zoledronic acid 4 mg over no less than 15 minutes every 3 to 4 weeks is recommended. There is insufficient evidence to demonstrate greater efficacy of one bone-modifying agent over another. In patients with a calculated serum creatinine clearance of more than 60 mg/min, no change in dosage, infusion time, or interval of bisphosphonate administration is required. Serum creatinine should be monitored before each dose. All patients should receive a dental examination and appropriate preventive dentistry before bone-modifying agent therapy and maintain optimal oral health. Current standards of care for cancer bone pain management should be applied at the onset of pain, in concert with the initiation of bone-modifying agent therapy. The use of biochemical markers to monitor bone-modifying agent use is not recommended.

ADAMTS1 and MMP1 proteolytically engage EGF-like ligands in an osteolytic signaling cascade for bone metastasis

Bone metastasis is mediated by complex interactions between tumor cells and resident stromal cells in the bone microenvironment. The functions of metalloproteinases in organ-specific metastasis remain poorly defined despite their well-appreciated role in matrix degradation and tumor invasion. Here, we show a mechanism whereby two distinct metalloproteinases, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS1) and matrix metalloproteinase-1 (MMP1), orchestrate a paracrine signaling cascade to modulate the bone microenvironment in favor of osteoclastogenesis and bone metastasis. Proteolytic release of membrane-bound epidermal growth factor (EGF)-like growth factors, including Amphiregulin (AREG), heparin-binding EGF (HB-EGF), and transforming growth factor alpha (TGFalpha) from tumor cells suppress the expression of osteoprotegerin (OPG) in osteoblasts and subsequently potentiate osteoclast differentiation. EGF receptor (EGFR) inhibitors block osteolytic bone metastasis by targeting EGFR signaling in bone stromal cells. Furthermore, elevated MMP1 and ADAMTS1 expression is associated with increased risk of bone metastasis in breast cancer patients. This study established MMP1 and ADAMTS1 in tumor cells, as well as EGFR signaling in osteoblasts, as promising therapeutic targets for inhibiting bone metastasis of breast cancer.

Cognitive function of older patients receiving adjuvant chemotherapy for breast cancer: A pilot prospective longitudinal study

OBJECTIVES: To report on the longitudinal cognitive functioning of older women receiving adjuvant chemotherapy for breast cancer.

Prevention of Aromatase Inhibitor-Induced Bone Loss Using Risedronate: The SABRE Trial

PURPOSE To investigate the management of bone health in women with early breast cancer (EBC) who were scheduled to receive anastrozole. PATIENTS AND METHODS Postmenopausal women with hormone receptor-positive EBC were assigned to one of three strata by risk of fragility fracture. Patients with the highest risk (H) received anastrozole 1 mg/d plus risedronate 35 mg/wk orally. Patients with moderate-risk (M) were randomly assigned in a double-blind manner to anastrozole and risedronate (A + R) or to anastrozole and placebo (A + P). Patients with lower-risk (L) received anastrozole (A) alone. Calcium and vitamin D were recommended for all patients. Lumbar spine and total hip bone mineral density (BMD) were assessed at baseline, 12 months, and 24 months. Results At 24 months, in the M group, treatment with A + R resulted in a significant increase in lumbar spine and total hip BMD compared with A + P treatment (2.2% v -1.8%; treatment ratio, 1.04; P < .0001; and 1.8% v -1.1%; treatment ratio, 1.03; P < .0001, respectively). In the H stratum, lumbar spine and total hip BMD increased significantly (3.0%; P = .0006; and 2.0%; P = .0104, respectively). Patients in the L stratum showed a significant decrease in lumbar spine BMD (-2.1%; P = .0109) and a numerical decrease in total hip BMD (-0.4%; P = .5988). Safety profiles for anastrozole and risedronate were similar to those already established. CONCLUSION In postmenopausal women at risk of fragility fracture who were receiving adjuvant anastrozole for EBC, the addition of risedronate at doses established for preventing and treating osteoporosis resulted in favorable effects in BMD during 24 months.

Oral gossypol in the treatment of patients with refractory metastatic breast cancer: a phase I/II clinical trial

Gossypol has demonstrated in vitro effects on cell cycle regulation and anti-tumor activity against mammary carcinoma cell lines. This Phase I/II study assesses both the effect of gossypol on cell cycle regulatory proteins in vivo and the clinical effect. Twenty women with refractory metastatic breast cancer received oral gossypol at daily doses between 30 and 50mg per day. Gossypol plasma levels were measured (n=8) and the modulation of the retinoblastoma (Rb) gene protein and Cyclin D1 was assessed by serial biopsies (n=4). Grade I–II toxicities with gossypol treatment included nausea in 30% of patients, fatigue 15%, emesis 15%, altered taste sensation 15% and diarrhea in 10% of patients. Two of the three patients receiving 50mg/day experienced dose limiting dermatologic toxicity (grade III). One patient had a minor response and two patients had stable disease with >50 decline in serial assessments of the serum tumor markers. Immunohistochemical analysis of cyclin D1 and Rb expression in serial biopsies of four patients revealed both a concurrent decrease in cyclin D1 expression and an increase in nuclear Rb expression in three patients. The maximal tolerated dose (MTD) of gossypol was 40mg/day. Gossypol appears to affect the expression of Rb protein and cyclin D1 in breast cancer metastases at doses achievable, yet had negligible antitumor activity against anthracycline and taxane refractory metastatic breast cancer. The cell cycle regulatory effects of gossypol suggest a potential role for gossypol as a modulating agent in conjunction with other cell cycle specific compounds.

Osteonecrosis of the maxilla and mandible in patients with advanced cancer treated with bisphosphonate therapy

Cases of osteonecrosis of the jaw (ONJ) have been reported with an increasing frequency over the past 5 years. ONJ is most often identified in patients with cancer who are receiving intravenous bisphosphonate (IVBP) therapy, but it has also been diagnosed in patients receiving oral bisphosphonates for nonmalignant conditions. To further categorize risk factors associated with ONJ and potential clinical outcomes of this condition, we performed a retrospective study of patients with metastatic bone disease treated with intravenous bisphosphonates who have been evaluated by the Memorial Sloan-Kettering Cancer Center Dental Service between January 1, 1996 and January 31, 2006. We identified 310 patients who met these criteria. Twenty-eight patients were identified as having ONJ at presentation to the Dental Service and an additional 7 patients were subsequently diagnosed with ONJ. Statistically significant factors associated with increased likelihood of ONJ included type of cancer, duration of bisphosphonate therapy, sequential IVBP treatment with pamidronate followed by zoledronic acid, comorbid osteoarthritis or rheumatoid arthritis, and benign hematologic conditions. Our data do not support corticosteroid use or oral health as a predictor of risk for ONJ. Clinical outcomes of patients with ONJ were variable with 11 patients demonstrating improvement or healing with conservative management. Our ONJ experience is presented here.

Assessment of Molecular Markers of Clinical Sensitivity to Single-Agent Taxane Therapy for Metastatic Breast Cancer

PURPOSE The taxanes affect tubulin polymerization and interfere with mitotic transition. A checkpoint blockade at the G(1)-S boundary would be expected to promote taxane-induced apoptotic cell death through a mechanism that may involve p27. Other proposed determinants of clinical taxane sensitivity/resistance include p53, members of the epidermal growth factor receptor (EGFR) superfamily (e.g., HER2, EGFR), and estrogen receptors and progesterone receptors. These molecular markers and their correlation with clinical taxane sensitivity are investigated in this retrospective clinicopathologic study. PATIENTS AND METHODS We performed immunohistochemistry (IHC) for estrogen receptors, progesterone receptors, HER2, EGFR, p53, and p27 on 144 breast tumor specimens from patients treated for metastatic breast cancer on a series of clinical trials of single-agent taxane chemotherapy for correlation with clinical response (complete or partial response). Patient characteristics that could influence response (i.e., performance status, extent of disease, and prior therapy) were also examined. RESULTS In univariate analysis, Karnofsky performance status > or = 90% and no prior history of anthracycline therapy correlated with a good clinical response to single-agent taxane (P =.003 and P =.041, respectively). None of the IHC variables tested were predictive of clinical response to taxane therapy, although p27 negativity showed a trend toward significance (P =.075). Concordance between the polyclonal antibody with HercepTest (DAKO, Carpinteria, CA) and the monoclonal antibody CB-11 (BioGenex, San Ramon, CA) was noted (kappa = 0.943); however, neither univariate nor multivariate analysis demonstrated an association between HER2 status and response to taxane chemotherapy. CONCLUSION The IHC biomarkers studied were not predictive of response to single-agent taxane chemotherapy in patients with metastatic breast cancer. Identification of molecular correlates of taxane response remains an important goal.