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Dive into the research topics where Dror Limon is active.

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Featured researches published by Dror Limon.


Neuro-oncology | 2015

Delayed contrast extravasation MRI: a new paradigm in neuro-oncology

Leor Zach; David Guez; Dianne Daniels; Yuval Grober; Ouzi Nissim; Chen Hoffmann; Dvora Nass; Alisa Talianski; Roberto Spiegelmann; Galia Tsarfaty; Sharona Salomon; Moshe Hadani; Andrew A. Kanner; Deborah T. Blumenthal; Felix Bukstein; Michal Yalon; Jacob Zauberman; Jonathan Roth; Yigal Shoshan; Evgeniya Fridman; Marc Wygoda; Dror Limon; Tzahala Tzuk; Zvi R. Cohen; Yael Mardor

BACKGROUND Conventional magnetic resonance imaging (MRI) is unable to differentiate tumor/nontumor enhancing tissues. We have applied delayed-contrast MRI for calculating high resolution treatment response assessment maps (TRAMs) clearly differentiating tumor/nontumor tissues in brain tumor patients. METHODS One hundred and fifty patients with primary/metastatic tumors were recruited and scanned by delayed-contrast MRI and perfusion MRI. Of those, 47 patients underwent resection during their participation in the study. Region of interest/threshold analysis was performed on the TRAMs and on relative cerebral blood volume maps, and correlation with histology was studied. Relative cerebral blood volume was also assessed by the study neuroradiologist. RESULTS Histological validation confirmed that regions of contrast agent clearance in the TRAMs >1 h post contrast injection represent active tumor, while regions of contrast accumulation represent nontumor tissues with 100% sensitivity and 92% positive predictive value to active tumor. Significant correlation was found between tumor burden in the TRAMs and histology in a subgroup of lesions resected en bloc (r(2) = 0.90, P < .0001). Relative cerebral blood volume yielded sensitivity/positive predictive values of 51%/96% and there was no correlation with tumor burden. The feasibility of applying the TRAMs for differentiating progression from treatment effects, depicting tumor within hemorrhages, and detecting residual tumor postsurgery is demonstrated. CONCLUSIONS The TRAMs present a novel model-independent approach providing efficient separation between tumor/nontumor tissues by adding a short MRI scan >1 h post contrast injection. The methodology uses robust acquisition sequences, providing high resolution and easy to interpret maps with minimal sensitivity to susceptibility artifacts. The presented results provide histological validation of the TRAMs and demonstrate their potential contribution to the management of brain tumor patients.


Journal of Neuro-oncology | 2016

Clinical utility and treatment outcome of comprehensive genomic profiling in high grade glioma patients.

Deborah T. Blumenthal; Addie Dvir; Tzahala Tzuk-Shina; Tzach Lior; Dror Limon; Shlomit Yust-Katz; Alejandro Lokiec; Zvi Ram; Jeffrey S. Ross; Siraj M. Ali; Roi Yair; Lior Soussan-Gutman; Felix Bokstein

Genomic research of high grade glioma (HGG) has revealed complex biology with potential for therapeutic impact. However, the utilization of this information and impact upon patient outcome has yet to be assessed. We performed capture-based next generation sequencing (NGS) genomic analysis assay of 236/315 cancer-associated genes, with average depth of over 1000 fold, to guide treatment in HGG patients. We reviewed clinical utility and response rates in correlation to NGS results. Forty-three patients were profiled: 34 glioblastomas, 8 anaplastic astrocytomas, and one patient with anaplastic oligodendroglioma. Twenty-five patients were profiled with the 315 gene panel. The median number of identified genomic alterations (GAs) per patient was 4.5 (range 1–23). In 41 patients (95 %) at least one therapeutically-actionable GA was detected, most commonly in EGFR [17 (40 %)]. Genotype-directed treatments were prescribed in 13 patients, representing a 30 % treatment decision impact. Treatment with targeted agents included everolimus as a single agent and in combination with erlotinib; erlotinib; afatinib; palbociclib; trametinib and BGJ398. Treatments targeted various genomic findings including EGFR alterations, mTOR activation, cell cycle targets and FGFR1 mutations. None of the patients showed response to respective biologic treatments. In this group of patients with HGG, NGS revealed a high frequency of GAs that lead to targeted treatment in 30 % of the patients. The lack of response suggests that further study of mechanisms of resistance in HGG is warranted before routine use of biologically-targeted agents based on NGS results.


Journal of Clinical Neuroscience | 2016

Durable brain response with pulse-dose crizotinib and ceritinib in ALK-positive non-small cell lung cancer compared with brain radiotherapy

Elizabeth Dudnik; Tali Siegal; Leor Zach; Aaron M. Allen; Dov Flex; Shlomit Yust-Katz; Dror Limon; Fred R. Hirsch; Nir Peled

Crizotinib achieves excellent systemic control in anaplastic lymphoma kinase-rearranged (ALK+) non-small cell lung cancer (NSCLC); however, central nervous system (CNS) metastases frequently occur as an early event. Whole brain irradiation, the standard treatment, results in neurocognitive impairment. We present a case series of three ALK+ NSCLC patients with progressing CNS metastases who were treated with pulse-dose crizotinib followed by ceritinib. Three ALK+ NSCLC patients treated between 2011 and 2014 (two males, two never smokers, age range 20-54years, all echinoderm microtubule-associated protein-like 4/ALK rearrangement), were diagnosed with progressing cerebral disease while receiving crizotinib. Clinico-pathological characteristics, treatments, and outcomes were analyzed. In two patients the progression was limited to the CNS, and radiological evidence of leptomeningeal spread was present in one patient. Sequential use of crizotinib 500mg administered once daily (pulse-dose) followed by ceritinib on progression achieved control of the disease in the CNS for over 18 months and over 7 months in Patient 1 and Patient 2, respectively. This strategy provided durable CNS control after whole-brain radiotherapy failure in Patient 1, and allowed the whole-brain radiotherapy to be deferred in Patient 2. Limited CNS progression was documented in Patient 3 while he was on standard-dose/pulse-dose crizotinib for 15months; durable (over 7 months) complete remission was achieved with stereotactic radiotherapy and ceritinib. Manipulating the crizotinib schedule in ALK+ NSCLC patients with CNS metastases and using a novel ALK-inhibitor at the time of further progression may provide durable CNS control and allow brain radiotherapy to be deferred.


BioMed Research International | 2015

Metastatic Salivary Gland Tumors: A Single-Center Study Demonstrating the Feasibility and Potential Clinical Benefit of Molecular-Profiling-Guided Therapy

Aron Popovtzer; Michal Sarfaty; Dror Limon; Gideon Marshack; Eli Perlow; Addie Dvir; Lior Soussan-Gutman; Salomon M. Stemmer

We evaluated the use of molecular profiling (MP) for metastatic salivary gland adenoid cystic carcinoma (SACC), for which there is no standard treatment. MP (Caris Molecular Intelligence) was performed on biopsy samples from all metastatic SACC patients attending a tertiary medical center between 2010 and 2013 (n = 14). Treatment was selected according to the biomarkers identified. Findings were compared with all similarly diagnosed patients treated in the same center between 1996 and 2009 (n = 9). For each patient, MP identified 1–13 biomarkers associated with clinical benefit for specific therapies (most commonly low/negative TS, low ERCC1). Eleven patients (79%) received MP-guided treatment (2 died prior to treatment initiation, 1 opted not to be treated), with complete response in 1, partial response (PR) in 3, and stable disease in 4. In the historical controls, 2 patients (22%) were treated (1 had PR). Median (range) progression-free survival in the first line after MP was 8.2 months (1.4–49.5+). Median (range) overall survival from diagnosis of metastatic disease was 31.3 (1.4–71.1+) versus 14.0 (1.5–116) months in the historical controls. In conclusion, MP expands treatment options and may improve clinical outcomes for metastatic SACC. In orphan diseases where randomized trials cannot be performed, MP could become a standard clinical tool.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2017

Radiotherapy in early-stage tongue squamous cell carcinoma with minor adverse features.

Orna Katz; Yuval Nachalon; Ohad Hilly; Thomas Shpitzer; Gideon Bachar; Dror Limon; Aron Popovtzer

Treatment for early‐stage tongue squamous cell carcinoma (SCC) is usually surgery alone. There is ambiguity regarding the impact of minor adverse features (MAFs) on outcome and the role of postoperative radiotherapy (PORT) in tongue SCC.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2017

Phase II organ‐preservation trial: Concurrent cisplatin and radiotherapy for advanced laryngeal cancer after response to docetaxel, cisplatin, and 5‐fluorouracil–based induction chemotherapy

Aron Popovtzer; Hanna Burnstein; Salomon M. Stemmer; Dror Limon; Ohad Hili; Gideon Bachar; Vladamir Sopov; Raphael Feinmesser; David Groshar; Jacob Shvero

The optimal treatment for locally advanced laryngeal cancer remains controversial. The purpose of this trial was to determine if the response to induction chemotherapy could select patients for organ preservation protocols, and improve larynx‐preservation rates without compromising overall survival (OS).


Cancer Journal | 2017

Role of Induction Chemotherapy Prior to Chemoradiation in Head and Neck Squamous Cell Cancer—systematic Review and Meta-analysis

Liat Vidal; Irit Ben Aharon; Dror Limon; Ezra E.W. Cohen; Aron Popovtzer

Abstract The objective of this study was to review and assess the impact of additional induction chemotherapy to concomitant chemoradiation in head and neck squamous cell cancer. We performed a comparative systematic review and meta-analysis of clinical trials of induction chemotherapy + chemoradiation and chemoradiation alone in this setting. We identified trials randomizing 1314 patients (published 2004–2015). A non–statistically significant trend was observed in favor of induction chemotherapy + chemoradiation on overall survival (hazard ratio, 0.88; 95% confidence interval, 0.75–1.04). Disease control was superior in the induction chemotherapy + chemoradiation group (hazard ratio, 0.69; 95% confidence interval, 0.57–0.83). The rate of complete response improved with induction chemotherapy compared with concomitant chemoradiation (relative risk, 1.52; 95% confidence interval, 1.20–1.92). This study showed no benefit of induction chemotherapy + chemoradiation on overall survival. However, improved complete response rate and death certificate–only registrations may imply that selected patients may benefit from induction chemotherapy.


BMJ | 2015

Doctor-patient hierarchy may have a therapeutic role

Dror Limon; Salomon M. Stemmer

Use of the title “Doctor” preserves hierarchy in a patient-doctor relationship.1 However, hierarchy does not necessarily mean lack of respect, and deferential status exists in the patient-doctor relationship, regardless of whether this term is used. A similar hierarchy and relationship exist when we consult a priest, imam, rabbi, or any …


Journal of Neuro-oncology | 2018

Brain metastasis in gastroesophageal adenocarcinoma and HER2 status

Dror Limon; Omer Gal; Noa Gordon; Lior H. Katz; Gali Perl; Ofer Purim; Limor Amit; Salomon M. Stemmer; Yulia Kundel; Irit Ben-Aharon; Baruch Brenner; Tali Siegal; Shlomit Yust-Katz

The increased survival of patients with gastroesophageal adenocarcinoma (GAD) following improvements in treatment has been accompanied by a rising incidence of secondary brain metastasis. HER2 amplification/overexpression, which has been associated with an increased risk of brain metastasis in breast cancer, is found in about 20% of patients with GAD. The aim of this study was to evaluate the effect of HER2 status on brain metastasis in GAD. The database of a tertiary cancer center was searched for patients with GAD diagnosed in 2011–2015, and data were collected on clinical characteristics, brain metastasis, HER2 status, and outcome. We identified 404 patients with a confirmed diagnosis of GAD. HER2 results were available for 298: 69 (23.2%) positive and 227 negative. Brain metastasis developed in 15 patients with GAD (3.7%); HER2 results, available in 13, were positive in 6, negative in 6, and equivocal in 1. The brain metastasis rate was significantly higher in HER2-positive than HER2-negative patients with GAD (6/69, 8.7% vs. 6/227, 2.6%; RR = 3.3, 95% CI 1.1–9.9, p = 0.034). Median overall survival from diagnosis of brain metastasis was 2.3 months, with no significant difference by HER2 status. HER2 positive GAD patients may be at increased risk to develop BM. Clinicians should maintain a lower threshold for performing brain imaging in patients with HER2-positive GAD given their increased risk of brain metastasis. The role of anti-HER2 agents in the development and treatment of brain metastasis in GAD warrants further study.


Laryngoscope | 2016

Brachytherapy for radiotherapy-resistant head and neck cancer: A review of a single center experience

Inbal Hazkani; Naomi Rabinovics; Dror Limon; David Silvern; Sion Koren; Tuvia Hadar; Gideon Bachar; Thomas Shpitzer; Aron Popovtzer

Despite advances in radiotherapy and chemotherapy treatments for head and neck cancers, the local failure rate is high. In most radiotherapy‐resistant cases, surgery is performed; however, some cases are considered unresectable. No standard treatment for these situations has been established. In this study, we review our experience with brachytherapy (BT), which has a different biological mechanism than standard radiotherapy.

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Deborah T. Blumenthal

Tel Aviv Sourasky Medical Center

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Felix Bokstein

Tel Aviv Sourasky Medical Center

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