Mahmut Ozsahin

Dr. Mahmut Ozsahin


Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2006 in International Journal of Radiation Oncology - Biology - Physics (IJROBP)
Verified
Journal Article
Closed access
MOMahmut Ozsahin
Mahmut Ozsahin
RTRichard W. Tsang
Richard W. Tsang
PPPhilip Poortmans
Philip Poortmans
YBYazid Belkacémi
Yazid Belkacémi
MBMichel Bolla
Michel Bolla
AZAbderrahim Zouhair
Abderrahim Zouhair

2 May 2006 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
MZMichel Zimmermann
Michel Zimmermann
AZAbderrahim Zouhair
Abderrahim Zouhair
DADavid Azria
David Azria
MOMahmut Ozsahin
Mahmut Ozsahin
Epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptors. Its stimulation by endogenous ligands, EGF or transforming growth factor-alpha (TGF-α) results in activation of intracellular tyrosine kinase, therefore, cell cycle progression. High levels of EGFR expression are correlated with poor prognosis and resistance to radiation therapy in a variety of cancers, mostly in squamous-cell carcinoma of the head and neck (SCCHN). Blocking the EGFR by a monoclonal antibody results in inhibition of the stimulation of the receptor, therefore, in inhibition of cell proliferation, enhanced apoptosis, and reduced angiogenesis, invasiveness and metastases. The EGFR is a prime target for new anticancer therapy in SCCHN, and other agents in development include small molecular tyrosine kinase inhibitors and antisense therapies.

5 May 2006 in BMC Cancer
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Journal Article
Open access
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DKDavid Knobel
David Knobel
AZAbderrahim Zouhair
Abderrahim Zouhair
RTRichard W Tsang
Richard W Tsang
PPPhilip Poortmans
Philip Poortmans
YBYazid Belkacémi
Yazid Belkacémi
FNFor The Rare Cancer Network
For The Rare Cancer Network
Background: Solitary plasmacytoma (SP) of the bone is a rare plasma-cell neoplasm. There are no conclusive data in the literature on the optimal radiation therapy (RT) dose in SP. Therefore, in this large retrospective study, we wanted to assess the outcome, prognostic factors, and the optimal RT dose in patients with SP.Methods: Data from 206 patients with bone SP without evidence of multiple myeloma (MM) were collected. Histopathological diagnosis was obtained for all patients. The majority (n = 169) of the patients received RT alone; 32 chemotherapy and RT, and 5 surgery. Median follow-up was 54 months (7–245).Results: Five-year overall survival, disease-free survival (DFS), and local control was 70%, 46%, and 88%; respectively. Median time to MM development was 21 months (2–135) with a 5-year probability of 51%. In multivariate analyses, favorable factors were younger age and tumor size < 5 cm for survival; younger age for DFS; anatomic localization (vertebra vs. other) for local control. Older age was the only predictor for MM. There was no dose-response relationship for doses 30 Gy or higher, even for larger tumors.Conclusion: Younger patients, especially those with vertebral localization have the best outcome when treated with moderate-dose RT. Progression to MM remains the main problem. Further investigation should focus on adjuvant chemotherapy and/or novel therapeutic agents.

1 November 2010 in International Journal of Radiation Oncology - Biology - Physics (IJROBP)
Verified
Journal Article
Closed access
MOMahmut Ozsahin
Mahmut Ozsahin
GGGuenther Gruber
Guenther Gruber
OOOlimpia Olszyk
Olimpia Olszyk
OKOmur Karakoyun-Celik
Omur Karakoyun-Celik
BPBerrin Pehlivan
Berrin Pehlivan
AZAbderrahim Zouhair
Abderrahim Zouhair

16 March 2016 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
FHFernanda G. Herrera
Fernanda G. Herrera
TBThomas Breuneval
Thomas Breuneval
John PriorJohn Prior
John Prior
Jean BourhisJean Bourhis
Jean Bourhis
MOMahmut Ozsahin
Mahmut Ozsahin
To compare the prognostic value of different anatomical and functional metabolic parameters determined using [18F]FDG-PET/CT with other clinical and pathological prognostic parameters in cervical cancer (CC). Thirty-eight patients treated with standard curative doses of chemo-radiotherapy (CRT) underwent pre- and post-therapy [18F]FDG-PET/CT. [18F]FDG-PET/CT parameters including mean tumor standardized uptake values (SUV), metabolic tumor volume (MTV) and tumor glycolytic volume (TGV) were measured before the start of CRT. The post-treatment tumor metabolic response was evaluated. These parameters were compared to other clinical prognostic factors. Survival curves were estimated by using the Kaplan-Meier method. Cox regression analysis was performed to determine the independent contribution of each prognostic factor. After 37 months of median follow-up (range, 12–106), overall survival (OS) was 71 % [95 % confidence interval (CI), 54–88], disease-free survival (DFS) 61 % [95 % CI, 44–78] and loco-regional control (LRC) 76 % [95 % CI, 62–90]. In univariate analyses the [18F]FDG-PET/CT parameters unfavorably influencing OS, DFS and LRC were pre-treatment TGV-cutoff ≥562 (37 vs. 76 %, p = 0.01; 33 vs. 70 %, p = 0.002; and 55 vs. 83 %, p = 0.005, respectively), mean pre-treatment tumor SUV cutoff ≥5 (57 vs. 86 %, p = 0.03; 36 vs. 88 %, p = 0.004; 65 vs. 88 %, p = 0.04, respectively) and a partial tumor metabolic response after treatment (9 vs. 29 %, p = 0.0008; 0 vs. 83 %, p < 0.0001; 22 vs. 96 %, p < 0.0001, respectively). After multivariate analyses a partial tumor metabolic response after treatment remained as an independent prognostic factor unfavorably influencing DFS and LRC (RR 1:7.7, p < 0.0001, and RR 1:22.6, p = 0.0003, respectively) while the pre-treatment TGV-cutoff ≥562 negatively influenced OS and DFS (RR 1:2, p = 0.03, and RR 1:2.75, p = 0.05). Parameters capturing the pre-treatment glycolytic volume and metabolic activity of [18F]FDG–positive disease provide important prognostic information in patients with CC treated with CRT. The post-therapy [18F]FDG-PET/CT uptake (partial tumor metabolic response) is predictive of disease outcome.

1 December 2014 in International Journal of Radiation Oncology - Biology - Physics (IJROBP)
Verified
Journal Article
Closed access
OEOlgun Elicin
Olgun Elicin
SCSharon Callaway
Sharon Callaway
John PriorJohn Prior
John Prior
Jean BourhisJean Bourhis
Jean Bourhis
MOMahmut Ozsahin
Mahmut Ozsahin
FHFernanda G. Herrera
Fernanda G. Herrera