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Featured researches published by Dundar Sabah.


Skeletal Radiology | 1997

Liposarcoma of soft tissue: MRI findings with pathologic correlation

Remide Arkun; A. Memis; Taner Akalin; Esin Emin Üstün; Dundar Sabah; Gulsen Kandiloglu

ObjectiveTo evaluate the MRI findings of liposarcomas of different histologic types and correlate these with the histopathologic features.DesignThe MR images of seven liposarcomas were reviewed retrospectively to assess the tumor size, location, margination, signal characteristics and enhancement patterns in different histologic types.PatientsSeven liposarcomas comprising three well-differentiated, two myxoid and two pleomorphic types were evaluated.Results and conclusionAll tumors showed well-defined and mostly lobulated margins. The well-differentiated liposarcomas were composed mainly of fat with septations or nodules, were hyperintense on T2-weighted images, and demonstrated faint enhancement or no enhancement following intravenous contrast. Myxoid liposarcomas were homogeneous or mildly heterogeneous and a pseudocapsule was present in one case. Pleomorphic types showed a markedly heterogeneous internal structure. Both myxoid and pleomorphic lesions-showed moderate or marked heterogeneous enhancement after contrast administration. Well-differentiated liposarcomas may be differentiated from other types of the tumor by their largely lipomatous appearance. The malignancy grade increases in parallel with tumor heterogeneity and contrast enhancement.


Acta Orthopaedica et Traumatologica Turcica | 2014

Effect of adjuvant therapies on recurrence in aneurysmal bone cysts

Burcin Kececi; Levent Küçük; Alovsat Isayev; Dundar Sabah

OBJECTIVE The aim of this study was to define the effective factors such as surgical method, age and cavity filling materials on local recurrence in the treatment of aneurysmal bone cysts. METHODS The study included 85 patients (mean age: 17.9 years) that received surgical treatment for primary aneurysmal bone cyst. Nine were treated with cyst excision and 76 with intralesional curettage. The intralesional curettage group was divided into 3 subgroups according to adjuvant therapies applied; the first group received no additional adjuvant therapy, the second group received additional high-speed burr and the third group received additional high-speed burr and alcohol/phenol adjuvant treatments. Bone graft or bone cement was used to fill in the cavity. Mean follow-up period was 107.5 months. Groups were analyzed statistically in terms of local recurrence. Onset of cyst in ages under 10 and 20 years were considered a negative prognostic factor and analyzed statistically. RESULTS Local recurrence occurred in 10 (11.8%) patients. Mean duration between the initial operation and recurrence was 10 months. There was no significant difference in terms of local recurrence among the surgical treatment groups, adjuvant therapy groups, age groups and bone graft and bone cement groups. CONCLUSION Careful curettage of the entire cyst wall remains the most important step in the intralesional treatment of aneurysmal bone cyst.


Acta Orthopaedica et Traumatologica Turcica | 2011

Prevalence of bone and soft tissue tumors

Guven Yuceturk; Dundar Sabah; Burcin Kececi; Ahmet Duran Kara; Selçuk Yalçinkaya

OBJECTIVE Multidisciplinary approach is a necessity for the appropriate diagnosis and treatment of bone and soft tissue tumors. The Ege University Musculoskeletal Tumor Council offers consultation services to other hospitals in the Aegean region. Since 1988 the Council has met weekly and spent approximately 1,500 hours evaluating almost 6,000 patients with suspected skeletal system tumors. Our objective was to present the data obtained from this patient group. METHODS A total of 5,658 patients, suspected to have a musculoskeletal tumor, were evaluated retrospectively. Multiple records of the patients due to multiple attendance to the Council were excluded. The prevalance of the bone and soft tissue tumors in these patients were analysed. RESULTS Malignant mesenchymal tumors accounted for 39.7% of the total patients, benign tumors for 17%, tumor-like lesions for 17.8% and metastatic carsinomas for 8.6%. Malignant bone tumors were 50.2% and malignant soft tissue tumors were 49.8% of all the sarcomas. Among the malignant bone tumors the most common was osteosarcomas at a rate of 33.6%, followed by Ewing-PNET at 25.5%, chondrosarcomas at 19.4% and haematopoietic tumors at 17.6%. Pleomorphic sarcomas (24.5%), liposarcoma (16.4%), synovial sarcoma (13%) and undifferential sarcomas (8.8%) were the most common types of malignant sof tissue tumors. Benign soft tissue tumors (48%), benign cartilage tumors (28%), giant cell tumor (15%) and osteogenic tumors (9%) were found among the benign tumors. Hemangioma, lipoma, agressive fibromatosis, enchondroma, solitary chondroma and osteoid osteoma were the most common tumors in their groups. Lung (27%), breast (24%), gastrointestinal system (10.5%) and kidney (8.2%) carcinomas were the most common primary sites of the bone metastasis. CONCLUSION Turkey still lacks a comprehensive series indicating the incidence and diagnostic distribution of bone and soft tissue tumors. The presented data would add to our knowledge on the specific rates of the bone and soft tissue tumors in Aegean region.


European Radiology | 2002

Clear cell chondrosarcoma: unusual radiologic appearances with histologic correlation

A. Memis; Remide Arkun; Gulcin Basdemir; Dundar Sabah; Esin Emin Üstün

Abstract. Clear cell chondrosarcoma is a rare variant of the bone tumors with distinct radiologic and pathologic features. In this report two cases of clear cell chondrosarcomas with atypical radiologic appearances are presented. The findings of X-ray films and MRI are described with histologic correlation. In the first case the lesion showed a very expansile and long segment involvement of the humerus. In the second case the lesion was located in the diaphysis of the femur causing a large cortical destruction.


Acta Orthopaedica et Traumatologica Turcica | 2014

Aggressive fibromatosis: evaluation of prognostic factors and outcomes of surgical treatment

Levent Küçük; Burcin Kececi; Dundar Sabah; Guven Yuceturk

OBJECTIVE The aim of this study was to evaluate the results of surgical treatment of aggressive fibromatosis and the effects of prognostic factors on recurrence. METHODS Forty patients (24 female, 16 male; average age: 31.2 years) diagnosed with aggressive fibromatosis were evaluated retrospectively. Nine patients with tumor-positive surgical margins macroscopically were excluded. Prognostic factors such as age, gender, localization, admission status, compartment status, surgical margin, tumor size and adjuvant radiotherapy were evaluated. RESULTS Recurrence rate was 29%. Average disease free survival was 46±4 months. There was no statistically significant relation between prognostic factors and recurrence. Clinical results of the patients receiving adjuvant radiotherapy were more satisfactory. CONCLUSION Adjuvant radiotherapy administration appears to be a rational treatment method instead of sacrificing function to achieve wide surgical margins.


Acta Radiologica | 2009

Multidetector-Row Computed Tomographic Angiography Findings of Musculoskeletal Tumors: Retrospective Analysis and Correlation with Surgical Findings

Mehmet Argin; H. Isayev; Burcin Kececi; Remide Arkun; Dundar Sabah

Background: Although magnetic resonance imaging (MRI) is a valuable method in staging musculoskeletal tumors, it may not give enough information on the association between the tumor and the main vascular structures adjacent to the tumor. In this respect, computed tomographic angiography (CTA) may be a useful alternative imaging technique. Purpose: To evaluate the effectiveness of CTA in determining vascular invasion in patients with musculoskeletal tumors and suspected vascular invasion by MRI, and to correlate the CTA findings with the surgical findings. Material and Methods: Twenty patients who had musculoskeletal tumors and lacked a fat plane between the tumor and adjacent vessels by MRI were included in this study. All patients were evaluated with CTA, and the CTA findings were reviewed by two radiologists to determine the presence of vascular invasion. Statistical analysis was carried out by using surgical findings as the gold standard. Results: There were nine women and 11 men (mean age 31 years) with either bone (n=9) or soft-tissue (n=11) tumors. Twelve patients without invasion according to the CTA examination were also surgically negative (true-negative cases). Of the eight patients with invasion shown by CTA, only three had adhesions and were considered surgically negative (false-positive cases). Five had invasions proven by surgery and were considered surgically positive (true-positive cases). Compared to the surgical findings, CTA had 100% sensitivity, 80% specificity, 62.5% positive predictive value, 100% negative predictive value, and 80% accuracy. Conclusion: CTA is a more accurate imaging technique than MRI in evaluating vascular invasion of musculoskeletal tumors, and provides valuable preoperative data.


Blood Coagulation & Fibrinolysis | 2012

Acquired activated protein C resistance in sarcoma patients.

Nur Soyer; Burcin Kececi; Zuhal Eroglu; Serra Kamer; Cagri Ozcelik; Seckin Cagirgan; Murat Tombuloglu; Dundar Sabah; Ayhan Donmez

Acquired activated protein C resistance (aAPCR) is seen more frequently in solid and hematological cancer patients. We aimed to investigate the presence of aAPCR and the frequency of clinically detectable thrombosis in sarcoma patients. Normalized activated protein C sensitivity ratio (nAPCSR), factor V Leiden (FVL) mutation, factor V (FV) levels and factor VIII (FVIII) levels were prospectively measured in 52 patients and in 52 healthy controls. Clinically detectable thrombosis was present in one patient (1.92%). Compared with healthy controls (106%), the sarcoma patients had significantly lower values of the nAPCSR at pre (87.25%) and post (94.35%) treatment period (P < 0.0001). aAPCR was found as 4.2, 13 and 0%, respectively. The post-treatment FV levels (178.1 U/dl) were significantly (P < 0.001) higher than the pretreatment levels (147.5 U/dl). Inverse correlation was found between post-treatment FV levels and nAPCSR values (r = −0.38, P < 0.02). We found out a slightly increased frequency of venous thromboembolism in sarcoma patients. As an original finding which has not been reported previously in the literature, we also found out a decrease in the nAPCSR, persisting even after treatment. Thirdly, we found out that the significantly higher rate of aAPCR at the time of diagnosis totally disappeared after treatment.


Pediatric Hematology and Oncology | 2002

Treatment results of osteosarcoma of the extremity in children and adolescents at Ege University Hospital.

Mehmet Kantar; Nazan Çetingül; Sertaç Azarsíz; Dundar Sabah; A. Memis; Gulcin Basdemir; Zeynep Burak

Twenty-five patients were treated for osteosarcoma of the extremity at Ege University Hospital. Eight of them were metastatic. All patients received cisplatin, doxorubicin, ifosfamide, and methotrexate preoperatively. Twenty-three patients underwent surgery at around week 15 (11-18 weeks). All but one underwent limb-sparing surgery. While good responders continued to receive the same drugs, poor responders were given the same regimen before 1996, but high-dose ifosfamide alone after 1996. For all patients the projected event-free survival (EFS) rates were 63.5% at 2 years and 53% at 5 years. The projected overall survival (OS) rates were 72% at 2 years and 62% at 5 years. For nonmetastatic patients, 5-year EFS and OS rates were 67% as compared with metastatic patients (25 and 50%)( p = .01 for EFS; p > .05 for OS). The results show that nonmetastatic patients with osteosarcoma of the extremity have favorable prognosis on this therapy regimen, allowing a high rate of limb-sparing surgery.


Tumori | 2016

The role of radiotherapy in local control of nonextremity Ewing sarcomas.

Özlem Akagündüz; Serra Kamer; Burcin Kececi; Bengü Demirağ; Haldun Öniz; Mehmet Kantar; Nazan Çetingül; Dundar Sabah; Yavuz Anacak

Purpose To evaluate the results of radiotherapy and the prognostic factors affecting local control in nonextremity Ewing sarcomas. Methods Between 1995 and 2011, 44 patients with nonextremity Ewing sarcomas were treated with radiotherapy. Tumor localizations were pelvis in 23, spine in 13, thoracic region in 5, and cranium in 3 patients. Tumor size was ≥8 cm in 56.8% of patients. Distant metastases were present in 19 of the patients at the time of diagnosis (43.1%). All patients were treated with 12 weeks of neoadjuvant chemotherapy followed by surgery and radiotherapy (45-54 Gy) or radiotherapy alone (54-64.8 Gy). Radiotherapy was applied due to microscopic residue (R1) in 5 patients after the operation and macroscopic tumor in 39 patients (macroscopic residue [R2] and nonresectable tumor). Results Median follow-up was 49 months (range 9-195). Local failures developed in 7 patients (15.9%) and local control at 5 years was 81.4%. Local recurrence was detected in 6 patients (6/38) who did not have residual tumor after RT. Progression was detected in 1 patient (1/6) who had residual tumor. All those patients with local failure experienced further distant metastases. Possible prognostic factors such as age (≤17 vs >17), tumor localization, tumor volume (≤8 cm vs >8 cm), and M status at diagnosis (0 vs 1) were not related to local control. Conclusions Radiotherapy, either alone or adjuvant to surgery, provides local control in 80% of nonextremity Ewing sarcomas and plays an important role in treatment.


European Journal of Nuclear Medicine and Molecular Imaging | 2001

The role of 99mTc-MIBI scintigraphy in the assessment of MDR1 overexpression in patients with musculoskeletal sarcomas: comparison with therapy response

Zeynep Burak; Özden Ersoy; Jean-Luc Moretti; Rüya Erinç; Zehra Özcan; Aysegul Dirlik; Dundar Sabah; Gulcin Basdemir

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