Publications by authors named "Aysen Dizman"

10 Publications

  • Page 1 of 1

Computed Tomography-Guided Optimization of Needle Insertion for Combined Intracavitary/Interstitial Brachytherapy With Utrecht Applicator in Locally Advanced Cervical Cancer.

Pract Radiat Oncol 2021 Jul-Aug;11(4):272-281. Epub 2021 Feb 5.

Liv Hospital Ulus, Department of Radiation Oncology, Istanbul, Turkey; Istinye University, Faculty of Medicine, Department of Radiation Oncology, Istanbul, Turkey.

Purpose: There are no international guidelines for optimal needle insertion during interstitial intracavitary brachytherapy (IS-ICBT) for cervical cancer. We aimed to investigate the clinical feasibility and added value of computed tomography (CT) guidance to optimize needle insertion in IS-ICBT using the Utrecht applicator and to evaluate needle shifts.

Methods And Materials: We enrolled 24 patients who were treated with interstitial-brachytherapy. Two CT scans each were performed for every patient: (1) after applicator insertion without needles (CT) and (2) after needle insertion (CT). In addition to magnetic resonance imaging after external-beam radiation therapy, CT was used to determine optimal needle locations and insertion lengths based on applicator and organs at risk positioning on the day of treatment; CT was used for IS-ICBT planning. The needle-channel axis was used as a reference to determine needle-shift evolution.

Results: A total of 266 interstitial needles were inserted in 76 of 93 BT fractions with high intra- and interpatient variations in the number of inserted needles. Based on CT findings, needle insertion was avoided in 9, 4, 2, and 2 patients at the first, second, third, and fourth fractions, respectively. The unloaded needle frequency was 4%. Average needle contribution to total dwell time was 37.2% ± 19.2%. Shifting was observed in 68% of the needles (mean shift 2.0 ± 2.3 mm), mostly in the posterior direction, and in needles with a larger insertion length. Needle reinsertion was not needed in any patient. No complication due to needle insertion was observed, except for minor vaginal bleeding in 1 patient after needle removal.

Conclusions: The adaptive CT-guided IS-ICBT application was feasible and resulted in fewer unloaded needle insertions or complications and more efficient use with higher needle contribution to the treatment. Needle shift was frequent but did not require needle reinsertion with the proposed method.
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http://dx.doi.org/10.1016/j.prro.2021.01.008DOI Listing
February 2021

Challenges and differences in external radiation therapy for retinoblastoma: from standard techniques to new developments.

Tumori 2017 Sep 28;103(5):438-442. Epub 2015 Aug 28.

Department of Radiation Oncology, Ankara University School of Medicine, Cebeci Hospital, Ankara - Turkey.

Aims: The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife).

Methods: Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique.

Results: All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT.

Conclusions: This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.
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http://dx.doi.org/10.5301/tj.5000406DOI Listing
September 2017

A rare type of cancer in children: extranodal marginal zone B-cell (MALT) lymphoma of the ocular adnexa.

Turk J Pediatr 2014 May-Jun;56(3):295-8

Department of Pediatric Oncology, Konya Training and Research Hospital, Konya, Turkey.

Primary ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphomas (OAMLs) are mostly seen in the 5th-7th decades of life, with female predominance, and they occur rarely in children. Thus, knowledge about this cancer type is obtained from adult data in the literature, while the data regarding OAMLs in the pediatric population are limited to a few case reports. Herein, we report a 10-year-old boy with OAML who was treated successfully with radiotherapy, and we discuss this uncommon lymphoma in children.
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March 2016

Practice patterns for oropharyngeal cancer in radiation oncology centers of Turkey.

Tumori 2014 May-Jun;100(3):284-8

Aims And Background: The aim of the study was to review the current clinical practices of radiation oncologists involved in the treatment of oropharyngeal cancer.

Methods And Study Design: The daily practices of radiation oncology centers for patients diagnosed with oropharyngeal cancer in 2010 were evaluated by a two-part questionnaire that separately assessed the information of the participating center and the charts of the treated patients.

Results: A total of 22 centers participated in the study, and 105 oropharyngeal cancer patients reported for our review. The use of positron emission tomography was a common practice in staging and radiotherapy planning. Multidisciplinary head and neck cancer clinics were available in 14 (64%) centers and were absent in 8 centers. Thirty-six of the 105 patients were not evaluated by a multidisciplinary clinic before the initiation of therapy, and adjuvant radiotherapy administration was found to be higher in this group. Percutaneous endoscopic gastrostomy tube placement was not a routine practice in any of the centers. Seventy-five patients received chemotherapy - 46 concurrently with radiotherapy and 29 as induction chemotherapy. Two centers administered conventional radiotherapy alone, 20 centers conformal radiotherapy, and 7 centers were able to provide intensity-modulated radiotherapy.

Conclusions: Across all the centers there were small differences in the pretreatment evaluation of patients with oropharyngeal cancer. The greatest difference was in the technical delivery of radiation, with most of the centers using conformal radiotherapy despite the increasing availability of intensity-modulated radiotherapy. The use of chemotherapy has more readily adopted the current international standards in the treatment of oropharyngeal cancer.
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http://dx.doi.org/10.1700/1578.17204DOI Listing
November 2014

Reirradiation with robotic stereotactic body radiotherapy for recurrent nasopharyngeal carcinoma.

Asian Pac J Cancer Prev 2014 ;15(8):3561-6

Radiation Oncology, Ankara Oncology Hospital, Ankara, Turkey E-mail :

Background: Recurrent nasopharyngeal carcinoma (NPC) after previous radiotherapy is challenging. There is no standard approach for salvage treatment. Here we present toxicity and treatment results for recurrent NFC patients who underwent fractionated stereotactic radiotherapy (FSRT) as second line radiotherapy (RT).

Materials And Methods: Between April 2009 and July 2012, 24 patients, with a male to female ratio of 3:1, were treated with CykerKnife® FSRT for recurrent NFC in our institution. Seven out of 24 patients had metastatic recurrent disease. Median age was 53 years (range, 20-70 years). Initial RT dose was 70Gy. The time period between initial RT and FSRT was a median of 33.2 months. The median prescription dose for FSRT was 30Gy (range, 24-30 Gy) in a median of 5 fractions (range, 4-6).

Results: The median follow-up for all patients was 19.5 months (IQR: 12.2. -29.2 months). The locoregional control; progression free survival and overall survival (OS) rates for 1-, 2- and 3-year were 64%, 38%, 21%; 60%, 30%, 17% and 83%, 43%, 31%, respectively. Median OS for the entire cohort was 22 months (95% CI: 16.5-27.5). On multivariate analysis recurrent tumor stage was the only prognostic factor for OS (p=0.004). One patient exhibited grade III temporal lobe necrosis. One died because of grade IV mucositis and overlapping infection.

Conclusions: The treatment of recurrent NPC is controversial. Fractionated stereotactic radiotherapy is promising. However, the published trials are heterogeneous with respect to the selection criteria and treatment details. Prospective studies with long term follow-up data are warranted.
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http://dx.doi.org/10.7314/apjcp.2014.15.8.3561DOI Listing
January 2015

Comparison of early oncological results of diode laser surgery with radiotherapy for early glottic carcinoma.

Otolaryngol Head Neck Surg 2014 May 31;150(5):818-23. Epub 2014 Jan 31.

Ankara Oncology Education and Research Hospital, Clinic of Otolaryngology, Ankara, Turkey.

Objective: To evaluate the oncologic results of transoral endolaryngeal microscopic diode laser surgery (MDLS) and radiotherapy (RT) for T1 and T2 glottic carcinoma.

Study Design: Case series with planned chart review.

Setting: Ankara Oncology Education and Research Hospital.

Subjects And Methods: The study was conducted on a series of 140 cases of early glottic carcinoma (T1, T2) treated with MDLS or RT. The tumors were defined according to T stage and the involvement of the anterior commissure (AC).

Results: The 3-year locoregional control rate of MDLS and RT groups was 93.1% and 89.7%, respectively (P = .434). There was no difference in 3-year disease-free survival when comparing T1 and T2 tumors treated with MDLS and those treated with RT (P = .618 for T1, P = .084 for T2). There was no difference in disease-free survival when comparing AC- and AC+ tumors treated with MDLS and those treated with RT (P = .291 for AC- and P = .530 for AC+ tumors).

Conclusions: Microscopic diode laser surgery in early glottic cancer seems to be an oncologically safe procedure that has similar oncological results with RT. In T2 glottic tumors and AC involvement, the results with either treatment are less satisfactory.
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http://dx.doi.org/10.1177/0194599814521775DOI Listing
May 2014

Do clinical characteristics and metabolic markers detected on positron emission tomography/computerized tomography associate with persistent disease in patients with in-operable cervical cancer?

Ann Nucl Med 2013 Oct 21;27(8):756-63. Epub 2013 Jun 21.

Department of Nuclear Medicine, Ankara Oncology Research and Training Hospital, Ankara, Turkey.

Unlabelled: The objective of this retrospective study was to evaluate the prognostic significance of volume-based metabolic markers of PET/CT along with clinical characteristics in patients with in-operable cervical carcinoma.

Methods: Fifty-eight patients with cervical carcinoma (stage IIB-IVB) underwent FDG PET/CT for pretreatment evaluation and included in this study. Patients were staged according to International Federation of Gynecology and Obstetrics [FIGO] system. After chemoradiation therapy, patients were evaluated for persistent disease (PD) by clinical examinations, smear tests, pelvic MRI and PET/CT. Based upon follow-up results, clinical characteristics (patient age, tumor histology, FIGO stage) and PET/CT findings such as presence of PET-positive pelvic/para-aortic lymph nodes (LN), metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake values (SUVmax) of tumor and lymph nodes were analyzed for disease persistence. Survival analysis for disease-free survival and overall survival was performed with Kaplan-Meier method using PET findings and clinical characteristics.

Results: At the time of last follow-up (mean: 22 ± 12.6 months, range 6-48), 38 patients (65 %) had PD, 20 patients (35 %) had no evidence of disease (NED). Patient age, tumor histology, MTV, TLG and tumor SUVmax did not differ between groups. The frequency of PET-positive pelvic/para-aortic lymph nodes (84 vs. 60 %, p = 0.03), LN SUVmax (10.2 vs. 6.5, p = 0.02), and FIGO stage differed significantly between PD and NED groups. Cox proportional hazards model demonstrated advanced FIGO stage and the presence of PET-positive para-aortic LN were independent predictors for PD. Both disease-free survival and overall survival curves showed progressive worsening as the disease advanced, p = 0.015. PET LN status was the most important prognostic indicator for disease-free survival and overall survival. The worst outcome curves were detected for patients with PET-positive para-aortic lymph nodes among all patients, p = 0.03.

Conclusion: Advanced FIGO stage and the presence of FDG-avid para-aortic lymph nodes on pretreatment PET/CT are significant prognostic biomarkers for PD and decreased overall survival in patients with in-operable cervical carcinoma independent from MTV, TLG, tumor and lymph node SUVmax.
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http://dx.doi.org/10.1007/s12149-013-0745-1DOI Listing
October 2013

Optic nerve glioma treatment with fractionated stereotactic radiotherapy.

J Neurosurg Pediatr 2013 May 15;11(5):596-9. Epub 2013 Mar 15.

Clinic of Radiation Oncology, Dr. Abdurrahman Yurtarslan Ankara Oncology Education and Research Hospital, Demetevler, Ankara, Turkey.

In the current report, the authors present a case of optic nerve glioma treated with fractionated stereotactic radiotherapy (FSRT). An 11-year-old girl was referred to our clinic with increasing proptosis over a 1-year period. At that time orbital MRI revealed a 20 × 17-mm mass in the right retroorbital lipomatous tissue, and FSRT was delivered to the tumor using the CyberKnife. During the 1.5-year follow-up, ophthalmological examinations did not indicate any treatment-related severe toxicity, and posttreatment MRI demonstrated marked regression of the lesion to 13 × 10 mm. Given the scarcity of reports on this subject, the authors support more extended studies of the CyberKnife for the effective treatment of this relatively common childhood tumor.
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http://dx.doi.org/10.3171/2013.2.PEDS11435DOI Listing
May 2013

Nasopharyngeal carcinomas: prognostic factors and treatment features.

J Egypt Natl Canc Inst 2008 Sep;20(3):230-6

The Departments of Radiology, Ankara Oncology Education and Research Hospital, Ankara, Turkey.

Purpose: We retrospectively evaluated the clinical, radiological and pathological features determining the prognosis of patients with nasopharyngeal carcinoma in Ankara Oncology Hospital, Turkey.

Material And Methods: Two hundred and fifty-nine patients, 74 women and 185 males with nasopharyngeal carcinoma were treated between 1993 and 2008. All imaging data including CT and MRI were reevaluated according to the criteria which determine parapharyngeal, oropharyngeal, nasal, skull-base (bone)/sinus, infratemporal fossa, orbit, intracranial involvements and lymph node metastasis by our radiologists. The patients were restaged using the AJCC 2002 classification with these new radiological findings and clinical data base. We evaluated prognostic factors using univariate Kaplan- Meier and multivariate Cox regression analyses. Gender, age (40-year cut-off), histology, T- and N-stage, tumor size, regional involvement, radiotherapy and/or chemotherapy and response to therapy were studied as variables.

Results: Five-year disease-free and overall survival rates were 45 +/- 4 % and 72 +/- 3 % , respectively. We found that age, gender, WHO type, radiotherapy and/or chemotherapy, N-stage and response to therapy were significant prognostic factors on disease-free survival and overall survival. In the chemo-radiotherapy group, we did not detect any survival difference between patients given four or fewer chemotherapy courses.

Conclusions: Radiotherapy improved survival but chemotherapy, in the neoadjuvant and adjuvant setting, had no added effect to radiotherapy. N-stage and response to treatment were the most important independent predictors on survival. Age, gender, type, therapy and bone/sinus involvement were among the predictive factors on multivariate analysis, as well.

Key Words: Nasopharyngeal carcinoma - Prognostic factor - MRI - CT - Radiotherapy - Chemotherapy.
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September 2008

Effects of two different high doses of irradiation on antioxidant system in the liver of guinea pigs.

Eksp Onkol 2004 Mar;26(1):71-4

Gazi University Medical Faculty Department of Biochemistry, Ankara, Turkey.

Aim: To examine the state of the oxidant-antioxidant system in the liver of guinea pig caused by high doses of ionizing radiation in the early period.

Methods: The research was carried out on guinea pigs irradiated with the doses of 8 Gy (group 2) or 15 Gy (group 3) (single dose/whole body) in comparison with control group (group 1). The levels of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH), the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the levels of selenium in the liver were measured.

Results: TBARS levels in the irradiated animals were markedly higher than those in controls. In group 3, GSH levels and GSH-Px activity were significantly increased while activity of SOD and CAT were significantly decreased compared to groups 1 and 2. Liver selenium levels were not influenced by irradiation.

Conclusion: The data have shown that gamma-irradiation at the doses of 8 Gy or 15 Gy results in significant increase in free radical formation while antioxidant enzymes were affected only at a dose of 15 Gy.
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March 2004
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