Publications by authors named "Timur Koca"

17 Publications

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Dosimetric comparison of different treatment planning techniques with International Commission on Radiation Units and Measurements Report-83 recommendations in adjuvant pelvic radiotherapy of gynecological malignancies.

J Cancer Res Ther 2016 Apr-Jun;12(2):975-80

Department of Radiation Oncology, Akdeniz University School of Medicine, Antalya, Turkey.

Aim: The study evaluates the different treatment planning techniques according to three recommendation levels of the International Commission on Radiation Units and Measurements Report-83 in gynecologic cancer patients treated with adjuvant pelvic radiotherapy (APR).

Materials And Methods: Computerized tomography images of ten endometrial and cervical cancer patients who were treated with APR were assessed. For each patient, five different treatment plans were created. One homogeneity index and four different conformity indexes (CIs) were calculated for three-dimensional conformal radiotherapy (3D-CRT), field-in-field (FIF), seven-field intensity modulated radiotherapy (7-IMRT) with two different degrees beginning (7A-IMRT, 7B-IMRT) and 9-IMRT treatment plans. Dose volume histogram parameters and normal tissue complication probability (NTCP) were compared for organs at risk (OAR).

Results: The CI values of the IMRT were closer to 1 with respect to other plans (P < 0.05). The rectum and the bladder volumes which received more than 40 Gy were decreased with IMRT compared to 3D-CRT (P < 0.05). Doses received by the 195 cc volume of the small intestine and NTCP values were significantly decreased with IMRT (P < 0.05).

Conclusion: IMRT provided more protection than FIF plans at high dose volumes of the OAR; however, it did not show any superiority at low-dose volumes. The NTCP results supported IMRT for only small intestine protection. Because IMRT is increasingly used clinically, the comparison of NTCP will become more common in the near future. Therefore, new prospective studies with sufficient number of patients and appropriate NTCP models are needed for this treatment modality.
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http://dx.doi.org/10.4103/0973-1482.179189DOI Listing
March 2017

Prognostic factors in clinical stage T4N2 locally advanced non-small cell lung cancer.

J BUON 2015 Mar-Apr;20(2):573-9

Erzurum Research and Education Hospital, Medical Oncology Department, Erzurum, Turkey.

Purpose: Relatively few studies have focused on T4N2 (stage IIIB) locally advanced non-small cell lung cancer (NSCLC). In this study, we tried to identify prognostic factors for patients with clinical stage T4N2 NSCLC.

Methods: We retrospectively identified 223 patients, of which 168 met the inclusion criteria. Patients treated with curative intent using concurrent chemoradiotherapy (CRT) with or without adjuvant chemotherapy, or concurrent CRT after induction chemotherapy, were included in this study. Relevant patient, treatment, and disease factors were evaluated for their prognostic significance in both univariate and multivariate analyses using the Cox proportional hazards model.

Results: The median progression-free survival (PFS) was 13 months (95% confidence interval [CI], 10.6-15.4). The median overall survival (OS) was 20 months (95% CI, 16.8-23.1), and 71, 40.3 and 28.2% of the patients survived for 1, 2 and 3 years after diagnosis, respectively. Multivariate analysis showed Eastern Cooperative Oncology Group (ECOG) performance status (PS) was independent predictor of PFS (hazard ratio [HR], 0.24; 95% CI, 0.13-0.43; p=0.001), and OS [HR, 0.48; 95% CI, 0.26-0.87; p=0.015). Absence of multifocal T4 tumors was also associated with a significantly longer OS (HR, 046; 95% CI, 0.31-0.7; p=0.001). There was no statistically significant difference in OS and PFS between treatment modalities.

Conclusion: PFS and OS were significantly shorter in patients with poor ECOG PS. OS was also significantly shorter in patients with multifocal T4 tumors. There were no differences between the two therapeutic approaches with respect to outcome.
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July 2015

Treatment outcomes and survival study of gastric cancer patients: a retrospective analysis in an endemic region.

Asian Pac J Cancer Prev 2015 ;16(5):2055-60

Department of Radiation Oncology, Erzurum Regional Training and Research Hospital, Erzurum, Turkey E-mail :

Purpose: To present information about prognostic factors of gastric cancer patients treated in our Erzurum center including age, gender, tumour location, pathological grade, stage and the effect of treatment on survival.

Materials And Methods: This retrospective study was performed on patients who applied to our clinic and diagnosed as gastric cancer. Age and gender of the patients, primary location, histopathological characteristics, TNM stage of the gastric cancers (GCs), treatment applied, oncological treatment modalities and survival outcomes were studied. A univariate analysis of potential prognostic factors was performed with the log-rank test for categorical factors and parameters with a p value < 0.05 at the univariate step were included in the multivariate regression.

Results: A total of 228 patients with a confirmed diagnosis of gastric cancer were included in the study with a male/female ratio of 1.47. Median follow-up period was estimated as 22.3 (range, 3 to 96) months. When diagnosis of the patients at admission was analysed, stage III patients were most frequently encountered (n=147; 64.5%). One hundred and twenty-six (55.3%) underwent surgical treatment, while 117 (51.3%) were given adjuvant chemotherapy. Median overall survival time was 18.0 (± 1.19) months. Mean overall survival rates for 1, 2, 3 and 5 years were 68 ± 0.031%, 36 ± 0.033%, 24 ± 0.031% and 15.5 ± 0.036%, respectively. Univariate variables found to be significant for median OS in the multivariate analysis were evaluated with Cox regression analysis. A significant difference was found among TNM stage groups, location of the tumour and postoperative adjuvant treatment receivers (p values were 0.011, 0.025 and 0.001, respectively).

Conclusions: This study revealed that it is possible to achieve long-term survival of gastric cancer with early diagnosis. Besides, in locally advanced GC patients, curative resection followed by adjuvant concomitant chemoradiotherapy based on the McDonald regimen was an independent prognostic factor for survival.
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http://dx.doi.org/10.7314/apjcp.2015.16.5.2055DOI Listing
December 2015

Dietary and demographical risk factors for oesophageal squamous cell carcinoma in the Eastern Anatolian region of Turkey where upper gastrointestinal cancers are endemic.

Asian Pac J Cancer Prev 2015 ;16(5):1913-7

Department of Radiation Oncology, Regional Training and Research Hospital, Erzurum, Turkey E-mail :

Background: Oesophageal squamous cell carcinoma (ESCC) is endemic in the Eastern Anatolian region of Turkey. The present study was performed to identify risk factors for ESCC that specifically reflect the demography and nutritional habits of individuals living in this region.

Materials And Methods: The following parameters were compared in 208 ESCC patients and 200 control individuals in the Eastern Anatolian region: age, sex, place of living, socioeconomic level, education level, smoking, alcohol intake, nutritional habits, and food preservation methods.

Results: The mean age of ESCC patients was 56.2 years, and 87 (41.8%) were 65 years-old or older. The ratio of women to men in the patient group was 1.39/1. ESCC patients consumed significantly less fruit and yellow or green vegetables and more hot black tea, 'boiled yellow butter', and mouldy cheese than did control individuals. Residence in rural areas, smoking, and cooking food by burning animal manure were also significantly associated with ESCC.

Conclusions: The consumption of boiled yellow butter and mouldy cheese, which are specific to the Eastern Anatolian region, and the use of animal manure for food preparation were identified as risk factors in this region. Further studies are required to potentially identify the carcinogenic substances that promote the development of ESCC in this region.
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http://dx.doi.org/10.7314/apjcp.2015.16.5.1913DOI Listing
February 2016

Cancer pain prevalence and its management.

Asian Pac J Cancer Prev 2014 ;15(20):8557-62

Department of Medical Oncology, Regional Training and Research Hospital, Erzurum, Turkey E-mail :

Pain is a public health problem affecting more than half of cancer patients. Despite the success of the protocols currently used, pain cannot still be reduced satisfactorily in the large majority of patients. In order to improve pain management, all healthcare professionals involved with pain should have sufficient knowledge on pain assessment and treatment, and should inform patients to prevent patient-related barriers. In this compilation, the prevalence values and the treatment methods of cancer pain, and the barriers to pain management have been assessed.
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http://dx.doi.org/10.7314/apjcp.2014.15.20.8557DOI Listing
July 2015

Comparison of linear accelerator and helical tomotherapy plans for glioblastoma multiforme patients.

Asian Pac J Cancer Prev 2014 ;15(18):7811-6

Regional Training and Research Hospital, Department of Radiation Oncology, Erzurum, TurkeyE-mail :

Background: Despite advances in radiotherapy, overall survival of glioblastoma multiforme (GBM) patients is still poor. Moreover dosimetrical analyses with these newer treatment methods are insufficient. The current study is aimed to compare intensity modulated radiation therapy (IMRT) linear accelerator (linac) and helical tomotherapy (HT) treatment plans for patients with prognostic aggressive brain tumors.

Material And Methods: A total of 20 GBM patient plans were prospectively evaluated in both linac and HT planning systems. Plans are compared with respect to homogenity index, conformity index and organs at risk (OAR) sparing effects of the treatments.

Results: Both treatment plans provided good results that can be applied to GBM patients but it was concluded that if the critical organs with relatively lower dose constraints are closer to the target region, HT for radiotherapeutical application could be preferred.

Conclusion: Tomotherapy plans were superior to linear accelerator plans from the aspect of OAR sparing with slightly broader low dose ranges over the healthy tissues. In case a clinic has both of these IMRT systems, employment of HT is recommended based on the observed results and future re-irradiation strategies must be considered.
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http://dx.doi.org/10.7314/apjcp.2014.15.18.7811DOI Listing
June 2015

Impact of poster presentations on academic knowledge transfer from the oncologist perspective in Turkey.

Asian Pac J Cancer Prev 2014 ;15(18):7707-11

Department of Medical Oncology, Regional Teaching and Research Hospital, Erzurum, TurkeyE-mail :

Background: Currently poster presentations offer a common visual medium for knowledge transfer by a wide range of health professionals. Our study aimed to determine the scientific importance of poster presentations for Medical and Radiation Oncologists.

Methods: A survey form including 40 questions was distributed to a total of 131 oncologists experienced in poster presentations. One hundred completed survey forms were included in the study. Descriptive statistics and modified thematic analyses were performed on the responses.

Results: Overall 64% of the participants agreed that posters were a good medium for knowledge transfer. Some 88% agreed that concise and clear styled presentations would increase appealing interests for poster contents. Visual appearance was cited more influential than content of the subject; 70% of participants agreed that appearances of posters could help to draw more viewer attention. Of respondents, 63% believed that posters accompanied by their author were more attractive for congress attendees, and 33% of them declared that the halo effect of the poster presenter was also important.

Conclusion: The present study indicated that intelligibility, appearance and visuality of posters are most important factors from the aspect of oncologist participants. Presenters must take into account these important points when preparing their academic posters.
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http://dx.doi.org/10.7314/apjcp.2014.15.18.7707DOI Listing
June 2015

Prominent response with helical tomotherapy in recurrent ameloblastic carcinoma of maxillary sinus: a case report.

Radiat Oncol 2014 Jul 15;9:157. Epub 2014 Jul 15.

Department of Radiation Oncology, Regional Training and Research Hospital, Erzurum, Turkey.

Introduction: Ameloblastoma is a benign but locally aggressive tumor of odontogenic epithelial tissue. Reports of radiotherapy treatment modalities are limited in the literature.

Case Presentation: A thirty-five year old male presented with complaints of headache radiating to his face for about six months and impaired vision. The patient's Positron Emission Tomography (PET) showed a mass in the left maxillary sinus extending to the nasal cavity and invading the adjacent tissues. An R2 (macroscopic residual tumor) surgical resection performed to debulk the tumor. Due to the recurrence and residual mass, the patient was treated with helical tomotherapy. At 2 months post-radiotherapy, patient's vision returned to normal. PET scan showed a significant reduction in lesion size 12 months post-radiation.

Conclusion: In cases of ameloblastic carcinoma with, post-surgical recurrence or patients not suitable for surgical treatment, helical tomotherapy can be an effective treatment option.
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http://dx.doi.org/10.1186/1748-717X-9-157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108973PMC
July 2014

Painful plantar heel spur treatment with Co-60 teletherapy: factors influencing treatment outcome.

Springerplus 2014 10;3:21. Epub 2014 Jan 10.

Regional Training and Research Hospital Radiation Oncology Department, Caykara caddesi, Erzurum, 25200 Turkey.

Background: Painful plantar heel spur (PPHS) is a benign disorder with painful heels as a result of plantar calcaneal bone spur. Exact etiological factors are still unclear. Treatment typically consists of osteoarthritis tretment schedules and surgical techniques. External radiotherapy is another treatment option. This study is aimed to determine effectiveness and treatment outcomes of external radiotherapy in patients with PPHS.

Methods: Sixty-two patients with PPHS were analysed for radiotherapy success and other possible prognostic factors. All patients were treated with Co-60 units from parallel opposed lateral portals, to a total dose of 8 Gy. Responses to radiotherapy was assessed by visual analogue scale (VAS) of pain. Follow-up completed in December 2012 with 28 months median duration (range 22 to 35 months). Age, sex, patient number, spur settlement site, prior treatments, time interval between diagnosis and radiotherapy, pain scores (before and after radiotherapy), plantar fat-pillow thickness (PFPT; thickness of the plantar fat pad) and Böhler's angle estimations were analysed.

Results: Study included 53 female and 9 male patients with median age 57 (range 43-70). Time interval between PPHS diagnosis and radiotherapy were median 33 months (range10-60). Radiotherapy response time interval were 6 months (range 3-10 months). Responses to radiotherapy were no response in 13 patients (21%), partial response in 13 patients (21%)- pain relief below 50% and complete response - no pain in 36 patients (58%) respectively. Median PFPT of patients were 3.5 cm (range 1.20-4.50 cm). Complete response rate was statistically significant in patients whom PFPT is greater than 3.5 cm. The Böhler's angle range is about 20-40 deg. Complete response rates were higher in patients with degree of Böhler's Angle 30 and below.

Conclusions: Simplicity of treatment, lack of acute adverse effects and low cost, seem to make radiotherapy one of the safest, cheapest and also an effective treatment modality for PPHS.
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http://dx.doi.org/10.1186/2193-1801-3-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967731PMC
March 2014

A rare cause of the cough: primary small cell carcinoma of esophagus-case report.

Case Rep Med 2012 22;2012:870783. Epub 2012 Feb 22.

Department of Thoracic Surgery, Atatürk Chest Diseases and Thoracic Surgery, Training and Research Hospital, 25070 Ankara, Turkey.

Primary small cell carcinoma of the esophagus is a relatively rare malignancy. It is highly progressive and poorly prognostic in untreated conditions. In the western populations, the rate of primary small cell carcinoma in all esophageal cancer types is between 0.05% and 2.4%, while it is endemically increasing up to 7.6% in the eastern populations. Most of the cases are in extensive stage at the time of diagnosis. Surgery is the treatment of choice in limited stages, but treatment must be multimodal in primary small cell carcinoma of the esophagus. A 47-year-old woman was referred to our clinic with gradually increasing severe dry cough and slight difficulty in swallowing for 20 days. Chest X-ray graphy was normal, and computed tomography of the chest showed multiple mediastinal lymph nodes and hepatic metastases. Her endoscopic examination revealed an endoluminal vegetative mass between 20 cm and 23 cm of her esophagus. The case was reported as small cell carcinoma of the esophagus on histopathological examination. The case was assumed inoperable, and chemotherapy and radiotherapy were planned. We presented a rare cause of the cough and primary esophageal small cell carcinoma in this paper.
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http://dx.doi.org/10.1155/2012/870783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296277PMC
August 2012

Incidence and risk factors of the secondary skin infections in patients with radiodermatitis.

Eurasian J Med 2011 Dec;43(3):177-81

Department of Radiation Oncology, Regional Training and Research Hospital, Erzurum, Turkey.

Objective: The aim of this prospective study was to investigate the incidence and risk factors of secondary infected radiodermatitis in patients receiving radiotherapy and to determine isolated microorganisms' resistance profiles to different antimicrobial agents.

Materials And Methods: The study comprised 62 patients admitted to the Regional Training and Research Hospital from January 2009 to January 2010. Radiodermatitis was graded according to the National Cancer Institute's Common Toxicity Criteria version 3.0. Potential risk factors for secondary infection were recorded and evaluated by univariate and multivariate analyses.

Results: In 62 patients, grade 1, 2, 3 and 4 radiodermatitis were observed in 33 (53.2%), 11 (17.7%), 8 (12.9%) and 10 (16.2%) patients, respectively. Skin infection secondary to radiodermatitis occurred in 14 patients (infected patients), 21.4%, 21.4% and 57.2% of whom had grade 2, 3 and 4 radiodermatitis, respectively. Forty-eight patients were found to be colonized with micoorganisms (colonized patients). In the univariate analysis, concurrent endocrine therapy and radiodermatitis grade differed significantly between infected and colonized patients (p<0.05). Multivariate analyses showed that the radiodermatitis grade was an independent risk factor for the acquisition of infection (p<0.05). The microbial pathogens isolated from patients with skin infection were seven methicillin-resistant coagulase-negative Staphylococcus (MRCNS) strains, three methicillin-resistant Staphylococcus aureus (MRSA) strains, two Candida sp., one methicillin-sensitive coagulase-negative Staphylococcus (MSCNS) strain and one methicillin-sensitive S. aureus (MSSA) strain. Staphylococci strains were more resistant to beta-lactam antibiotics. No glycopeptide resistance was found.

Conclusion: The results of this study indicate that high-grade radiodermatitis leads to an increased risk for secondary infection of the skin with pathogens.
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http://dx.doi.org/10.5152/eajm.2011.34DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4261391PMC
December 2011

Pregnancy a short time after multimodal therapy for bilateral breast cancer: a case report and review of literature.

J Oncol Pharm Pract 2011 Dec 21;17(4):440-3. Epub 2010 Sep 21.

Department of Radiation Oncology, Regional Training and Research Hospital, Erzurum, Turkey.

Pregnancy occurring after multimodal therapy in a woman with breast cancer with a 1-year follow-up period is a relatively rare condition and has been defined as pregnancy-associated breast cancer. A patient can become pregnant after chemotherapy for breast cancer while she is on tamoxifen. However, the effects of tamoxifen on fetus and on the course of the pregnancy are still unknown. Here, we present a 39-year-old woman treated with chemotherapy and radiotherapy for bilateral breast cancer, and who became pregnant while taking tamoxifen.
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http://dx.doi.org/10.1177/1078155210384755DOI Listing
December 2011

Genomic instability in patients with Barrett's esophagus.

Cancer Genet Cytogenet 2010 Sep;201(2):88-93

Department of Medical Genetics, Erzurum Training and Research Hospital, Turkey.

Our study aimed to determine, by counting sister chromatid exchange (SCE) and micronucleus (MN) frequencies, whether genetic impairment and DNA damage have an effect on the pathogenesis of Barrett's esophagus (BE). This study was conducted between June 2007 and November 2008 in the Erzurum Training and Research Hospital. We analyzed SCE and MN frequencies in 30 patients with BE, and in 30 control cases. SCE was significantly increased in BE patients compared with controls (6.89 +/- 1.04 vs. 5.01+/- 0.88, P < 0.001). Similarly, MN was significantly increased in BE patients compared with controls (3.48 +/- 1.08 vs. 1.83 +/- 0.64, P < 0.001). Our data indicate that the increased SCE and MN rates in lymphocytes of patients with BE may reflect genomic instability or deficiency of DNA repair capacity.
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http://dx.doi.org/10.1016/j.cancergencyto.2010.05.003DOI Listing
September 2010

Dietary Habits, demographical, and socio-economical risk factors of the newly diagnosed gastric cancers in the Eastern Anatolia Region of Turkey: an endemic upper gastrointestinal cancer region.

Dig Dis Sci 2009 Dec;54(12):2629-33

Department of Internal Medicine, State Hospital, 25200 Erzurum, Turkey.

The Eastern Anatolia Region of Turkey is an endemic upper gastrointestinal (esophageal and gastric) cancer region, and the incidence of these cancers are still increasing in the region. We investigated demographic features, dietary habits, and some possible etiologic factors for this high prevalence. Special attention was given to the relationship between consumption of boiled yellow butter and the occurrence of gastric cancer. Age, sex, residential area, socio-economical status, educational status, vegetable and fruit consumption, alcohol and tobacco use, tea consumption, boiled butter usage, cooking and storage methods of the patients with gastric cancer and controls were investigated in East Anatolian Regional Erzurum State Hospital. Helicobacter pylori infection for gastric cancer risk was not studied. Fruit, yellow-green vegetables, boiled butter, and breads baked by animal manure consumptions and no refrigeration are found to be statistically significant etiologic factors for gastric carcinogenesis. Dietary habits might be risk factors for gastric carcinogenesis among East Anatolian population. Some regional differences in food processing and preparation also seem to play a role in gastric carcinogenesis.
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http://dx.doi.org/10.1007/s10620-008-0647-6DOI Listing
December 2009

Intraperitoneal dedifferentiated liposarcoma: a case report.

World J Gastroenterol 2008 Oct;14(38):5927-9

Erzurum State Hospital, Department of Medical Genetics, Erzurum 25240, Turkey.

Dedifferentiated liposarcoma is a variant of liposarcoma with a more aggressive course. Mutations of the p53 gene have been found in different types of soft tissue sarcoma. It is generally accepted that p53 mutations in human malignant tumors are often related to a poor prognosis. In our case, analysis of p53 gene mutation in tumor samples was performed. p53 gene mutation was observed in dedifferentiated tumor tissue samples but not in well-differentiated tumor tissue samples. It has been reported that p53 gene mutation occurs most commonly in the retroperitoneum and rarely in other anatomic locations. Herein we report a case of dedifferentiated liposarcoma located at intraperitoneum.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751908PMC
http://dx.doi.org/10.3748/wjg.14.5927DOI Listing
October 2008

Unilateral syringoma of the face associated with hyperthyroidism.

J Dermatol 2004 Oct;31(10):828-30

Department of Dermatology, Numune State Hospital, Erzurum, Turkey.

Syringomas are benign tumors derived from the intraepidermal portion of eccrine sweat ducts. They usually occur on the periobital area, but have also been found on the scalp, forehead, cheeks, axillae, abdomen, extremities, genitalia, and buttocks. We describe a patient with an unusual presentation of unilateral syringoma of the face associated with hyperthyroidism.
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http://dx.doi.org/10.1111/j.1346-8138.2004.tb00609.xDOI Listing
October 2004

Huge cystic mandibular mass.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003 Sep;96(3):253-7

Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey.

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http://dx.doi.org/10.1016/s1079-2104(03)00354-8DOI Listing
September 2003