Browsing by Author "Olmezoglu, A"
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Item Predictive value of quantitative metabolic tumor volume and metabolic index analysis in lung cancer stereotactic radiotherapy with F-18 FDG PET/CTAras, F; Olmezoglu, AOBJECTIVE: The objective of this study was to investigate predictive value of quantitative metabolic tumor volume and metabolic index analysis in lung cancer stereotactic radiotherapy with F-18 FDG PET/CT. PATIENTS AND METHODS: Overall, 94 early-stage non-small cell lung cancer (NSCLC) patients who were administered stereotactic radiotherapy were included in the study. RESULTS: Most of the study patients were male (91.5%). Mean age of the patients was 68.5 +/- 9.0 years. The primary lung tumor was located centrally and peripherally in 25 (26.6%) and 69 (73.4%) of the patients, respectively. The median gross tumor volume (GTV) was 16.2 cc [interquartile range (IQR): 7.1-32.9]. Whereas all patients who had peripheral tumors survived. 17 patients with central tumors (70.8%) died during the study period (p= 0.001). Biologically effective dose (BED10) values were significantly higher in patients who had peripheral tumors compared with patients with central tumors (p= 0.001). Significantly more patients died in patients who had BED values below 100 Gy compared to patients who had BED values over 100 Gy (p= 0.001). The survival distributions for the two groups were significantly different (p < 0.001). Only GTV and Pretreatment SUVmean appeared as significant predictors of mortality. BED10 values showed a significant and strong positive correlation with total radiation dose, whereas it showed a significant strong negative correlation with number of fractions. CONCLUSIONS: The use of repeated 18F-FDG PET to assess survival early during stereotactic radiotherapy is possible in patients with early-stage non-small cell lung cancer. A decrease in GTV and pretreatment SUVmean according to F-18 FDG PET/CT uptake by the primary tumor correlates with survival.Item Practice patterns for oropharyngeal cancer in radiation oncology centers of TurkeyKarakoyun-Celik, O; Altun, M; Olmezoglu, A; Büyükpolat, MY; Ozkok, S; Akmansu, M; Cengiz, M; Onal, C; Dizman, A; Esassolak, MAims 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.