Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item Impact of adjuvant radiotherapy and mitotane on survival in localized adrenocortical carcinoma: A retrospective cohort study(Başkent Üniversitesi Tıp Fakültesi, 2025) Elmali, Aysenur; Guler, Ozan Cem; Ozyigit, Gokhan; Hurmuz, Pervin; Onal, Cem; 41399138Objectives: Adrenocortical carcinoma (ACC) is a rare, aggressive tumor with high recurrence rates after surgery. Although radiotherapy (RT) has historically been underutilized in ACC, modern RT techniques have renewed interest in its potential role for improving local control (LC). This study evaluated long-term outcomes and prognostic factors in high-risk localized ACC treated with adjuvant RT and mitotane. Methods: In this multicenter retrospective study, 23 patients with localized, high-risk ACC who underwent complete surgical resection followed by adjuvant RT between 2003 and 2023 were analyzed. All received mitotane, and 21.6% also received platinum-based chemotherapy. RT was delivered using image-guided IMRT or VMAT to a median dose of 50.4 Gy, targeting the tumor bed with or without regional lymphatics. Survival was estimated using the Kaplan-Meier method, and prognostic factors were assessed with Cox regression analyses. Results : At a median follow-up of 84.7 months, the 5-year LC, overall survival (OS), and disease-free survival (DFS) rates were 85.5%, 58.6%, and 45.6%. Locoregional recurrence occurred in two patients (8.6%), with isolated local failure in one (4.3%). Distant metastasis (DM) developed in 47.8% and was the predominant failure pattern. On univariable analysis, age > 55 years predicted worse OS and DFS, while female sex independently predicted inferior DFS. Treatment was well tolerated, with no grade >= 3 RT-related toxicities. Conclusions: Adjuvant RT achieves excellent LC with minimal toxicity in high-risk localized ACC. These exploratory findings, limited by small cohort size, retrospective design, and absence of a comparator group, warrant confirmation in larger prospective multicenter studies.Item Prevention of Radiation-Induced Retinopathy with Amifostine in Wistar Albino Rats(2015) Yildirim, Berna Akkus; Cetin, Eren; Topkan, Erkan; Ozyigit, Gokhan; Cengiz, Mustafa; Surucu, Selcuk; Usubutun, Alp; Akyol, Fadil; 0000-0001-6661-4185; 25768249; V-5717-2017Item Oligometastatic Bone Disease in Castration-Sensitive Prostate Cancer Patients Treated With Stereotactic Body Radiotherapy Using Ga-68-PSMA PET/CT TROD 09-004 Study(2021) Onal, Cem; Ozyigit, Gokhan; Akgun, Zuleyha; Atalar, Banu; Igdem, Sefik; Oymak, Ezgi; Agaoglu, Fulya; Selek, Ugur; Guler, Ozan Cem; Hurmuz, Pervin; 33661210Purpose To evaluate the outcomes of metastasis-directed treatment (MDT) using stereotactic body radiotherapy (SBRT) for bone-only oligometastasis (OM) detected with gallium prostate-specific membrane antigen (Ga-68-PSMA) PET/CT in castration-sensitive prostate cancer (PC) patients. Methods In this multi-institutional study, clinical data of 74 PC patients with 153 bone lesions who were undergoing MDT were retrospectively evaluated. Twenty-seven patients (36.5%) had synchronous, and 47 (63.5%) had metachronous OM. All patients had PC with 5 metastases or fewer detected by Ga-68-PSMA PET/CT and treated using SBRT with a median dose of 20 Gy. The prognostic factors for PC-specific survival (PCSS) and progression-free survival (PFS) were analyzed. Results The median follow-up was 27.3 months. Patients with synchronous OM were older and received higher rates of androgen deprivation therapy after SBRT compared with patients with metachronous OM. The 2-year PCSS and PFS rates were 92.0% and 72.0%, respectively. A prostate-specific antigen (PSA) decline was observed in 56 patients (75.7%), and 48 (64.9%) had a PSA response defined as at least 25% decrease of PSA after MDT. The 2-year local control rate per lesion was 95.4%. In multivariate analysis, single OM and PSA response after MDT were significant predictors for better PCSS and PFS. In-field recurrence was observed in 4 patients (6.5%) with 10 lesions at a median of 13.1 months after MDT completion. No serious late toxicity was observed. Conclusions We demonstrated that SBRT is an efficient and well-tolerated treatment option for PC patients with 5 bone-only oligometastases or fewer detected with Ga-68-PSMA PET/CT.Item Integration of 68Ga-PSMA-PET/CT in Radiotherapy Planning for Prostate Cancer Patients(2019) Onal, Cem; Torun, Nese; Akyol, Fadil; Guler, Ozan Cem; Hurmuz, Pervin; Yildirim, Berna Akkus; Caglar, Meltem; Reyhan, Mehmet; Ozyigit, Gokhan; 0000-0001-6908-3412; 31283600Purpose To assess the role of (68)Gallium-labeled-prostate-specific membrane antigen PET/CT (Ga-68-PSMA-PET/CT) in risk group definition and radiotherapy planning in the initially planned definitive radiotherapy (RT) for prostate cancer patients. Methods The clinical data of 191 prostate cancer patients treated with definitive intensity-modulated RT were retrospectively analyzed. All patients were initially staged with thoracoabdominal CT and bone scintigraphy, and the second staging was performed using Ga-68-PSMA-PET/CT. Both stages were evaluated for the decision making of RT and any change in RT target volumes. Results After staging with Ga-68-PSMA-PET/CT, 26 patients (13.6%) had risk group changes, 16 patients (8.4%) had an increase in risk group, and 10 patients (5.2%) had a decrease in risk group. Down-staging occurred in 22 patients (11.5%), and upstaging was observed in 30 patients (15.7%). A total of 26 patients (13.6%) had nodal stage changes. After the Ga-68-PSMA-PET/CT scans, the number of metastatic patient increased to 17 (8.9%), with 4 of them moving from oligo- to polymetastatic disease. An additional irradiation of pelvic lymphatics and metastatic site was performed in 13 patients (6.8%) and 6 patients (3.2%), respectively. The RT was aborted in 4 patients (2.1%) because of parenchymal or distant site metastasis observed in the Ga-68-PSMA-PET/CT. Conclusions We found that Ga-68-PSMA-PET/CT causes considerable migration in stage, risk group, and RT field arrangements, especially in high-risk patients regardless of the GS and baseline prostate-specific antigen values alone. Ga-68-PSMA-PET/CT seems to have a great influence on RT decision making in prostate cancer patients.