Purpose: To assess the role of ⁶⁸Gallium-labeled-prostate-specific membrane antigen PET/CT (⁶⁸Ga-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 ⁶⁸Ga-PSMA-PET/CT. Both stages were evaluated for the decision making of RT and any change in RT target volumes. Results: After staging with ⁶⁸Ga-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 ⁶⁸Ga-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 ⁶⁸Ga-PSMA-PET/CT. Conclusions: We found that ⁶⁸Ga-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. ⁶⁸Ga-PSMA-PET/CT seems to have a great influence on RT decision making in prostate cancer patients.

Chordomas are uncommon neoplasms and there is still controversy regarding establishment of diagnosis and management. The aim of this study was to evaluate efficacy and toxicity of fractionated stereotactic radiosurgery (FSRS) in skull base chordomas. There were 4 female (36%) and 7 male (64%) patients. FSRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA). The median tumor volume was 14.7 cc (range, 3.9–40.5 cc). The median marginal tumor dose was 30 Gy (range, 20–36 Gy) in a median 5 fractions (range, 3–5 fractions). The median follow-up time was 42 months (range, 17–63 months). At the time of analysis, 10 (91%) patients were alive and 1 (9%) had died due to tumor progression. Of 10 patients, 8 (73%) had stable disease and the remaining 2 (18%) had progressive disease. The actuarial overall survival (OS) after FSRS was 91% at two-years. Two patients developed radiation-induced brain necrosis as a complication in the 8^th and 28^th months of follow-up, respectively. Our results with robotic FSRS in skull base chordomas are promising for selected patients. However, due to the slow growth pattern of skull base chordomas, a longer follow-up is required to determine exact treatment results and late morbidity.

Purpose: Stereotactic body radiotherapy (SBRT) is an effective treatment option for patients with early-stage non-small cell lung cancer (NSCLC). In this study, we evaluated the treatment results using two different SBRT techniques and the effect of beam-on time (BOT) on treatment outcomes. Methods: Between July 2007 and January 2018, 142 patients underwent SBRT for primary NSCLC. We have delivered SBRT using either respiratory tracking system (RTS) or internal-target-volume (ITV)-based motion management techniques. The effect of age, tumor size, pretreatment tumor SUVmax value, presence of tissue diagnosis, histopathological subtype, operability status, tumor location, motion management technique, BED10 value, BOT on overall survival (OS), loco-regional control (LRC), event-free survival (EFS) and primary tumor control (PTC) were evaluated. Results: Median age of the patients was 70 years (range, 39–91 years). Most of the patients were inoperable (90%) at the time of SBRT. Median BED10 value was 112.5 Gy. With a median follow-up of 25 months, PTC was achieved in 91.5% of the patients. Two-year estimated OS, LRC, PTC and EFS rates were 68, 63, 63 and 53%, respectively. For the entire group, OS was associated with BOT (P = 0.027), and EFS was associated with BOT (P = 0.027) and tumor size (P = 0.015). For RTS group, OS was associated with age (P = 0.016), EFS with BOT (P = 0.05) and tumor size (P = 0.024), LRC with BOT (P = 0.008) and PTC with BOT (P = 0.028). The treatment was well tolerated in general. Conclusion: SBRT is an effective and safe treatment with high OS, LRC, EFS and PTC rates in patients with primary NSCLC. Protracted BOT might deteriorate SBRT outcomes.

Purpose: The Expanded Prostate Cancer Index Composite (EPIC) is a symptom scale that measures health‐related quality of life (HRQoL) in prostate cancer (PCa) patients. This scale is translated into different languages and used in daily practice. This study aimed to translate the EPIC scale into Turkish and provide Turkish validation by conducting validity and reliability analyses.Methods: Patients with biopsy‐proven PCa who received definitive or postoperative radiotherapy (RT) at our department were included. All participants were evaluated using the Turkish EPIC, The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC‐QLQ) C30, and EORTC‐QLQ PR25 questionnaires at five different time points. First, the original English version of the EPIC was translated into Turkish, and then, two reliability and five validity analyses were performed.Results: One hundred‐five patients were included in the study. In the reliability analyses, Cronbach's alpha values of the whole scale were measured at 0.866, and the main scales' Cronbach's alpha values were measured between 0.654 and 0.969. In the test‐retest analysis, the correlation values of the main scales were measured between 0.413 and 0.861. The pilot study with 20 patients was completed, thus providing face validity. Sensitivity to change analysis, interscale correlation, criterion validity, and explanatory factor analyses were performed, and results proving the scale's validity were obtained in all analyses.Conclusion: The Turkish EPIC scale is applicable for patients in the Turkish population diagnosed with PCa who received either definitive or postoperative RT.