Tıp Fakültesi / Faculty of Medicine

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Author: search.filters.author.Onal, C.search.filters.applied.f.publicationcategory: search.filters.publicationcategory.Makale - Uluslararası Hakemli Dergi

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    The Feasibility of Prostate-Specific Membrane Antigen Positron Emission Tomography(PSMA PET/CT)-Guided Radiotherapy in Oligometastatic Prostate Cancer Patients
    (2018) Guler, O. C.; Engels, B.; Onal, C.; Everaert, H.; Van den Begin, R.; Gevaert, T.; de Ridder, M.; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0001-9108-610X; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0003-3633-6203; https://orcid.org/0000-0003-4556-5681; https://orcid.org/0000-0003-4433-8807; 28795303; AAC-5654-2020; HOC-5611-2023; B-1285-2018; F-3248-2016; F-4794-2013
    To investigate the efficacy and toxicity of 68Ga-PSMA-HBED-CC (Ga-68-PSMA) PET-CT-guided RT in the treatment of oligometastatic prostate cancer retrospectively. A total of 23 prostate cancer patients with biochemical relapse, of which 13 were castration sensitive (CS) and 10 castration resistant (CR), were treated with intensity-modulated and image-guided RT (IMRT-IGRT) on 3 metastases detected by Ga-68 PSMA PET-CT. Androgen deprivation therapy was continued in CR patients. A total of 38 metastases were treated. The involved sites were pelvic bone (n = 16), pelvic lymph nodes (n = 11), paraaortic lymph nodes (n = 6), ribs (n = 3) and vertebral body (n = 2). The median PSA prior to RT was 1.1 ng/mL (range 0.1-29.0 ng/mL). A median dose of 43.5 Gy (range 30-64 Gy) was delivered by IMRT-IGRT in 12-27 fractions. At a median follow-up of 7 months (range 2-17 months), 19 patients (83%) were in remission. Four patients (17%) developed distant recurrences. The actuarial 1-year LC, PFS and OS rates were 100, 51 (95% CI 8-83%) and 100%. Univariate analysis demonstrated a statistically significantly better PFS in CS patients as compared to CR patients (1-year PFS 67 vs. 0%, p < 0.01). One patient experienced grade 2 acute gastrointestinal toxicity. Grade 3 or more toxicity events were not observed. By providing optimal LC, low toxicity and a promising PFS in CS patients, the current retrospective study illustrated that Ga-68 PSMA PET-CT-guided RT may be an attractive treatment strategy in patients with oligometastatic prostate cancer. Validation by randomized trials is eagerly awaited.
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    The Role of Preoperative Routine Computed Tomography Scanning in The Estimation of High-Risk Factors in Endometrial Cancers
    (2018) Coban, G.; Erbay, G.; Kose, F.; Alemdaroglu, S.; Onal, C.; Celik, H.; https://orcid.org/0000-0002-3285-5519; https://orcid.org/0000-0002-1706-8680; https://orcid.org/0000-0002-0156-5973; https://orcid.org/0000-0003-4335-6659; https://orcid.org/0000-0002-2742-9021; AAI-9974-2021; AAK-5370-2021; G-4827-2016; AAI-8400-2021; HOC-5611-2023; AAL-1923-2021
    Objective: To examine the role of preoperative computed tomography (CT) in estimation of the high-risk factors in endometrial cancer cases. Materials and Methods: The data from 161 cases who were diagnosed with endometrioid adenocarcinoma with endometrial biopsy, and staged surgically were retrospectively analyzed. The diagnostic performance of a whole abdominal CT scan in terms of tumor diameter, myometrial invasion, cervical, adnexal, omental involvement, as well as pelvic para-aortic nodal involvement was examined. In addition, extra-uterine and extra-nodal incidental signs were identified. Results: The accuracy rate of preoperative CT scanning was found to be 42%, 78%, 80%, 95%, 97%, 88%, 89%, and 88% for tumor diameter, myometrial invasion, cervical, adnexal, and omental involvement, as well as pelvic para-aortic nodal involvement, respectively. Extra-uterine and extra-nodal incidental signs were identified in 18% of the cases. Incidental findings entailed a modification of management only in one case (0.62%). Conclusion: Preoperative CT scan findings do not present an alternative to intraoperative frozen section analysis or surgical staging. However, based on the findings from the preoperative CT scan, accuracy of predictions about which patients require more complex procedures (lymphadenectomy) can be improved, and therefore preoperative CT scanning may prove useful in more effective use of operating rooms.
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    The impact of air pockets around the vaginal cylinder on vaginal vault brachytherapy
    (2015) Onal, C.; Guler, O.C.; Dolek, Y.; 25562767
    Objective: To evaluate the incidence, size and predisposing factors for air pockets around the vaginal cylinder and their dosimetric effect on the vaginal mucosa. Methods: We investigated 174 patients with endometrial carcinoma treated with external radiotherapy (RT) and brachytherapy (BRT) (101 patients, 58%) or BRT alone (73 patients, 42%). The quantity, volume and dosimetric impact of the air pockets surrounding the vaginal cylinder were quantified. The proportions of patients with or without air pockets during application were stratified according to menopausal status, treatment modality and interval between surgery and RT. Results: Air pockets around the vaginal cylinder were seen in 75 patients (43%), while 99 patients (57%) had no air pockets. Only 11 patients (6.3%) received less than the prescribed dose (average 93.9% of prescribed dose; range, 79.0-99.2%). Air pockets were significantly fewer in pre-menopausal patients or in patients treated with the combination of external RT and BRT than in postmenopausal patients or patients treated with BRT alone. A significant correlation existed between the mucosal displacement of the air gap and the ratio of the measured dose at the surface of the air gap and prescribed dose (Pearson r = -0.775; p < 0.001). Conclusion: Air pockets were still a frequent problem during vaginal vault BRT, especially in post-menopausal patients or in patients treated with BRT alone, which may potentially cause dose reductions at the vaginal mucosa. Advances in knowledge: Air pockets around the vaginal cylinder remain a significant problem, which may potentially cause dose reduction in the target volume.