Tıp Fakültesi / Faculty of Medicine

Permanent URI for this collectionhttps://hdl.handle.net/11727/1403

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Author: search.filters.author.Guler, Ozan C.Subject: search.filters.subject.Radiotherapy

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    Treatment Outcomes of Patients with Cervical Cancer with Complete Metabolic Responses After Definitive Chemoradiotherapy
    (2014) Onal, Cem; Reyhan, Mehmet; Guler, Ozan C.; Yapar, Ali Fuat; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0001-8550-3368; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0003-1715-4180; 24562649; HOC-5611-2023; AAJ-5242-2021; AAC-5654-2020; AAI-8973-2021
    Purpose We sought to evaluate failure patterns and prognostic factors predictive of recurrences and survival in cervical cancer patients who are treated with definitive chemoradiotherapy (ChRT), who have a subsequent complete metabolic response (CMR) with (18) F-fluorodeoxyglucose positron-emission tomography (FDG-PET) after treatment. Methods The records of 152 cervical cancer patients who were treated with definitive chemoradiotherapy were evaluated. All patients underwent pre-treatment positron emission tomography (PET-CT), and post-treatment PET-CT was performed within a median of 3.9 months (range, 3.0-9.8 months) after the completion of ChRT. The prognoses of partial response/progressive disease (PR/PD) cases (30 patients, 18 %) and CMR cases (122 patients, %82) were evaluated. Univariate and multivariate analysis effecting the treatment outcome was performed in CMR cases. Results The median follow-ups for all patients and surviving patients were 28.7 (range, 3.3-78.7 months) and 33.2 months (range, 6.23-78.7 months), respectively. Four-year overall survival (OS) rate was significantly better in patients with CMR compared to patients with PR/PD (66.9 % vs. 12.4 %, p < 0.001, respectively). Patients with PR/PD had higher maximum standardized uptake value (SUVmax) of primary cervical tumor (26.4 +/- 10.1 vs. 15.9 +/- 6.3; p < 0.001) and larger tumor (6.4 cm +/- 2.3 cm vs. 5.0 cm +/- 1.4 cm; p < 0.001) compared to patients with CMR. Of the 122 patients with post-treatment CMRs, 25 (21 %) developed local, locoregional, or distant failure. In univariate analysis, tumor size a parts per thousand yen 5 cm, 'International Federation of Obstetricians and Gynecologists' (FIGO) stage a parts per thousand yenaEuro parts per thousand IIB, and pelvic and/or para-aortic lymph node metastasis were predictive of both overall survival (OS) and disease-free survival (DFS), while histology was predictive of only OS. In multivariate analysis, tumor size, stage and lymph node metastasis were predictive of OS and DFS. Conclusion Although CMR is associated with better outcomes, relapses remain problematic, especially in patients with bulky tumors (a parts per thousand yen 5 cm), extensive stage (a parts per thousand yen IIB) or pelvic and/or para-aortic lymph node metastasis. These findings could support the need for more aggressive treatment or adjuvant chemotherapy regimens.
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    Effective Resolution of Lung Cancer Related Tracheal and/or Bronchial Obstruction with External Beam Radiotherapy
    (2015) Topkan, Erkan; Yildirim, Berna Akkus; Ozdemir, Yurday; Guler, Ozan C.; Kose, Fatih; 0000-0001-6908-3412; 0000-0001-8120-7123; 0000-0002-2218-2074; 0000-0001-6661-4185; AAC-5654-2020; AAG-2213-2021; AAG-5629-2021; V-5717-2017
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    Prognostic Use of Pretreatment Hematologic Parameters in Patients Receiving Definitive Chemoradiotherapy for Cervical Cancer
    (2016) Onal, Cem; Guler, Ozan C.; Yildirim, Berna A.; 0000-0002-2742-9021; 0000-0001-6661-4185; 0000-0001-6908-3412; 27206286; D-5195-2014; V-5717-2017; AAC-5654-2020
    Objectives: The aim of this work was to evaluate the prognostic role of pretreatment neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in recipients of definitive chemoradiotherapy (ChRT) for cervical cancer. Methods: In 235 patients given definitive ChRT for histologically confirmed cervical cancer, clinical data and pretreatment complete blood cell counts were analyzed. Prognostic and therapeutic ramifications of NLR and PLR were assessed. Results: Median pretreatment NLR and PLR were 3.03 (range, 1.04-13.03) and 133.02 (range, 36.3-518.16), respectively. Both NLR and PLR correlated significantly with tumor size, lymph node metastasis, and treatment response. In addition to NLR and PLR, tumor stage, size, and nodal metastasis were identified by univariate analysis as significant predictors of overall survival (OS) and progression-free survival (PFS). By multivariate analysis, independent predictors of OS and PFS were NLR (OS: hazard ratio [HR], 3.322; 95% confidence interval [CI], 1.905-5.790; PFS: HR, 3.579; 95% CI, 2.106-6.082; both P < 0.001) and lymph node metastasis (OS: HR, 2.620; 95% CI, 1.706-4.023; PFS: HR, 2.989; 95% CI, 1.918-4.378; both P < 0.001), although patients' age (HR, 1.019; 95% CI, 1.003-1.035; P = 0.02) was also significantly predictive of OS. Conclusions: Pretreatment NLR and PLR were associated with larger tumors, lymph node metastasis, and poorer therapeutic responses to definitive ChRT. By multivariate analysis, pretreatment NLR and lymph node metastasis were found independently predictive of OS and PFS, whereas patients' age was significantly predictive of OS only. In patients with advanced cervical cancer, NLR is a potential biomarker, serving to guide systemic therapy and predict treatment outcomes.
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    Retrospective correlation of (68)ga-psma uptake with clinical parameters in prostate cancer patients undergoing definitive radiotherapy
    (2020) Onal, Cem; Torun, Nese; Oymak, Ezgi; Guler, Ozan C.; Reyhan, Mehmet; Yapar, Ali F.; 0000-0001-6908-3412; 0000-0001-8550-3368; 0000-0003-1715-4180; 0000-0002-2742-9021; 0000-0002-5597-676X; 32221791; AAC-5654-2020; AAJ-5242-2021; AAI-8973-2021; D-5195-2014; AAE-2718-2021
    Objective The aim of the study is to investigate the correlation between the intensity of prostate-specific membrane antigen (PSMA) uptake in primary tumor and clinico-pathological characteristics of non-metastatic prostate cancer patients treated with definitive radiotherapy (RT). Methods Using the clinical data of 201 prostate cancer patients who were referred for (68) Ga-PSMA-positron emission tomography (PET/CT) for staging and RT planning, we analyzed the correlations among intermediate- or high-risk disease based on Gleason score (GS), prostate-specific antigen (PSA) level, D'Amico risk group classification, and maximum standardized uptake (SUVmax) of primary tumor. Results Primary tumor was visualized via (68) Ga-PSMA-PET/CT scan in 192 patients (95.5%). The median SUVmax of primary tumor and metastatic lymph node were 13.2 (range 3.3-83.7) and 11.4 (range 3.6-64.5), respectively. A significant moderate correlation was observed between PSA level and median tumor SUVmax as measured by (68) Ga-PSMA-PET/CT (Spearman = 0.425; p < 0.001). Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher tracer uptake in primary tumor than their counterparts. The median SUVmax of primary tumor was highest in patients with GS 9. The primary tumor detection rates of (68) Ga-PSMA-PET/CT were 83%, 92%, and 99% for patients with serum PSA <= 5.0 ng/mL (14 patients, 7%), PSA 5.1-10.0 ng/mL (45 patients, 22%), and PSA > 10 ng/mL (142 patients, 71%), respectively. Conclusions We demonstrated a correlation between prostate tumor characteristics and PSMA tracer uptake. Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher SUV than their counterparts. In addition, the primary tumor detection rate was higher in patients with serum PSA > 10 ng/mL and GS > 7.