Browsing by Author "Sözen, TS"

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    The radiolabeling of [161Tb]Tb-PSMA-617 by a novel radiolabeling method and preclinical evaluation by in vitro/in vivo methods
    Uygur, E; Sezgin, C; Parlak, Y; Karatay, KB; Arikbasi, B; Avcibasi, U; Toklu, T; Barutça, S; Harmansah, C; Sözen, TS; Maus, S; Scher, H; Aras, O; Gümüser, FG; Muftuler, FZB
    Prostate cancer (PC) is the most prevalent cancer in elderly men, exhibiting a positive correlation with age. As resistance to treatment has developed, particularly in the progressive stage of the disease and in the presence of microfocal multiple bone metastases, new generation radionuclide therapies have emerged. Recently introduced for treating micrometastatic foci, Terbium-161 ([Tb-161]) has shown great promise in prostate cancer treatment. This study investigated the in vitro and in vivo cytotoxicity of Terbium-161 ([Tb-161])-radiolabeled prostate-specific membrane antigen (PSMA)-617. [Tb-161]Tb-PSMA-617 (7.4 MBq/nmol) demonstrated a radiochemical yield of 97.99 +/- 2.01% and hydrophilicity. [Tb-161]Tb-PSMA-617 was also shown to have good stability, with a radiochemical yield of over 95% up to 72 h. In vitro, [Tb-161]Tb-PSMA-617 exhibited cytotoxicity on LNCaP cells but not on PC3 cells. In vivo, scintigraphy imaging visualized the accumulation of [Tb-161]Tb-PSMA-617 in the prostate, kidneys, and bladder. The results suggest that [Tb-161]Tb-PSMA-617 can be an effective radiolabeled agent for the treatment of PSMA positive foci in prostate cancer.
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    Prognostic Significance of Surgical Margin Status and Gleason Grade at the Positive Surgical Margin in Predicting Biochemical Recurrence After Radical Prostatectomy in a Turkish Patient Cohort
    Koparal, MY; Sözen, TS; Aslan, G; Baltaci, S; Süer, E; Müezzinoglu, T; Akdogan, B; Türkeri, L
    Objective: To investigate the prognostic role of positive surgical margin (PSM) features in addition to well-defined risk factors in predicting biochemical recurrence (BCR) after radical prostatectomy. Materials and Methods: This study used the prostate cancer database from the Urooncology Association in Turkey. Clinical, surgical, pathological and follow-up data were recorded from the database. PSM features, including number, location, linear length and Gleason grade (GG) were also recorded. Kaplan-Meier survival analyses were performed to assess differences in BCR-free survival (BCR-FS). In order to identify prognostic factors affecting BCR-FS, univariate and multivariate Cox regression analyses were performed. Results: The study included 984 patients who met the eligibility criteria. The median follow-up time was 29 (minimum: 6, maximum: 210) months, and BCR was detected in 178 (18.1%) patients. BCR-FS was found to be significantly lower in patients with higher total prostate-specific antigen, higher International Society of Urological Pathology (ISUP) grade, extraprostatic extension (EPE), seminal vesicle invasion, lymphovascular invasion, lymph node involvement, PSM and GG at PSM (PSMGG) >= 4 (log-rank p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, p<0.001 and p=0.005). ISUP grade, EPE and PSM were identified as independent prognostic factors in predicting BCR-FS [Hazard ratio (HR): 1.89, p=0.035 and HR: 4.65, p<0.001, HR: 1.82, p=0.030, HR: 1.77, p=0.042, respectively]. Unlike the univariate analysis, in multivariate analysis, PSMGG did not prove to be an independent prognostic factor in predicting BCR-FS. Conclusion: PSM GG >= 4 was found to be significantly associated with shorter BCR-FS. There is a need for large, randomised prospective studies to clarify the role of PSMGG to be used in nomograms as an independent predictor to determine patients who would benefit from adjuvant radiation therapy.