Georgi Tosev

Dr. Georgi Tosev


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 July 2021 in Scientific Reports
Verified
Journal Article
Open access
PDF file
GTGeorgi Tosev
Georgi Tosev
WWWasilijiang Wahafu
Wasilijiang Wahafu
PRPhilipp Reimold
Philipp Reimold
IDIvan Damgov
Ivan Damgov
CSConstantin Schwab
Constantin Schwab
SDStefan Duensing
Stefan Duensing
There are currently five programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors approved for the treatment of locally advanced or metastatic urothelial carcinoma (UC) of the bladder. For platinum-ineligible patients, testing of tumor specimens for PD-L1 expression is required. However, scoring of PD-L1 immunohistochemistry is complex due to different antibodies used, the requirement to score expression in different cellular compartments and intratumoral heterogeneity. It can also be difficult to obtain and test longitudinal tumor samples, which would be desirable to monitor treatment responses and tumor evolution under treatment-induced selective pressure. In the present proof-of concept study, we provide evidence that PD-L1 can be detected in the urine of patients with non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Urine PD-L1 levels were significantly higher in NMIBC and MIBC patients when compared to patients with various non-malignant urological diseases. Further prospective and independent studies are required to assess the value of PD-L1 in the urine as a novel biomarker with potential for the early detection, prediction and therapeutic monitoring of patients with UC of the bladder.

11 April 2025 in European Urology Open Science
Verified
Journal Article
Open access
GTGeorgi Tosev
Georgi Tosev
IDIvan Damgov
Ivan Damgov
FKFranklin Kuehhas
Franklin Kuehhas
HBHendrik Borgmann
Hendrik Borgmann
JSJulian Struck
Julian Struck
TKTimur H. Kuru
Timur H. Kuru
Bladder neck stenosis (BNS) and vesicourethral anastomosis stenosis (VUAS) are uncommon but clinically significant complications following transurethral surgery and radical prostatectomy (RP), often presenting important clinical challenges because of high recurrence rates with standard treatments. We retrospectively evaluated the efficacy of the Optilume paclitaxel-coated balloon in managing recurrent BNS and VUAS. Sixteen patients who had undergone open or robotic RP, transurethral resection of the prostate, or GreenLight laser photoselective vaporization of the prostate were assessed. At 12 mo after BNS/VUAS surgery, the International Prostate Symptom Score (IPSS), postvoid residual volume (PVR), and freedom from repeat intervention were evaluated. All patients remained free from repeat intervention and anatomic recurrence at 1-yr follow-up. Among the 16 patients (seven with preexisting incontinence), 12-mo follow-up demonstrated stable continence with no worsening, and all patients reported high satisfaction and willingness to repeat the procedure. Significant improvements in scores were observed for IPSS (p < 0.001; n = 16) and IPSS quality of life (t = 4.75, p < 0.001; n = 16), while PVR did not change significantly (p = 0.442; n = 8). These findings suggest that the Optilume paclitaxel-coated balloon is an effective off-label treatment for recurrent BNS and VUAS as applied in two urology practices in Germany, corroborating evidence from randomized controlled trials on the treatment of anterior urethral strictures. We evaluated off-label use of the new drug-coated Optilume balloon for treatment of recurrent narrowing of the bladder neck or VA (vesicourethral anastomosis; surgical join between the bladder and urethra) in patients who had previously undergone prostate surgery. Our findings show that this treatment significantly improved urinary function assessed 1 year after the procedure and prevented the need for further surgeries.

26 August 2025 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
JSJohannes Salem
Johannes Salem
JMJuan J Menendez-Suarez
Juan J Menendez-Suarez
GTGeorgi Tosev
Georgi Tosev
HBHendrik Borgmann
Hendrik Borgmann
TKTimur Hasan Kuru
Timur Hasan Kuru
Background/Objectives: Penile urethral stricture is a therapeutically challenging condition that significantly impacts quality of life and is often managed initially with urethral dilation or internal urethrotomy. However, both techniques are associated with high recurrence rates, limited long-term efficacy, and potential adverse effects, particularly in the penile urethra. Urethroplasty remains the gold standard but is invasive and not suitable for all patients. Optilume, a paclitaxel-coated balloon, combines mechanical dilation with localized drug delivery to reduce recurrence rates and the need for re-intervention. This study evaluated its effectiveness in patients with penile urethral strictures. Methods: A retrospective, multicenter study was conducted at two German clinics. Eight male patients (mean age 59) with symptomatic penile urethral strictures underwent Optilume treatment. Symptom severity was assessed using the International Prostate Symptom Score (IPSS) and quality of life (QoL) scores before and after treatment. The primary endpoint was symptom improvement, while the secondary endpoint was the need for reintervention. Patients were followed for a median of 16.5 months. Statistical analyses included Wilcoxon signed-rank and Mann–Whitney U tests. Results: The median IPSS improved from 25.5 to 5.0 and QoL scores from 4.5 to 1.0 after treatment (p < 0.01 for both). No patients required reintervention during follow-up. The subgroup analysis showed slightly better outcomes in patients without prior interventions, although differences were not statistically significant. The stricture length did not correlate with treatment response. Conclusions: Optilume significantly reduces urinary symptoms and improves QoL in penile urethral strictures, and the absence of re-interventions during follow-up underscores its durable mid-term success. It offers a minimally invasive alternative to urethroplasty, particularly for patients seeking symptom relief with a shorter recovery time and no hospital stay or general anesthesia. These preliminary findings suggest that Optilume may be a promising minimally invasive option for selected patients. Larger, controlled studies are warranted to validate these results and refine patient selection criteria.

30 March 2024 in Diagnostics
Verified
Journal Article
Open access
PDF file
PRPhilipp Reimold
Philipp Reimold
GTGeorgi Tosev
Georgi Tosev
AKAdam Kaczorowski
Adam Kaczorowski
JFJana Friedhoff
Jana Friedhoff
CSConstantin Schwab
Constantin Schwab
SDStefan Duensing
Stefan Duensing
Background: Renal cell carcinoma (RCC) is among the most lethal urologic malignancies once metastatic. Current treatment approaches for metastatic RCC (mRCC) involve immune checkpoint inhibitors (ICIs) that target the PD-L1/PD-1 axis. High PD-L1 expression in tumor tissue has been identified as a negative prognostic factor in RCC. However, the role of PD-L1 as a liquid biomarker has not yet been fully explored. Herein, we analyze urine levels of PD-L1 in mRCC patients before and after either ICI therapy or surgical intervention, as well as in a series of patients with treatment-naïve RCC. Patients and Methods: The mid-stream urine of patients with mRCC (n = 4) or treatment-naïve RCC, i.e., prior to surgery from two centers (cohort I, n = 49: cohort II, n = 29) was analyzed for PD-L1 by ELISA. The results from cohort I were compared to a control group consisting of patients treated for non-malignant urologic diseases (n = 31). In the mRCC group, urine PD-L1 levels were measured before and after tumor nephrectomy (n = 1) or before and after ICI therapy (n = 3). Exosomal PD-L1 in the urine was analyzed in selected patients by immunoblotting. Results: A strong decrease in urine PD-L1 levels was found after tumor nephrectomy or following systemic treatment with ICIs. In patients with treatment-naïve RCC (cohort I), urine PD-L1 levels were significantly elevated in the RCC group in comparison to the control group (median 59 pg/mL vs. 25.7 pg/mL, p = 0.011). PD-L1 urine levels were found to be elevated, in particular, in low-grade RCCs in cohorts I and II. Exosomal PD-L1 was detected in the urine of a subset of patients. Conclusion: In this proof-of-concept study, we show that PD-L1 can be detected in the urine of RCC patients. Urine PD-L1 levels were found to correlate with the treatment response in mRCC patients and were significantly elevated in treatment-naïve RCC patients.

9 September 2021 in Scientific Reports
Verified
Journal Article
Open access
PDF file
GTGeorgi Tosev
Georgi Tosev
WWWasilijiang Wahafu
Wasilijiang Wahafu
PRPhilipp Reimold
Philipp Reimold
IDIvan Damgov
Ivan Damgov
CSConstantin Schwab
Constantin Schwab
SDStefan Duensing
Stefan Duensing

4 June 2026 in World Journal of Urology
Verified
Journal Article
Closed access
PDF file
GTGeorgi Tosev
Georgi Tosev
CGCornelius Geil-Bierschenk
Cornelius Geil-Bierschenk
IDIvan Damgov
Ivan Damgov
FKFranklin E. Kuehhas
Franklin E. Kuehhas
JSJohannes Salem
Johannes Salem
TKTimur H. Kuru
Timur H. Kuru