Tolga Köşeci

Prof. Dr. Tolga Köşeci


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

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

Representative Publications

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20 December 2024 in Medicina
Verified
Journal Article
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TKTolga Köşeci
Tolga Köşeci
MSMustafa Seyyar
Mustafa Seyyar
YCYasemin Aydınalp Camadan
Yasemin Aydınalp Camadan
HÇHalil Çelik
Halil Çelik
BMBURAK METE
BURAK METE
TCTimucin Cil
Timucin Cil
Background and Objectives: The HALP (Haemoglobin, Albumin, Lymphocyte and Platelet) score is used to predict the prognosis of different types of cancer. This study aimed to investigate the role of the HALP score in predicting pathological response in early-stage gastric cancer patients. Materials and Methods: This retrospective cohort study was conducted on 118 patients diagnosed with early-stage gastric cancer and subjected to perioperative (FLOT) treatment between 2018 and 2023. The role of the HALP score in predicting the pathological response to perioperative treatment in patients was investigated. Results: The mean age of the 118 patients included in the study was 61.3 ± 11.1 (min = 23; max = 86). In the ROC analysis, the optimum cut-off value for the HALP score in pathological response classification was found to be 28.9 (AUC = 0.710, sensitivity = 56.7%, specificity = 80%, PPV = 86.79%, NPV = 46.15%). The pathological response rate was 69% in all patients, 87% in patients with a HALP score ≥ 28.9, and 52% in patients with a HALP score < 28.9 (p < 0.001). The probability of pathological response is 6.5 times higher in patients with a HALP score ≥ 28.9. In the Fagan nomogram, when the HALP score was ≥28.9, our pathological response probability estimate (post-test response probability) was found to increase to 64.8% (Positive Likelihood Ratio = 3, Negative Likelihood Ratio = 0.53). In patients with HALP scores ≥ 28.9 and <28.9, progression rates were 16.7% and 47.8%, respectively (p < 0.001), and median survival times were 45.4 and 30.6 months (p < 0.001). Conclusions: The HALP score is a useful and easily accessible score for determining pathological responses in patients with locally advanced gastric cancer.

27 December 2024 in Cancers
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Journal Article
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STSalih Tunbekici
Salih Tunbekici
HYHaydar Çağatay Yüksel
Haydar Çağatay Yüksel
CACaner Acar
Caner Acar
GŞGökhan Şahin
Gökhan Şahin
SOSeval Orman
Seval Orman
PGPınar Gürsoy
Pınar Gürsoy
Background/Objectives: In the REGOMA trial, regorafenib demonstrated an overall survival advantage over lomustine, and it has become a recommended treatment for recurrent glioblastoma in guidelines. This study aimed to evaluate the effectiveness and safety of regorafenib as a third-line treatment for patients with recurrent glioblastoma who progressed while taking bevacizumab-based therapy. Methods: This retrospective, multicenter study in Turkey included 65 patients treated between 2021 and 2023 across 19 oncology centers. The main inclusion criteria were histologically confirmed isocitrate dehydrogenase (IDH)-wildtype glioblastoma, progression after second-line bevacizumab-based treatment, and an Eastern Cooperative Oncology Group (ECOG) performance status score of ≤2. Patients received regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle. Results: The median age of the patients was 53 years (18–67 years), with a median progression-free survival of 2.5 months (95% Confidence Interval: 2.23–2.75) and a median overall survival of 4.1 months (95% CI: 3.52–4.68). The median overall survival was improved in patients who received subsequent therapy after regorafenib treatment compared with those who did not (p = 0.022). Progression-free survival was longer in patients with ECOG 0–1 than in those with ECOG 2 (p = 0.042). The safety profile was consistent with that of the REGOMA trial, with no drug-related deaths observed. Conclusions: Regorafenib shows good efficacy and safety as a third-line treatment for recurrent glioblastoma after bevacizumab-based therapy. This study supports the use of regorafenib and emphasizes the need for further randomized studies to validate its role and optimize treatment strategies.

Verified
Journal Article
Open access
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MSMustafa Seyyar
Mustafa Seyyar
PŞPervin Can Şancı
Pervin Can Şancı
TKTolga Köşeci
Tolga Köşeci
AKAnıl Karakayalı
Anıl Karakayalı
MAMutianur Özkorkmaz Akdağ
Mutianur Özkorkmaz Akdağ
DCDevrim Cabuk
Devrim Cabuk
Objectives: Inflammation plays an important role in cancer development, and various inflammation parameters are used as potential prognostic markers. This study aimed to evaluate the effectiveness of the combined use of HALP and H index in predicting pathological response to neoadjuvant therapy in patients with HER2-positive early-stage breast cancer. Method: This retrospective cohort study was conducted on 146 HER2-positive breast cancer patients treated in two centers. To stratify patients by their predicted probability of pathological response, HALP and H index values were combined into a composite biomarker score called the combined response score (CRS). Patients were classified into three groups based on biomarker levels: 0 = low CRS (low predictive score), 1 = intermediate CRS, and 2 = high CRS (high predictive score). These groups reflect predicted response likelihood and do not represent actual pathological outcomes. Pathological response results were evaluated according to the combined response score. Pathological complete response (pCR) was defined as residual cancer burden (RCB) 0, indicating no residual invasive tumor in breast or lymph nodes. Results: The mean age of 146 early-stage breast cancer patients included in our study was 52.3 ± 11.3 (min: 29-max: 83). In the ROC analysis, the optimum cut-off value for the HALP score in pathological response classification was found to be 36 (AUC = 0.608, sensitivity = 76.29%, specificity = 44.9%, PPV = 73%, NPV = 47.89%) and 2.3 for the H index (AUC = 0.641, sensitivity = 65.98%, specificity = 51.02%, PPV = 72.73%, NPV = 43.1%). While the pathological complete response rate was 66.4% in all patients, it was 81.8% in those with a combined score of 2, 51% in those with a score of 1, and 58.6% in those with a score of 0 (p < 0.001). In the logistic regression analysis, the probability of pathological response in patients in the combined score = 2 group is 3.77 times higher than in group 0. In the Fagan nomogram, the pretest probability of pathological response is 66%, while the post-test probability for combined response score group 2 is 81.5%, and for the low-H index < 2.3 and the high-HALP ≥ 36 patient group, our estimate for pathological complete response increases to 82%. Conclusions: The HALP-H index combined score is an important predictor of pathological response in early-stage HER2-positive breast cancer patients, independent of histological type and stage. This new score may enable personalized approaches in treatment planning.

Verified
Journal Article
Open access
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TKTolga Köşeci
Tolga Köşeci
MSMustafa Seyyar
Mustafa Seyyar
MKMehmet Mutlu KIDI
Mehmet Mutlu KIDI
SBSedat Biter
Sedat Biter
KEKadir Eser
Kadir Eser
TCTimucin Cil
Timucin Cil
Background/Objectives: Renal cell carcinoma (RCC) accounts for 2–3% of all cancers, with approximately 25% of patients being detected at the metastatic stage. This study aimed to determine the prognostic significance of co-evaluating two risk parameters: one, the HALP score based on haemoglobin, albumin, lymphocyte, and platelet counts, and the other, albumin-to-alkaline phosphatase ratio (AAPR) in patients with metastatic RCC treated with targeted therapy. Methods: This retrospective cohort study included 147 patients with metastatic RCC. The HALP score and AAPR values were calculated from pre-treatment blood test results, and followingly, the cut-off value was determined by using ROC analysis. Patients were categorised into three groups with a low, moderate or high combined risk score based on this cut-off value. The effect of these risk groups on survival was evaluated. Results: The mean age of patients was 64.1 ± 11.9. The median follow-up time was 38.3 months, and the mortality rate was 53.7% in all groups. Kaplan–Meier survival analysis showed a statistically significant difference between the combined scores of the risk groups: the median survival time was 51.6 months in the low-risk group, 20.7 months in the medium-risk group, and 10.4 months in the high-risk group (p < 0.001), with 5-year survival rates being 38.8% in the low-risk group, 30% in the intermediate-risk group, and 19% in the high-risk group. When compared to the low-risk group, Cox regression analysis revealed that the mortality risk, i.e., HR (hazard ratio), was 2.42 times higher in the intermediate-risk group and 3.76 times higher in the high-risk group. A nephrectomy operation decreased the mortality risk (HR = 0.24) by 4.16 times. Conclusions: This new combined risk scoring, obtained from co-evaluating the HALP score and AAPR, was found to be an independent prognostic factor in metastatic RCC patients. This combined risk scoring is expected to help clinicians in treatment decisions.

18 May 2026 in Medicina
Verified
Journal Article
Open access
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MSMustafa Seyyar
Mustafa Seyyar
PŞPervin Can Şancı
Pervin Can Şancı
ASAbdullah Sakin
Abdullah Sakin
ABAyberk Bayramgil
Ayberk Bayramgil
ÖKÖzgecan Dülgar Kaya
Özgecan Dülgar Kaya
UKUmut Kefeli
Umut Kefeli
Background and Objectives: Perioperative fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) is the standard of care for resectable gastric and gastroesophageal junction adenocarcinoma; however, up to 50% of patients develop metastatic recurrence. These patients have prior exposure to platinum and taxane agents, and optimal first-line treatment in the metastatic setting remains undefined. This study aimed to characterize real-world treatment patterns and outcomes in patients progressing after perioperative FLOT, focusing on relapse timing and HER2 status. Materials and Methods: This retrospective, multicenter cohort study included 296 patients from 31 centers across Türkiye, stratified into early relapse (≤6 months, n = 114) and late relapse (>6 months, n = 182) groups. Survival analyses were performed using the Kaplan-Meier method and Cox proportional hazards regression. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Results: Median PFS and OS for the entire cohort were 6 and 9 months, respectively. Early relapsers had significantly shorter median PFS (4 vs. 6 months, p = 0.029) and OS (8 vs. 12 months, p = 0.047); however, early relapse timing did not retain independent prognostic significance on multivariable analysis. No significant difference in PFS or OS was observed between cytotoxic chemotherapy regimens in either relapse group. HER2 positivity was the only independent predictor of improved PFS on multivariable Cox analysis (HR 0.48, 95% CI 0.29–0.81; p = 0.006). In the late relapse group, trastuzumab-based chemotherapy achieved a median PFS of 14 months and OS of 18 months, significantly superior to all cytotoxic regimens (PFS p = 0.007; OS p = 0.029). Conclusions: In patients progressing after perioperative FLOT, cytotoxic chemotherapy regimen selection did not demonstrate a statistically significant survival difference in this retrospective cohort, regardless of relapse timing. HER2 positivity is the dominant predictive biomarker, and trastuzumab-based therapy suggests a potential survival benefit that warrants prospective validation. Comprehensive biomarker profiling at metastatic diagnosis and prospective trials designed for this post-FLOT population are needed to establish evidence-based treatment standards.

17 June 2026 in Current Oncology
Verified
Journal Article
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MSMustafa Seyyar
Mustafa Seyyar
AKAli Kalem
Ali Kalem
MSMürsel Sali
Mürsel Sali
BKBerkan Karabuğa
Berkan Karabuğa
TSTaha Koray Sahin
Taha Koray Sahin
DCDevrim Cabuk
Devrim Cabuk
Germline BRCA1/2-mutated (gBRCAm) hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancer (MBC) is a biologically distinct subset in which the efficacy of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors remains incompletely characterized. We evaluated real-world outcomes and prognostic factors in a multicenter retrospective Turkish cohort treated with a CDK4/6 inhibitor plus endocrine therapy (June 2020–September 2025). Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan–Meier and Cox methods. Among 121 patients, 30 (24.8%) had BRCA1, 88 (72.7%) had BRCA2, and three (2.5%) had dual mutations; 66.9% received first-line therapy, with ribociclib in 69.4% and palbociclib in 29.8%. Objective response rate was 69.4% and the clinical benefit rate was 82.6%. Median PFS was 17.0 months and OS 47.0 months. PFS was numerically longer in BRCA1 than in BRCA2 carriers (25.0 vs. 14.0 months), although the difference was not statistically significant in the pairwise comparison (HR 1.50, 95% CI 0.88–2.56; log-rank p = 0.135); the dual BRCA1/2 subgroup (n = 3) had the poorest outcomes and was assessed descriptively. OS did not differ significantly between BRCA1 and BRCA2 carriers (57.0 vs. 49.0 months; log-rank p = 0.520). PFS did not differ between ribociclib and palbociclib (p = 0.192); OS favored ribociclib at borderline significance (p = 0.050), but this was not confirmed in Cox regression. In multivariable analysis, ECOG ≥ 1 (HR 1.85; p = 0.010) and fulvestrant-based therapy (HR 1.74; p = 0.041) predicted shorter PFS; fulvestrant also predicted worse OS (HR 2.39; p = 0.008). CDK4/6 inhibitor-based therapy shows meaningful activity in gBRCAm HR+/HER2- MBC; the numerically poorer outcomes observed in BRCA2 carriers are hypothesis-generating and warrant validation in larger cohorts.