İlker Nihat Ökten

Dr. İlker Nihat Ökten

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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14 March 2020 in Current Problems in Cancer
Verified
Journal Article
Closed access
TTTugba Akin Telli
Tugba Akin Telli
İÖİlker Nihat Ökten
İlker Nihat Ökten
TTTugba Basoglu Tuylu
Tugba Basoglu Tuylu
NDNazım can Demircan
Nazım can Demircan
RARukiye Arikan
Rukiye Arikan
PYPerran Fulden Yumuk
Perran Fulden Yumuk

18 August 2022 in Heliyon
Verified
Journal Article
Open access
SKSİNAN KOCA
SİNAN KOCA
EKEsra Koca
Esra Koca
İÖİlker Nihat Ökten
İlker Nihat Ökten
FOFatma Fc. Orengül
Fatma Fc. Orengül
AOAkın Oztürk
Akın Oztürk
MGMahmut Gümüş
Mahmut Gümüş
Although cancer patients have a high risk of exposing COVID-19 and developing severe complications, they have to receive active treatment. We aimed to determine the psychological conditions of cancer patients and shed light on the establishment of early psychological intervention and intervention policies by making specific recommendations. We consecutively evaluated 385 cancer patients under treatment. Post-traumatic stress disorder (PTSD) symptoms, depression, anxiety, stress, and associated sociodemographic/clinical characteristics were investigated. In addition, we applied depression-anxiety-stress-scale-21 (DASS-21) for the mental states of patients and Impact of Event-Scale-Revised (IES-R) for the psychological effects of Covid-19. The mean age was 58 (18–88). 47.2% were psychologically distressful per DASS-21, and 39.3% were traumatic per IES-R scores. 71.9% stated the risk of getting COVID-19 was high since they had cancer, and 82% stated serious complications would develop if they had COVID-19 infection. Patients diagnosed for more than one year were more stressed, anxious, and depressive (p–value = 0.001,0.003,0.049, respectively). Singles were more stressed, depressed, and traumatized than couples (p-value = 0.001, 0.011, 0.001). In multivariate analysis, a significant correlation with being under psychiatric treatment before the pandemic was found for depression (OR: 3.743, 95 %CI: 1.790–7.827) anxiety (OR: 3.776–95 %CI: 1.945–7.332) and stress levels (OR: 4.129, 95 %CI: 1.728–9.866). Having relatives who died or received treatment for COVID-19(OR: 0.515,0.296–0.895) and being unmarried (OR: 2.445–95% CI: 1.260–4.747) predicts PTSD development. When the psychological effects of the COVID-19 pandemic are manifesting strongly, cancer patients' anxiety and exposure levels are high. It is of great importance that clinicians understand needs, recognize psychological distress, and direct them to relevant departments for supportive care.

9 March 2026 in Frontiers in Oncology
Verified
Journal Article
Open access
PDF file
İÖİlker Nihat Ökten
İlker Nihat Ökten
TBTuba Baydaş
Tuba Baydaş
Background: Neurological immune-related adverse events (N-irAEs) represent rare but potentially fatal complications of immune checkpoint inhibitor (ICI) therapy. Among these, encephalitis associated with paraneoplatic neuronal antibodies poses a major diagnostic and therapeutic challenge, as it blurs the distinction between drug-induced toxicity and tumor-driven autoimmunity. Case presentation: We report a 61-year-old male diagnosed with unresectable sarcomatoid pleural mesothelioma who was treated with first-line nivolumab plus ipilimumab. Following the third treatment cycle, the patient developed progressive hyperphagia, central sleep apnea, and autonomic dysfunction. Serum testing revealed strong positivity for anti-Ma2/Ta antibodies, while brain magnetic resonance imaging was unremarkable. Despite discontinuation of immunotherapy and treatment with high-dose corticosteroids and intravenous immunoglobulin, the patient experienced relentless neurological deterioration. Notably, follow-up positron emission tomography demonstrated complete metabolic tumor response. The patient ultimately died from progressive brainstem dysfunction. Discussion: Anti-Ma2–associated encephalitis is classically categorized as a paraneoplastic neurological syndrome mediated by cytotoxic T-cell responses against intracellular neuronal antigens. Recent evidence suggests that ICIs can unmask or accelerate latent paraneoplastic autoimmunity by amplifying pre-existing immune responses. In this context, our case is best interpreted as an ICI-triggered paraneoplastic neurological syndrome rather than a primary immune-related adverse event. Conclusion: This case highlights a fatal neurological complication occurring in parallel with complete oncologic remission, underscoring the paradox of effective cancer immunotherapy precipitating catastrophic immune-mediated neurotoxicity. Early recognition of prodromal neurological symptoms and heightened awareness of paraneoplastic syndromes in the ICI era are critical to improving patient outcomes.

13 February 2026 in BMC Cancer
Verified
Journal Article
Open access
PDF file
İÖİlker Nihat Ökten
İlker Nihat Ökten
TBTuba Baydaş
Tuba Baydaş
SKSinan Koca
Sinan Koca
MBMukaddes Feyza Baltacı
Mukaddes Feyza Baltacı
FÖFiliz Özen
Filiz Özen
OYOsman Cem Yılmaz
Osman Cem Yılmaz
Germline testing for BRCA1 and BRCA2 has become integral to the management of breast cancer, with pathogenic variants strongly influencing surgical decisio

18 May 2026 in Medicina
Verified
Journal Article
Open access
PDF file
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.

7 January 2026 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
İÖİlker Nihat Ökten
İlker Nihat Ökten
TBTuba Baydaş
Tuba Baydaş
MYMAHMUT EMRE YİLDİRİM
MAHMUT EMRE YİLDİRİM
CBCemil Bilir
Cemil Bilir
SYSuayib Yalcin
Suayib Yalcin
NKNuri Karadurmuş
Nuri Karadurmuş
Background: Metastasectomy is a cornerstone of multimodal management in metastatic colorectal cancer (mCRC), yet contemporary real-world data focusing specifically on RAS wild-type (RAS-WT) disease remain limited. We aimed to evaluate survival outcomes and prognostic factors associated with metastasectomy in patients with RAS-WT mCRC using a large national multicentre registry. Methods: This retrospective cohort study utilized data from the ONKO-KOLON Türkiye registry. A total of 1079 patients with pathologically confirmed KRAS/NRAS wild-type mCRC were identified and categorized according to receipt of metastasectomy. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method and compared with log-rank tests across multiple clinically relevant time origins, including metastatic diagnosis, initial colorectal cancer diagnosis, and time of metastasectomy. Prognostic factors within the metastasectomy cohort were assessed using univariate Cox proportional hazards models. Serum CEA and CA19-9 were analyzed after log10 transformation. Results: Among 1079 patients, 185 (17.1%) underwent metastasectomy. Patients receiving metastasectomy demonstrated significantly longer OS compared with those managed non-surgically when survival was calculated from the time of metastatic diagnosis (hazard ratio [HR] for death 0.36, 95% CI 0.27–0.47; p < 0.001), as well as improved PFS (HR for progression or death 0.39, 95% CI 0.30–0.52; p < 0.001). The survival advantage remained consistent when OS was measured from the time of initial colorectal cancer diagnosis (HR 0.37, 95% CI 0.25–0.50; p < 0.001). Median OS following metastasectomy was 43 months (95% CI 31.4–45.6). In univariate analyses within the metastasectomy cohort, higher baseline CA19-9 levels were significantly associated with inferior OS when analyzed both as a continuous variable (per log10 increase; HR 1.81, 95% CI 1.20–2.75; p = 0.005) and as a categorical variable (above vs. below threshold; HR 0.37, 95% CI 0.16–0.86; p = 0.021). Other clinicopathologic factors, including age, CEA, tumor sidedness, grade, MSI status, and metastatic burden, were not significantly associated with survival. Conclusions: In this large, real-world national cohort of RAS-WT mCRC, metastasectomy was strongly associated with prolonged survival across multiple clinically relevant time frames. Within surgically treated patients, baseline CA19-9 emerged as the most informative prognostic marker, while traditional clinicopathologic variables showed limited discriminatory value. These findings highlight the importance of careful patient selection and support further prospective studies integrating molecular and biomarker-based strategies to refine prognostication and optimize surgical decision-making in RAS-WT mCRC.