SERCAN ÖN

Dr. SERCAN ÖN

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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1 November 2024 in Current Oncology
Verified
Journal Article
Open access
PDF file
SÖSERCAN ÖN
SERCAN ÖN
BKBaris Koksal
Baris Koksal
ZAZafer ARIK
Zafer ARIK
BCBurcu Caner
Burcu Caner
DUDuygu Ercan Uzundal
Duygu Ercan Uzundal
UŞUlus Ali Şanlı
Ulus Ali Şanlı
(1) Background: Metastatic L-type sarcomas (liposarcoma and leiomyosarcoma) are rare and have a poor prognosis. Trabectedin is an effective agent that can be used after anthracyclines. This study was designed to evaluate the real-life effectiveness and safety of trabectedin. (2) Methods: A retrospective multicenter study was conducted on patients who were treated with trabectedin for metastatic L-type sarcomas at ten tertiary oncology centers between 2015 and 2023. The objective response rate (ORR), disease control rate (DCR), time to treatment failure (TTF), and overall survival (OS) were evaluated in the cohort. Cox regression analysis was used to determine prognostic factors for survival. (3) Results: A total of 98 patients (52% liposarcoma and 48% leiomyosarcoma) were included in the study. The median treatment line was three (range: 1 to 6). Thirteen patients (13.3%) underwent local treatment due to oligoprogression, and dose reduction was required in seventeen patients (17.3%) due to toxicity. The ORR and DCR were 16% and 42%, respectively. The median TTF was 3 months, and the median OS was 10 months. In univariate analysis, a significantly longer median TTF was observed in patients who underwent local treatment (p = 0.008), obtained objective responses (p < 0.001), and underwent dose reduction (p = 0.002). No statistical differences were observed according to the histologic subtype and metastatic site. In the multivariate analysis for OS, it was found that obtaining an objective response was a good prognostic factor (p = 0.003), while the presence of liver metastases was associated with a poor prognosis (p = 0.016). (4) Conclusion: Trabectedin is a suitable option for L-type sarcoma after doxorubicin-based treatments. Survival was not worse in patients who underwent dose reduction. The use of local therapies simultaneously with trabectedin can be effective.

22 February 2026 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
BKBaris Koksal
Baris Koksal
HYHasan Çağrı Yıldırım
Hasan Çağrı Yıldırım
DGDeniz Can Guven
Deniz Can Guven
FKFatih Köse
Fatih Köse
GKGörkem Köymen
Görkem Köymen
ZAZafer ARIK
Zafer ARIK
Background: Poly(ADP-ribose) polymerase (PARP) inhibitors have been established as a first-line maintenance therapy in advanced epithelial ovarian cancer (EOC) following platinum-based chemotherapy. While phase III trials have demonstrated significant progression-free survival (PFS) benefits with olaparib and niraparib, real-world data remain limited. Methods: This retrospective, multicenter real-world study included 179 patients with newly diagnosed epithelial ovarian treated with first-line maintenance olaparib or niraparib across 33 centers in Türkiye between January 2014 and March 2025. Clinical, pathological, and molecular data—including BRCA (Breast Cancer Susceptibility Gene) mutation status, origin, and variant classification—was collected. The primary endpoint was PFS, and secondary endpoints included overall survival (OS) and safety. Survival outcomes were analyzed using Kaplan–Meier methods. Results: Of 179 patients, 110 received olaparib and 69 received niraparib. BRCA mutations were present in 88.3% of patients, while 11.7% had unknown HRD status. Median follow-up was 16.5 months, and median PFS was not reached. Estimated PFS rates for the overall cohort were 91.0% at 6 months, 83.0% at 12 months, and 64.0% at 24 months. In the olaparib cohort, BRCA-mutant patients demonstrated PFS rates of 89%, 78%, 73%, and 64% at 6, 12, 18, and 24 months, respectively. In the niraparib cohort, corresponding PFS rates among BRCA-mutant patients were 87% at 6 months and 75% at 12 months. Patients harboring pathogenic BRCA variants experienced longer PFS compared with those with likely pathogenic variants. Any-grade adverse events occurred in 73.7% of patients, and grade 3–4 events in 29.6%, with hematologic toxicities predominating. Dose interruptions were more frequent with niraparib, while treatment discontinuation rates were low in both groups. No cases of myelodysplastic syndrome or acute myeloid leukemia were observed. Conclusions: In this large multicenter real-world cohort, first-line maintenance therapy with olaparib and niraparib provided durable PFS benefit in patients with advanced EOC, particularly among those with pathogenic BRCA mutations, confirming their effectiveness and manageable safety profiles in routine clinical practice.

1 July 2022 in Turkish Thoracic Journal
Verified
Journal Article
Open access
PGPınar Gürsoy
Pınar Gürsoy
BCBurcu Cakar
Burcu Cakar
SÖSERCAN ÖN
SERCAN ÖN
EGERDEM GOKER
ERDEM GOKER
DNDeniz Nart
Deniz Nart
Non-small cell lung cancer,exon 21,L861Q,erlotinib,afatinib

27 January 2026 in Cancers
Verified
Journal Article
Open access
PDF file
SÖSERCAN ÖN
SERCAN ÖN
SCSelin Cebeci
Selin Cebeci
ZTZeynep Hande Turna
Zeynep Hande Turna
ZGZeynep Gülsüm Güç
Zeynep Gülsüm Güç
DGDeniz Can Guven
Deniz Can Guven
BCBurcu Cakar
Burcu Cakar
Background/Objectives: Uveal melanoma (UM) is a subtype of melanoma that originates from the uveal layer of the eye (iris, ciliary body, choroid) and is biologically distinct from cutaneous melanoma. The real-world evidence on treatment patterns and survival outcomes, particularly from non-Western populations, remains limited. This study provides a comprehensive national overview of local and systemic management of UM across Türkiye. Methods: This multicenter retrospective cohort study, coordinated by the Turkish Oncology Group (TOG), included patients diagnosed with UM between 2012 and 2025 across 19 tertiary oncology centers. Clinical characteristics, treatment patterns, and outcomes were analyzed. Systemic therapies were subgrouped as immunotherapy or cytotoxic chemotherapy. Progression-free survival (PFS) and overall survival (OS) were assessed by the Kaplan–Meier method; prognostic factors for OS were analyzed by Cox regression. Results: A total of 113 patients were included; 89.4% presented with localized disease. During follow-up, 43.4% developed metastases, predominantly hepatic (93.5%). 47.4% of metastatic patients received liver-directed treatments; the most common treatment was radioembolization, and these treatments were associated with longer OS. Among 59 patients receiving systemic therapy, immunotherapy demonstrated higher ORR and DCR than chemotherapy across treatment lines, although small subgroup sizes limited statistical significance. Dual immune checkpoint blockade emerged as an independent favorable prognostic factor in multivariate analysis. Median OS for metastatic patients was 16 months (95% CI: 9.3–22.7). HLA-A*02:01 was positive in 29.4% of patients tested, and only three patients received tebentafusp. Conclusions: This large national cohort highlights substantial real-world heterogeneity in treatment patterns and confirms the limited efficacy of chemotherapy, the prognostic benefit of dual ICI therapy, and the potential survival advantage of liver-directed treatments in selected patients. Low HLA-A*02:01 positivity and limited access to tebentafusp remain major challenges in Türkiye. These findings provide an essential benchmark for improving treatment strategies in metastatic UM.

19 May 2025 in Journal of Chemotherapy
Verified
Journal Article
Closed access
SÖSERCAN ÖN
SERCAN ÖN
Gestational trophoblastic neoplasia (GTN) is a rare malignancy that can develop following a hydatidiform mole or a non-molar pregnancy and often presents with metastasis. Although conventional chemotherapy achieves remission in over 90% of metastatic cases some patients develop resistance. I report a 36-year-old woman with metastatic GTN after prolonged uterin bleeding and elevated β-hCG levels. Despite multiple chemotherapy regimens, including cisplatin/etoposide and EMA-CO, the patient did not achieve remission. After the failure of conventional chemotherapy, pembrolizumab, an immune checkpoint inhibitor, was introduced. This treatment resulted in a rapid decrease in β-hCG levels and a complete biochemical response. The treatment was well tolerated, only minor immune-related adverse events. After eight cycles of pembrolizumab, she remained in remission for one year. This case highlights the potential role of immunotherapy in managing chemoresistant metastatic GTN and underscores the need for further studies to establish its effectiveness in such situations.

4 April 2024 in Balkan Medical Journal
Verified
Journal Article
Open access
AGAslı Geçgel
Aslı Geçgel
SÖSERCAN ÖN
SERCAN ÖN
YÇYeliz Çiftçi
Yeliz Çiftçi
OÖOğuzcan Özkan
Oğuzcan Özkan
FAFatma Pınar Açar
Fatma Pınar Açar
BKBurçak Şaziye Karaca
Burçak Şaziye Karaca