Başak Oyan

Dr. Başak Oyan


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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29 December 2022 in Nutrition in Clinical Practice
Verified
Journal Article
Open access
DBDilşat Baş
Dilşat Baş
MAMustafa Erkin Arıbal
Mustafa Erkin Arıbal
EVErkan Vardareli
Erkan Vardareli
ÖSÖzlem Sönmez
Özlem Sönmez
BOBaşak Oyan
Başak Oyan
ASAlper Sonkaya
Alper Sonkaya
Background: The evaluation of body composition is an essential parameter for preventing obesity and sarcopenic obesity, which are prognostic factors in breast cancer. This study aims to validate the bioelectrical impedance analysis (BIA) of women who are breast cancer survivors by using the dual‐energy x‐ray absorptiometry (DXA) measurement method.Methods: This validation study included 104 women without metastasis between 32 and 72 years old (mean 47.03 ± 8.59) whose treatment was completed 6 months prior. Body composition analysis was performed sequentially using both measurements and when participants were hungry.Results: Meaningful differences were found in fat‐free mass (FFM) (BIA: 46.57 ± 5.54 kg; DXA: 41.06 ± 5.11 kg), body fat percentage (%BF) (BIA: 34.28% ± 6.24%; DXA: 43.91% ± 5.58%), body fat mass (FM) (BIA: 25.37 ± 8.84 kg; DXA: 31.24 ± 9.09 kg), and lean soft tissue mass (LSTM) (BIA: 4.42 ± 5.66 kg; DXA: 38.75 ± 4.98 kg) (P < 0.001). Powerful associations for body FM and strong associations for other parameters were seen. A constant and/or proportional error was found between the two devices within the direction of strong and solid components. Compared with DXA, the BIA measurement gives a lower estimate of %BF and FM and a higher estimate of LSTM and FFM.Conclusions: By the mathematical relationship between the two measurement methods, it seems possible to adapt the body composition parameters obtained from BIA of patients with breast cancer to DXA results. In the future, there will be a need to evaluate these two devices with more extensive studies.

3 October 2024 in Cancers
Verified
Journal Article
Open access
PDF file
EKEbru Karci
Ebru Karci
ABAhmet Bilici
Ahmet Bilici
BKBuket Bayram Kuvvet
Buket Bayram Kuvvet
MCMelisa Celayir
Melisa Celayir
NONeslihan Ozyurt
Neslihan Ozyurt
OYOzcan Yildiz
Ozcan Yildiz
Background/Objectives: Following the results of the phase 3 KEYNOTE-522 trial, the U.S. Food and Drug Administration approved pembrolizumab, a humanized IgG4 kappa monoclonal antibody, in combination with neoadjuvant chemotherapy as a new standard of care for high-risk early-stage triple-negative breast cancer (TNBC). This retrospective, multicenter study in Türkiye assessed the real-world efficacy and safety of neoadjuvant pembrolizumab combined with chemotherapy in early-stage TNBC. Methods: The study included 108 patients treated between 2021 and 2023 across 14 oncology centers. Three distinct neoadjuvant regimens incorporating pembrolizumab were administered at the discretion of the treating physicians. The primary outcomes were the pathological complete response (pCR) rate after neoadjuvant therapy and the 2-year event-free survival (EFS) and overall survival (OS) rates. Results: The observed pCR rate was 63.9%, closely mirroring the 64.8% reported in the KEYNOTE-522 trial. At the two-year mark, the EFS rate was 87.2% and the OS rate was 92.3%. Multivariable analysis identified pCR as the sole independent predictor of both EFS and OS. The safety profile was consistent with previous clinical trial data, with most adverse events being of grade 1–2 in severity. Conclusions: These findings provide valuable real-world confirmation of the efficacy and safety of neoadjuvant pembrolizumab–chemotherapy in early-stage TNBC, complementing evidence from randomized trials.

1 August 2022 in Turkish Journal of Gastroenterology
Verified
Journal Article
Open access
EAErman Aytaç
Erman Aytaç
LOLeyla ÖzEr
Leyla ÖzEr
BBBilgi Baca
Bilgi Baca
EBEmre BALIK
Emre BALIK
YKYersu Kapran
Yersu Kapran
TKTayfun KarahasanoğlU
Tayfun KarahasanoğlU
Colorectal cancer is the third most common cancer in Turkey. The current guidelines do not provide sufficient information to cover all aspects of the management of rectal cancer. Although treatment has been standardized in terms of the basic principles of neoadjuvant, surgical, and adjuvant therapy, uncertainties in the management of rectal cancer may lead to significant differences in clinical practice. In order to clarify these uncertainties, a consensus program was constructed with the participation of the physicians from the Acıbadem Mehmet Ali Aydınlar and Koç Universities. This program included the physicians from the departments of general surgery, gastroenterology, pathology, radiology, nuclear medicine, medical oncology, radiation oncology, and medical genetics. The gray zones in the management of rectal cancer were determined by reviewing the evidence-based data and current guidelines before the meeting. Topics to be discussed consisted of diagnosis, staging, surgical treatment for the primary disease, use of neoadjuvant and adjuvant treatment, management of recurrent disease, screening, follow-up, and genetic counseling. All those topics were discussed under supervision of a presenter and a chair with active participation of related physicians. The consensus text was structured by centralizing the decisions based on the existing data. Cite this article as: Aytaç E, Özer L, Baca B, et al. Optimizing the personalized care for the management of rectal cancer: A consensus statement. Turk J Gastroenterol. 2022;33(8):627-663.

1 April 2021 in European Journal of Breast Health
Verified
Journal Article
Closed access
NGNilgün Güldoğan
Nilgün Güldoğan
GIGul ESEN ICTEN
Gul ESEN ICTEN
FTFatma Tokat
Fatma Tokat
BTBurçin Tutar
Burçin Tutar
HKHalil Kara
Halil Kara
GDGökhan Demir
Gökhan Demir
Despite the high prevalence of lung cancer among other primary tumors, metastasis of this particular malignancy in the breast is very rare. We report three new cases of lung cancer with breast metastases and discuss radiological and clinical findings. Radiologically, each case displayed different characteristics. First, one of them had bilateral superficially and deeply located irregular lesions. Second, the patient presented with findings similar to inflammatory breast cancer. The third case had a circumscribed mass, resembling a benign complicated cyst. To guide clinicians for proper patient management, radiologists should be aware of the scope of typical and atypical imaging findings of metastatic involvement of the breast.

1 March 2020 in Balkan Medical Journal
Verified
Journal Article
Closed access
ADAtakan Demir
Atakan Demir
NMNil Kler Mandel
Nil Kler Mandel
SPSemra Paydas
Semra Paydas
GDGökhan Demir
Gökhan Demir
ÖEÖzlem Er
Özlem Er
GBGül Başaran
Gül Başaran
Background: The synthesis of CDK4/6 inhibitors with endocrine treatment in two series of treatment has been widely accepted as the standard for patients with estrogen receptor-positive metastatic breast cancer. In spite of this, the activity of CDK4/6 inhibitors in patients with metastatic breast cancer who have progressed despite receiving multiple lines of treatment is not well understood. Aims: To report the activity and safety of a CDK4/6 inhibitor (palbociclib) in patients in whom at least three lines of treatment for ER+ metastatic breast cancer had failed. Study Design: Multicenter retrospective observational cohort study. Methods: In this retrospective observational cohort study, we included 43 patients who received palbociclib after at least three lines of systemic treatment for ER+/HER2- metastatic breast cancer. Results: The median progression-free survival in our population was 7 months (25th-75th percentile, 4-10), and the median overall survival was 11 months (25th-75th percentile, 6-19). Although there were some adverse events, palbociclib was generally well tolerated, so dose reduction was needed for only six patients (14%). Conclusion: The efficacy of palbociclib among heavily treated hormone receptor-positive/HER2- patients with advanced breast cancer was acceptable in terms of clinical benefit, and it was generally well tolerated among this population.

7 May 2025 in Cancers
Verified
Journal Article
Open access
PDF file
HMHarun Muğlu
Harun Muğlu
KHKaan Helvacı
Kaan Helvacı
BKBahadır Köylü
Bahadır Köylü
MYMEHMET HALUK YÜCEL
MEHMET HALUK YÜCEL
OCOzde Melisa Celayir
Ozde Melisa Celayir
ABAhmet Bilici
Ahmet Bilici
Background/Objectives: Sacituzumab govitecan (SG) is an antibody–drug conjugate targeting Trop-2, approved for use in metastatic triple-negative breast cancer (mTNBC) and more recently in the hormone receptor-positive/HER2-negative (mHRPBC) subtype. While clinical trials have demonstrated its efficacy, real-world data—especially those involving both molecular subtypes—remain scarce. This multicenter, retrospective study aimed to evaluate real-world observational data describing the clinical outcomes, safety, and prognostic factors associated with SG treatment in patients with mTNBC or mHRPBC. Methods: A total of 68 patients treated with SG between 2022 and 2025 were included from multiple oncology centers in Turkey. Patients with mTNBC were required to have received at least one prior chemotherapy line, while mHRPBC patients had received at least two prior chemotherapy lines in addition to cyclin-dependent kinase 4 and 6 inhibitors (CDK 4/6) plus hormone therapy. The clinical outcomes—including the progression-free survival (PFS), overall survival (OS), and objective response rate (ORR)—were evaluated. Univariate and multivariate analyses were performed to identify factors influencing outcomes. Adverse events (AEs) were also documented and graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 5 (NCI-CTCAE v5.0). Results: The cohort included 35 (51.5%) mTNBC and 33 (48.5%) mHRPBC patients. The median PFS was 6.1 months, and the median OS was 12.5 months, with no significant differences between subtypes. The ORR was 52.9%, with a complete response observed in 10.3% of patients. A high Eastern Cooperative Oncology Group Performance Status (ECOG PS) and liver metastasis were independent predictors of poorer PFS and OS. Prior immunotherapy did not negatively impact SG’s efficacy. SG was generally well tolerated; the most common AEs were alopecia, anemia, neutropenia, and diarrhea. Treatment discontinuation due to AEs was rare (2.9%). Conclusions: SG was associated with similar clinical outcomes and tolerability in both the mTNBC and mHRPBC subtypes. Although the real-world PFS and OS outcomes mirror those seen in clinical trials, the absence of a control group means that these findings should be interpreted descriptively rather than as confirmation of treatment efficacy. Importantly, this study provides one of the first real-world datasets evaluating SG in the mHRPBC subgroup, highlighting its potential role beyond clinical trials. These results support SG as a valuable therapeutic option in heavily pretreated patients, warranting further prospective and biomarker-driven studies.