Browsing by Author "Kostek, Osman"

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Does the Efficacy of Regorafenib Differ in Chemotherapy Refractory Metastatic Colorectal Cancer Patients Who Had Mucinous Pathology Compared To Those Who Had Non-Mucinous Pathology
(Mosby-elsevier, 2021) Ayhan, Murat; Turan, Nedim; Kostek, Osman; Tufan, Gulnihal; Ozyukseler, Deniz Tataroglu; Odabas, Hatice; Yildirim, Mahmut Emre
Purpose: To investigate the importance of mucinous histopathology on the assessment of tumor response in patients with metastatic colorectal cancer (mCRC) receiving regorafenib. Materials and method: All pa-tients diagnosed with histologically confirmed mCRC in 2 oncology centers between 2013 and 2018 were retrospectively analyzed. Among 678 patients diagnosed with mCRC, 103 patients were treated with re-gorafenib. Ninety-four of these patients who had used at least 2 cycles of regorafenib and evaluable for treatment response were included in the analysis. Histopathologically, 18 patients with mucinous adeno-carcinoma and 76 patients with nonmucinous adenocarcinoma were compared in terms of response rate and survival durations. Results : Median follow-up duration of 6 months, median age of the patients was 61 (34-77) years. While 19.1% of the patients had mucinous histology, 80.9% had nonmucinous histology. The overall response rate was significantly lower in the mucinous subgroup than the nonmucinous subgroup (5.6% vs 43.4%, respectively, P = 0.003). Similarly, both progression-free survival (3.0 vs 4.0 months, respectively, P = 0.011) and overall survival duration were shorter in the mucinous subgroup (3.0 vs 7.0 months, P = 0.016, respectively) compared with the nonmucinous subgroup. Conclusion : The histological subgroup may predict tumor response in mCRC patients receiving regorafenib. Its efficacy on nonmucinous histology had significantly more favorable than mucinous subtype. (c) 2020 Elsevier Inc. All rights reserved.
Effect of Low-Dose Acitretin Treatment on Pituitary Hormones in Psoriasis Vulgaris: a Retrospective Study
(Wolters Kluwer Medknow Publications, 2019) Karadag, Ayse Serap; Ozlu, Emin; Kostek, Osman; Bilgili, Serap Gunes; Balaharoglu, Ragip; Ertugrul, Derun Taner
Background: It has been reported that retinoids may lead to hormonal alterations. Aim: In this retrospective study, we aimed to study the effect of acitretin on pituitary hormones in psoriasis patients. Methods: Out of 50 patients intended to be studied, blood samples of 43 patients could be tested before and after 3 months of acitretin therapy (0.2 to 0.5 mg/kg/day). Results: Patients mean +/- standard deviation ages and female/male ratio were 46 +/- 17 years and 19/24, respectively. After treatment with acitretin, gamma-glutamyltransferase, alkaline phosphatase, total cholesterol and triglyceride levels increased significantly (P < 0.05). After treatment, total protein, free thyroxine (T4) levels decreased significantly (P < 0.05). No significant differences were observed between before-after acitretin treatment regarding pituitary hormone levels in psoriasis patients (P > 0.05). Limitations: The retrospective nature of the study, inability to retest blood samples of 7 patients at 3 months post treatment, low dose and short duration of acitretin treatment were limitations of this study. Conclusion: This study showed that pituitary hormones were not affected except free T4 (thyroid hormone) by acitretin treatment. Further experimental and clinical studies are needed to clarify the effect of acitretin on pituitary hormones.
Is the Prognostic Nutritional Index a Prognostic and Predictive Factor in Metastatic Non-Small Cell Lung Cancer Patients Treated With First-Line Chemotherapy
(Springer, 2020) Bozkaya, Yakup; Kostek, Osman; Sakin, Abdullah; Ozyukseler, Deniz Tataroglu; Sakalar, Teoman; Cil, Ibrahim
Purpose We aimed to assess the prognostic and predictive significance of pretreatment Onodera's prognostic nutritional index (OPNI) in metastatic non-small cell lung cancer patients (NSCLC) treated with first-line chemotherapy. Materials and methods Patients with metastatic NSCLC who attended five different medical oncology clinics between December 2008 and January 2018 were retrospectively analyzed. The optimal cut-off point for OPNI was performed by a receiver operating characteristic (ROC) curve analysis. Patients were assigned to either the low OPNI group or high OPNI group. Results A total of 333 patients were included in the study. Significant differences between the low and high OPNI groups were found regarding the rates of response to chemotherapy, sex, and hemoglobin level (p < 0.05). The patients in high OPNI group had a longer overall survival (OS) (15.3 vs. 10.6 months, p < 0.001) and progression-free survival (PFS) (6.7 vs. 5.3 months, p < 0.001) compared to the patients in low OPNI group. A multivariate analysis using Cox regression model revealed that a high OPNI score was an independent prognostic factor of OS (HR = 1.535, p = 0.002) and PFS (HR = 1.336, p = 0.014), but failed to demonstrate a statistical significance of pretreatment OPNI scores in predicting treatment response (p = 0.56). Conclusions Pretreatment OPNI is an independent prognostic factor for OS and PFS in metastatic NSCLC patients treated with first-line chemotherapy. Thus, it may be used as easily calculated and low-cost prognostic tool in the routine clinical practice in this patient group.