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    The Effect of Pringle Maneuver Applied during Living Donor Hepatectomy on the Ischemia-Reperfusion Injury Observed in the Donors and Recipients
    (Mdpi, 2024) Dalda, Yasin; Akbulut, Sami; Sahin, Tevfik Tolga; Tuncer, Adem; Ogut, Zeki; Satilmis, Basri; Dalda, Ozlem
    Background and Objectives: The aim of this study is to evaluate the clinical and laboratory changes of ischemia and reperfusion injury in the remnant livers of donors with and without Pringle maneuver. Furthermore, we evaluated the recipients who have been transplanted with liver grafts from these donors. Methods and Materials: A total of 108 patients (54 living liver donors and 54 liver recipients) who underwent donor hepatectomy and recipients who living donor liver transplantation, were included in this randomized double-blind study between February 2021 and June 2021. The donors were divided into two groups: Pringle maneuver applied (n = 27) and Pringle maneuver not applied (n = 27). Similarly, recipients with implanted liver obtained from these donors were divided into two groups as the Pringle maneuver was performed (n = 27) and not performed (n = 27). Blood samples from donors and recipients were obtained on pre-operative, post-operative 0 h day (day of surgery), post-operative 1st day, post-operative 2nd day, post-operative 3rd day, post-operative 4th day, post-operative 5th day, and liver tissue was taken from the graft during the back table procedures. Liver function tests and complete blood count, coagulation tests, IL-1, IL-2, IL-6, TNF-alpha, and beta-galactosidase measurements, and histopathological findings were examined. Results: There was no statistically significant difference in the parameters of biochemical analyses for ischemia-reperfusion injury at all periods in the donors with and without the Pringle maneuver. Similarly, there was no statistically significant difference between in the recipients in who received liver grafts harvested with and without the Pringle maneuver. There was no statistically significant difference between the two recipient groups in terms of perioperative bleeding and early bile duct complications (p = 0.685). In the histopathological examinations, hepatocyte damage was significantly higher in the Pringle maneuver group (p = 0.001). Conclusions: Although the histological scoring of hepatocyte damage was found to be higher in the Pringle maneuver group, the Pringle maneuver did not augment ischemia-reperfusion injury in donors and recipients that was evaluated by clinical and laboratory analyses.
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    Effect of the COVID-19 Pandemic on the Management of Breast Cancer Patients
    (Mdpi, 2024) Dalda, Yasin; Akbulut, Sami; Kucukakcali, Zeynep; Ogut, Zeki; Dalda, Ozlem; Alan, Saadet; Isik, Burak
    Background: The COVID-19 pandemic has significantly affected breast cancer patients by causing delays in diagnosis and treatment processes. This study aims to investigate the effects of the pandemic on the treatment process and short-term outcomes of breast cancer patients. Methods: This retrospective, cross-sectional, single-center study included 414 patients who underwent surgery for breast cancer at the Inonu University General Surgery Clinic between March 2018 and June 2021. The patients were divided into two groups: pre-pandemic (Pre-COVID-19; n = 240) and pandemic (COVID-19 Era; n = 174) periods. The groups were compared in terms of demographic, clinical, and histopathological variables. Results: During the pandemic period, the use of neoadjuvant therapy (from 21.3% to 34.5%) and preoperative PET-CT imaging (from 80.4% to 90.8%) rates increased, while breast-conserving surgery (from 27.9% to 19.0%) and the presence of comorbid diseases (from 45.0% to 29.9%) decreased significantly. While there was no significant difference between the groups in terms of the time from diagnosis to surgery (25 vs. 28.5 days, p = 0.121), the time to report the pathology result after surgery decreased during the pandemic period (28 vs. 23 days, p < 0.001). There was no significant difference between the groups in terms of immunohistochemical (ER, PR, Ki-67, E-cadherin, and c-erbB2), histopathological (lymphovascular invasion, perineural invasion, comedo necrosis, modified Bloom-Richardson grade, and TNM classification), and clinical (recurrence, metastasis, and axillary lymph node metastasis) features of the tumor. The mortality rate in the Pre-COVID-19 group (7.1%) was significantly higher than in the COVID-19 Era group (2.3%) (p = 0.049). Finally, in terms of the survival analysis, a statistically significant difference was found between the Pre-COVID-19 and COVID-19 Era groups in terms of the mean follow-up duration of the patients (p = 0.044). Conclusions: The study results show that the use of neoadjuvant therapy and radical surgery preference increased in breast cancer treatment during the pandemic period, but there was no significant change in tumor biology and histopathological features. Breast-conserving surgery rates, comorbidity rates, and pathology reporting times were significantly shortened. Long-term follow-up periods of 3 and 5 years are needed to see the impact of the pandemic on breast cancer patients.
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    Gastric Cancer Surgery Before and During the COVID-19 Pandemic in Turkey: A Multicenter Comparison of Prognostic Factors, Mortality, and Survival
    (Mdpi, 2025) Dalda, Yasin; Akbulut, Sami; Ogut, Zeki; Yilmaz, Serkan; Sahin, Emrah; Dalda, Ozlem; Tuncer, Adem
    Background/Objectives: The COVID-19 pandemic disrupted global cancer care. This study compared gastric cancer surgical outcomes before and during the pandemic in Turkey. We also aimed to analyze the impact of the pandemic and factors on survival and mortality in gastric cancer patients. Materials and Methods: This retrospective, multicenter cohort study included 324 patients from three tertiary centers in Turkey who underwent gastric cancer surgery between January 2018 and December 2022. Patients were stratified into Pre-COVID-19 (n = 150) and COVID-19 Era (n = 174) groups. Comprehensive demographic, surgical, pathological, and survival data were analyzed. To identify factors independently associated with postoperative mortality, a multivariable logistic regression model was applied. For evaluating predictors of long-term survival, multivariable Cox proportional hazards regression analysis was conducted. Results: The median time from diagnosis to surgery was comparable between groups, while the time from surgery to pathology report was significantly prolonged during the pandemic (p = 0.012). Laparoscopic surgery (p = 0.040) and near-total gastrectomy (p = 0.025) were more frequently performed in the Pre-COVID-19 group. Although survival rates between groups were similar (p = 0.964), follow-up duration was significantly shorter in the COVID-19 Era (p < 0.001). Comparison between survivor and non-survivor groups showed that several variables were significantly associated with mortality, including larger tumor size (p < 0.001), greater number of metastatic lymph nodes (p < 0.001), elevated preoperative CEA (p = 0.001), CA 19-9 (p < 0.001), poor tumor differentiation (p = 0.002), signet ring cell histology (p = 0.003), lymphovascular invasion (p < 0.001), and perineural invasion (p < 0.001). Multivariable logistic regression identified total gastrectomy (OR: 2.14), T4 tumor stage (OR: 2.93), N3 nodal status (OR: 2.87), and lymphovascular invasion (OR: 2.87) as independent predictors of postoperative mortality. Cox regression analysis revealed that combined tumor location (HR: 1.73), total gastrectomy (HR: 1.56), lymphovascular invasion (HR: 2.63), T4 tumor stage (HR: 1.93), N3 nodal status (HR: 1.71), and distant metastasis (HR: 1.74) were independently associated with decreased overall survival. Conclusions: Although gastric cancer surgery continued during the COVID-19 pandemic, some delays in pathology reporting were observed; however, these did not significantly affect the timing of adjuvant therapy or patient outcomes. Importantly, pandemic timing was not identified as an independent risk factor for mortality in multivariable logistic regression analysis, nor for survival in multivariable Cox regression analysis. Instead, tumor burden and aggressiveness-specifically advanced stage, lymphovascular invasion, and total gastrectomy-remained the primary independent determinants of poor prognosis. While pandemic-related workflow delays occurred, institutional adaptability preserved oncologic outcomes.
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    Prognostic and Predictive Significance of B7-H3 and CD155 Expression in Gastric Cancer Patients
    (Mdpi, 2025) Dalda, Ozlem; Bozdag, Zehra; Akbulut, Sami; Gokce, Hasan; Dalda, Yasin; Akatli, Ayse Nur; Huz, Mustafa
    Background/Objectives: This study aimed to characterize the expression patterns of B7 homolog 3 (B7-H3) and cluster of differentiation 155 (CD155), two immune-related transmembrane glycoproteins, in resectable gastric adenocarcinoma and to elucidate their clinicopathological, prognostic, and molecular implications. Methods: The study included 112 patients who underwent gastrectomy for gastric adenocarcinoma between 2020 and 2025, along with 30 samples of normal gastric tissue obtained from sleeve gastrectomy specimens. Histological subtype, grade of differentiation, TNM stage, and invasion parameters were re-evaluated. Immunohistochemical expression of B7-H3 and CD155 was quantified for membranous, stromal and membranous/cytoplasmic staining patterns. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed on 29 tumor and 25 normal samples to confirm mRNA expression levels, with fold change >= 2 considered biologically significant upregulation and <= 0.5 considered downregulation. Machine learning models were developed to predict metastasis and mortality based on clinical and immunohistochemical features. Results: 78.5% of tumors were at an advanced stage (T3-T4), and metastasis was present in 22.3% of patients. Perineural invasion (PNI) and lymphovascular invasion (LVI) were observed in 67.9% and 88.4% of cases, respectively. Increased B7-H3 and CD155 expression were significantly associated with advanced tumor stage, metastasis, and the presence of PNI and LVI (all p < 0.05). In metastatic tumors, median membranous B7-H3, stromal B7-H3, and CD155 scores were 60, 130, and 190, respectively, compared with 20, 90, and 120 in non-metastatic tumors. A significant positive correlation was found between stromal B7-H3 and CD155 expression (r = 0.384, p < 0.001), indicating parallel upregulation. Quantitative RT-PCR confirmed significant overexpression of both genes in tumor tissues relative to normal controls. B7-H3 was upregulated in 75.9% and CD155 in 58.6% of samples, with co-upregulation in 55.2%. Fold-change levels were markedly higher in metastatic versus non-metastatic cases (B7-H3: 7.69-fold vs. 3.04-fold; CD155: 7.44-fold vs. 1.79-fold). ML analysis using the XGBoost model achieved 91.1% accuracy for metastasis prediction (F1-score 0.800). Key variables included pathological T4b stage, perineural invasion, N3b status, T4a stage, and CD155 score. The mortality model yielded 86.7% accuracy (F1-score 0.864), with metastasis, differentiation status, nodal involvement, age, lymph node ratio, and perineural invasion emerging as principal predictors. Conclusions: Combined evaluation of B7-H3 and CD155, supported by immunohistochemical staining and RT-PCR quantification of B7-H3 and CD155 mRNA expression levels, provides meaningful prognostic insights and supports their potential as dual molecular biomarkers for aggressive gastric adenocarcinoma phenotypes.