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Query: "author" (Iztok Takač) .

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1.
Identification of women with high grade histopathology results after conisation by artificial neural networks
Marko Mlinarič, Miljenko Križmarić, Iztok Takač, Alenka Repše-Fokter, 2022, original scientific article

Abstract: Background: The aim of the study was to evaluate if artificial neural networks can predict high-grade histopathology results after conisation from risk factors and their combinations in patients undergoing conisation because of pathological changes on uterine cervix. Patients and methods: We analysed 1475 patients who had conisation surgery at the University Clinic for Gynaecology and Obstetrics of University Clinical Centre Maribor from 1993-2005. The database in different datasets was arranged to deal with unbalance data and enhance classification performance. Weka open-source software was used for analysis with artificial neural networks. Last Papanicolaou smear (PAP) and risk factors for development of cervical dysplasia and carcinoma were used as input and high-grade dysplasia Yes/No as output result. 10-fold cross validation was used for defining training and holdout set for analysis. Results: Baseline classification and multiple runs of artificial neural network on various risk factors settings were performed. We achieved 84.19% correct classifications, area under the curve 0.87, kappa 0.64, F-measure 0.884 and Matthews correlation coefficient (MCC) 0.640 in model, where baseline prediction was 69.79%. Conclusions: With artificial neural networks we were able to identify more patients who developed high-grade squamous intraepithelial lesion on final histopathology result of conisation as with baseline prediction. But, characteristics of 1475 patients who had conisation in years 1993-2005 at the University Clinical Centre Maribor did not allow reliable prediction with artificial neural networks for every-day clinical practice.
Keywords: artificial neural networks, conisation, uterine cervical cancer, uterine cervical dysplasia, displazija materničnega vratu, rak materničnega vratu, konizacija, umetne nevronske mreže
Published in DiRROS: 24.07.2024; Views: 3; Downloads: 3
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Diagnostic performance of p16/Ki-67 dual immunostaining at different number of positive cells in cervical smears in women referred for colposcopy
Uršula Salobir Gajšek, Andraž Dovnik, Iztok Takač, Urška Ivanuš, Tine Jerman, Simona Šramek Zatler, Alenka Repše-Fokter, 2021, original scientific article

Abstract: . The aim of the study was to evaluate the diagnostic accuracy of p16/Ki-67 dual immunostaining (p16/ Ki-67 DS) in cervical cytology and the number of positive p16/Ki-67 cells to diagnose high grade cervical intraepithelial neoplasia (CIN2+) in colposcopy population. Subjects and methods. We performed an analysis on a subset cohort of 174 women enrolled within a large-scale randomised controlled human papillomavirus (HPV) self-sampling project organised as part of the population-based Cervical Cancer Screening Programme ZORA in Slovenia. This subset cohort of patients was invited to the colposcopy clinic, underwent p16/Ki-67 DS cervical cytology and had the number of p16/Ki-67 positive cells determined. Results. Among analysed women, 42/174 (24.1%) had histologically confirmed CIN2+. The risk for CIN2+ was increasing with the number of positive cells (p < 0.001). The sensitivity of p16/Ki-67 DS for detection of CIN2+ was 88.1%, specificity was 65.2%, positive predictive value was 44.6% and negative predictive value was 94.5%. Conclusions. Dual p16/Ki-67 immunostaining for the detection of CIN2+ has shown high sensitivity and high negative predictive value in our study, which is comparable to available published data. The number of p16/Ki-67 positive cells was significantly associated with the probability of CIN2+ detection. We observed a statistically significant and clinically relevant increase in specificity if the cut-off for a positive test was shifted from one cell to three cells.
Keywords: cervical cytology, high-grade dysplasia, p16/Ki-67 immunostaining
Published in DiRROS: 22.07.2024; Views: 40; Downloads: 5
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Long term results of follow-up after HPV self-sampling with devices Qvintip and HerSwab in women non-attending cervical screening programme
Teodora Bokan, Urška Ivanuš, Tine Jerman, Iztok Takač, Darja Arko, 2021, original scientific article

Abstract: We are presenting the results of the Slovenian human papillomaviruses (HPV) self-sampling pilot study in colposcopy population of National Cervical Cancer Screening Programme ZORA for the first time. One-year and four-year follow-up results are presented for two different self-sampling devices. Participants and methods. A total of 209 women were enrolled in the study at colposcopy clinic. Prior to the gynaecological examination, all women performed self-collected vaginal swab at the clinic; 111 using Qvintip and 98 using HerSwab self-sampling device. After self-sampling, two cervical smears were taken by a clinician; first for conventional cytology and second for HPV test. After that, all women underwent colposcopy and a cervical biopsy if needed. We compared sensitivity, specificity, and predictive values of cytology (at the cut-off atypical squamous cells of undetermined significance or more [ASC-US+]) and HPV test (on self- and clinician-taken samples) for the detection of cervical intraepithelial neoplasia grade 2 or more (CIN2+) after one and four years of follow-up. Hybrid Capture 2 (HC2) assay was used for all HPV testing. Results. The mean age of 209 women was 37.6 years and HPV positivity rate 67.0% (140/209), 36.9 years and 70.3% (78/111) in the Qvintip group and 38.4 years and 63.3% (62/98) in the HerSwab group, respectively. Overall, percent agreement between self and clinician-taken samples was 81.8% (kappa 0.534) in the Qvintip and 77.1% (kappa 0.456) in the HerSwab group. In the Qvintip group, the longitudinal sensitivity, specificity, positive and negative predictive values were 71.8%, 75.0%, 83.6%, 60.0% for cytology; 83.1%, 51.3%, 75.6% and 62.5% for HPV test of self-taken samples and 94.4%, 57.5%, 79.8% and 85.2% for HPV test on clinician-taken samples. In the HerSwab group, the corresponding results were 71.7%, 46.7%, 61.3%, 58.3% for cytology; 75.0%, 47.7%, 62.9% and 61.8% for HPV test on self-taken samples and 94.3%, 44.4%, 66.7% and 87.0% for clinician-taken samples, respectively. Conclusions. The results confirm that HPV self-sampling is not as accurate as clinician sampling when HC2 is used. All HPV tests showed a higher sensitivity in detecting CIN2+ compared to cytology. Due to non-inferior longitudinal sensitivity of HPV self-sampling compared to cytology, HPV self-sampling might be an option for non-attenders to the National Cancer Screening Programme.
Keywords: HPV self-sampling, cytology, high-grade intraepithelial lesion, screening programmes
Published in DiRROS: 19.07.2024; Views: 79; Downloads: 19
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Inquiry and computer program Onko-Online : 25 years of clinical registry for breast cancer at the University Medical Centre Maribor
Darja Arko, Iztok Takač, 2019, original scientific article

Published in DiRROS: 09.07.2024; Views: 78; Downloads: 35
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Incidence of positive peritoneal cytology in patients with endometrial carcinoma after hysteroscopy vs. dilatation and curettage
Andraž Dovnik, Bojana Crnobrnja, Branka Žegura Andrić, Iztok Takač, Maja Pakiž, 2017, original scientific article

Abstract: Background. The aim of the study was to compare the frequency of positive peritoneal washings in endometrial cancer patients after either hysteroscopy (HSC) or dilatation and curettage (D&C). Patients and methods. We performed a retrospective analysis of 227 patients who underwent either HSC (N = 144) or D&C (N = 83) and were diagnosed with endometrial carcinoma at the University Medical Centre Maribor between January 2008 and December 2014. The incidence of positive peritoneal cytology was evaluated in each group. Results. There was no overall difference in the incidence of positive peritoneal washings after HSC or D&C (HSC = 13.2%; D&C = 12.0%; p = 0.803). However, a detailed analysis of stage I disease revealed significantly higher rates of positive peritoneal washings in the HSC group (HSC = 12.8%; D&C = 3.4%; p = 0.046). Among these patients, there was no difference between both groups considering histologic type (chi-square = 0.059; p = 0.807), tumour differentiation (chi-square = 3.709; p = 0.156), the time between diagnosis and operation (t = 0.930; p = 0.357), and myometrial invasion (chi-square = 5.073; p = 0.079). Conclusions. Although the diagnostic procedure did not influence the overall incidence of positive peritoneal washings, HSC was associated with a significantly higher rate of positive peritoneal cytology in stage I endometrial carcinoma compared to D&C.
Published in DiRROS: 03.06.2024; Views: 185; Downloads: 91
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Prognostic significance of uPA/PAI-1 level, HER2 status, and traditional histologic factors for survival in node-negative breast cancer patients
Nina Fokter Dovnik, Iztok Takač, 2017, original scientific article

Abstract: Background. The association of HER2 status with urokinase plasminogen activator (uPA) and plasminogen activator inhibitor 1 (PAI-1) levels raises the question whether uPA/PAI-1 level carries additional clinically relevant prognostic information independently from HER2 status. The aim of our study was to compare the prognostic value of uPA/PAI-1 level, HER2 status, and traditional prognostic factors for survival in node-negative breast cancer patients. Patients and methods. A retrospective analysis of 858 node-negative breast cancer patients treated in Maribor University Clinical Center, Slovenia, in the years 2000-2009 was performed. Data were obtained from patient medical records. The median follow-up time was 100 months. Univariate and multivariate analyses of disease-free (DFS) and overall survival (OS) were performed using the Cox regression and the Cox proportional hazards model. Results. In univariate analysis, age, tumor size, grade, lymphovascular invasion, HER2 status and UPA/PAI-1 level were associated with DFS, and age, tumor size, grade, and uPA/PAI-1 level were associated with OS. In the multivariate model, the most important determinants of DFS were age, estrogen receptor status and uPA/PAI-1 level, and the most important factors for OS were patient age and tumor grade. The HR for death from any cause in the multivariate model was 1.98 (95% CI 0.83-4.76) for patients with high uPA and/or PAI-1 compared to patients with both values low. Conclusions. uPA/PAI-1 level clearly carries an independent prognostic value regardless of HER2 status in node-negative breast cancer and could be used in addition to HER2 and other markers to guide clinical decisions in this setting.
Published in DiRROS: 03.06.2024; Views: 140; Downloads: 95
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