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Goran Marošević

Društvene mreže:

D. Đokanović, R. Gajanin, Z. Gojković, G. Marošević, I. Sladojević, Vesna Gajanin, Olja Jović-Đokanović, L. Amidžić

Background: Various factors can affect the survival of patients with laryngeal cancer (LC). In this retrospective study, we assessed clinicopathological features, their prognostic value, and treatment modalities for patients with confirmed squamous cell LC. Methods: We collected patient data on demographics, clinicopathological characteristics, treatment patterns, and outcomes. The primary endpoints were overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and locoregional control (LRC). We assessed survival using the Kaplan–Meier method and Cox regression model analyses of potential prognostic parameters. Results: After a median follow-up of 76 months, 28 (33.3%) patients had a recurrence. The median OS was 78 months, with an event recorded in 50% of patients. The DSS median was not reached (NR) with a survival rate of 72.6%, the DFS survival rate was 66.7% with median NR, and the LRC survival rate was 72.6% with median NR. After conducting a multivariate analysis of significant variables, we found that only recurrence and lymphatic invasion had an independent effect on OS and recurrence in DSS, while subsite impacted DFS and LRC. Conclusions: Survival trends were consistent with other studies, except for OS. Recurrence, lymphatic invasion, and subsite location were significant factors that impacted patient survival.

Vesna Gajanin, Nikola Baroš, G. Marošević, Đuka Ninković-Baroš, Jagoda Balaban

Background / Aim: Hidradenitis suppurativa (HS) is a chronic inflammatory disease that most often affects apocrine gland-bearing areas of the skin. The treatment depends on the severity of the clinical presentation. The paper objective was to present new modalities in management and treatment of HS. Methods: The subjects in this research included the patients suffering from the severe form of HS, who were treated in the University Clinical Centre of the Republic of Srpska for the past three years. The effect of treatment of HS were monitored. In four patients, biologic therapy with adalimumab or adalimumab biosimilars was administered, while four patients received radiotherapy and 17 of them, were treated surgically. Depending on the type of treatment, the effects of therapy were monitored after 6-12 weeks by using clinical examination and by assessing the disease stage according to the Hurley staging. Due to a small number of subjects, especially in patients treated with biologic and radiotherapy, it was not possible to perform any statistical analysis and the results were presented by description, in tables and photographs. Results: Biologic therapy: Adalimumab was administered subcutaneously 80 mg, twice a month. After 12 weeks, in 4 patients was observed a regression of changes by 60-70 % when compared to previous skin changes. Radiotherapy: the total radiation dose was 5 Gy, distributed in 5 or 10 fractions. After 12 weeks an improvement by 60-70 % was observed. Surgical treatment: after 6-8 weeks, the patients were fully recovered. Conclusions: Application of biologic and radiotherapy after 12 weeks had similar results, ie it brought to regression of changes by 60-70 %. The best results were achieved after surgical treatment of HS.

H. Osmić, E. Đedović, G. Marošević

Based on the computed tomography (CT) images it is not possible to see all the lymph nodes that belong to the stomach. In radiotherapy, for a clinical target volume (CTV) delineation based on CT images, it is necessary to determine the appropriate margin around the corresponding blood vessels to make sure that all the required lymph nodes will be irradiated. The larger margin will certainly cover all the lymph nodes but it can also produce an increase of the received dose in the normal tissues. While a smaller margin can eventually spare the normal structures as a consequence it brings a higher risk of missing the suspected lymph nodes. The aim of this study was to analyse the radiation doses received by some organs at risk (OARs) in the case of the three-dimensional conformal radiotherapy (3DCRT) treatment of the gastric cancer, for lymph node CTV margin sizes 5 mm, 7 mm and 10 mm. The study included 40 patients undergo the external beam radiotherapy (EBRT) treatment of gastric cancer. The one-way analysis of variance (ANOVA) with repeated measures test and Friedman’s nonparametric test have been used for testing the statistical significance of differences among the examined groups. The difference between the examined groups has been considered significant if p < 0.05. The statistically significant differences in the dose contributions to the observed OARs (spinal cord, heart, small bowel and colon), among the examined CTVs, were found.

Danijela Trokić, G. Marošević, V. Simeunovic, S. Lekic, B. Babić, Z. Gojković

PURPOSE The purpose of this study was to evaluate Ki67 as a biomarker for response to concurrent chemo-radiotherapy in previously treated patients with standard chemotherapy protocols in the neoadjuvant setting (NACT). METHODS Evaluated were 33 patients treated concurrently with radiotherapy and capecitabine. All patients had residual disease after anthracycline-docetaxel based NACT, verified with imaging techniques and clinical exams. Response rate (RR) was evaluated 3 months after completion of the concurrent treatment, and was correlated to tumor immune-histochemical characteristics. Binary logical regression was used for model testing and correlation of Ki67 and RR. An Omnibus test showed the model to be statistically significant and that a set of depending variables can be used as predictors for treatment response with p=0.021. Model -2 log likelihood with Nagelkerke R Square were used to define significance of other tumor characteristics besides Ki67. RESULTS Only Ki67 showed statistically significant correlation with RR, as high Ki67 predicts that there will be no response to concurrent capecitabine - radiotherapy treatment in chemo-resistant advanced breast cancer. Other characteristics such as histological grade, estrogen or progesterone receptors, HER2 overexpression or lymphovascular or perineural invasion showed no significance. CONCLUSION High value of Ki67 is a negative predictor for response in concurrent capecitabine-radiotherapy treatment in chemo-resistant advanced breast cancer.

G. Kolarević, D. Jaroš, Bojan Pavičar, Tatjana Ignjć, A. Kostovski, G. Marošević, B. Predojević, D. Mirjanić

Introduction: Using computed tomography (CT) and treatment planning systems (TPS) in radiotherapy, due to the difference in photon beam energy on CT and linear accelerator, it is necessary to convert Hounsfield units (HU) to relative electron density (RED) values. The aim of this dosimetric study was to determine whether there is a significant effect of potential in the CT tube, field of view size (FOV), and phantom dimensions on the CT conversion curve CT-RED. The second aim is whether there are significant differences between the CT-RED obtained by the Computerized Imaging Reference Systems (CIRS) Thorax 002LFC phantom and the “reference” curve in the TPS, obtained by the CIRS 062M pelvis phantom, at the same CT conditions.Methods: Heterogeneous CIRS 062M and CIRS Thorax 002LFC phantoms were used, which anatomically and dimensionally represent the human pelvis, head, and thorax, with a set of known RED inserts. They were scanned on a CT LightSpeed GE simulator and obtained CT-RED.Results: The high voltage in the CT tube had a significant effect on the HU (t = 10.72, p < 0.001) for RED values >1.1, while FOV as a parameter did not show statistical significance for the 062M pelvis phantom. Comparing the slopes (062M pelvis and head) of the CT-RED for RED ≥ 1.1, the obtained value is t = 1.404 (p = 0.163). In the case of a 062M pelvis and a 002LFC phantom, we have seen a difference in RED values (for the same HU value) of 5 % in the RED region ≥ 1.1 (bone).Conclusion: Patients should be imaged on a CT simulator only at the potential of the CT tube on which the conversion curve was recorded. The influence of the FOV and scanned phantom dimensions is not statistically significant on the appearance of the calibration curve (RED ≥ 1.1).

D. Jaroš, G. Kolarević, A. Kostovski, M. Savanović, Dejan Ćazić, G. Marošević, Nataša Totorović, D. Mirjanić

Introduction: Gated tangential field-in-field (FIF) technique is used to lower the dose to organs at risk for breast cancer radiotherapy (RT). In this study, the authors investigated the accuracy of the delivered treatment plan with and without gating using a two-dimensional detector array for patient-specific verification purposes.Methods: In this study, a 6MV beams were used for the merged FIF RT (forward Intensity Modulated Radiation Therapy). The respiration signals for gated FIF delivery were obtained from the one-dimensional moving phantom using the real-time position management (RPM) system (Varian Medical Systems, Palo Alto, CA). RPM system used for four-dimensional computed tomography scanner light-speed, GE is based on an infrared camera to detect motion of external 6-point marker. The beams were delivered using a Clinac iX (Varian Medical Systems, Palo Alto, CA) with the multileaf collimator Millennium 120. The MapCheck2 (SunNuclear, Florida) was used for the evaluation of treatment plans. MapCheck2 was validated through a comparison with measurements from a farmer-type ion chamber. Gated beams were delivered using a maximum dose rate with varying duty cycles and analyzed the MapCheck2 data to evaluate treatment plan delivery accuracy.Results: Results of the gamma passing rate for relative and absolute dose differences for all ungated and gated beams were between 95.1% and 100%.Conclusion: Gated FIF technique can deliver an accurate dose to a detector during gated breast cancer RT. There is no significance between gated and ungated patient-specific quality assurance (PSQA); one can use ungated PSQA for verification of treatment plan delivery

Dejan Ćazić, G. Marošević

OBJECTIVE The aim of this study was to investigate adverse effects, progression free survival (PFS), one-year local control (LC) and one-year overall survival (OS) of patients with liver oligometastases treated with stereotactic body radiotherapy (SBRT), and whether there was a significant difference in these parameters in patients with primary colorectal cancer compared to other tumor localizations. PATIENTS AND METHODS Patients were simulated using four-dimensional computed tomography (4DCT). Using volumetric modulated arc therapy (VMAT) technique, SBRT was performed on 16 patients with <3 liver metastases. The prescribed dose was 60 Gy in 8 fractions (BED 105 Gy). Cone beam CT (CBCT) was used for image guidance before each fraction with online correction. RESULTS There were no adverse effects. Median PFS for all patients, patients with primary colorectal cancer, and patients with primary non-colorectal cancer was 11 months (SE 2.1), 16 months (SE 2.8), 6 months (SE 2.4), respectively. There was no significant difference in the PFS for these two observed groups (P=0.09). The one-year LC was 62.5%. Patients with primary colorectal cancer had one-year LC of 87.5%, while the group of patients with primary non-colorectal cancer had one-year LC of 37.5% (P=0.063). The total one-year OS was 87.5%. In the group of patients with primary colorectal cancer, the one-year OS was 100%, while in the group of patients with primary non-colorectal cancer, the one-year OS was 75% (P=0.317). CONCLUSION SBRT with 8 × 7.5 Gy can be safely delivered and is effective method of treating liver oligometastases.

G. Kolarević, D. Jaroš, G. Marošević, Dejan Ignjatic, D. Mirjanić

Background/Aim. The aim of the study was investigating the significant difference in: a) the dosimetric calculation of the radiotherapy treatment planning system (TPS) in relation to the values obtained by measuring on the linear accelerator (Linac), b) the accuracy of the dosimetric calculation between the calculating algorithms Anisotropic Algorithm (AAA) and AcurosXB in various tissues and photon beam energies. Methods. For End-to-End test we used the heterogeneous phantom CIRS Thorax002LFC, which anatomically represents the human torso with set of inserts known relative electron density (RED) for obtaining a CT calibration curve, comparable to the “reference” CIRS 062M phantom. For the AAA and AcurosXB algorithms and for 6 MV and 16 MV photon beams in the TPS Varian Eclipse 13.6, four 3D conformal (3DCRT), and one intensity modulated (IMRT) and volumetric modulated arc (VMAT) radiotherapy plans were made. Measurements of the absolute dose in the Thorax phantom, by PTW-Semiflex ionization chamber, were carried out on three Varian-DHX Linacs. Results . The difference between "reference" and measured CT conversion curves in the bone area is 3 %. For 476 phantom measurements, the difference between measured and TPS calculated dose of (3-6) %, we had in 30 (6.3 %) cases. According to regression analysis, the standardized Beta coefficient for relative errors, 6 MV vs 16 MV, was 0.337 (33.7 %, p < 0.001). Mean relative errors for AAA vs AcurosXB, using Mann-Whitney test, for bones were 1.56 % and 2.64 % (p = 0.004). Conclusion. The End-to-End test on Thorax002LFC phantom proved the accuracy of TPS dose calculation in relation to the one delivered to the patient by Linac. There is a significant difference for photon energies relative errors (higher values are obtained for 16 MV vs 6 MV). A statistically significant minor relative error in AAA vs. AcurosXB was found for the bone. test, heterogeneous phantom, calculating algorithms.

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