Publications by authors named "Ayse Kotek"

6 Publications

  • Page 1 of 1

Current treatment strategies in malignant pleural mesothelioma with a treatment algorithm.

Adv Respir Med 2019 ;87(5):289-297

Department of Radiation Oncology, Mehmet Ali Aydınlar Acıbadem University, School of Medicine, Istanbul, Turkey.

Malignant pleural mesothelioma (MPM) is arare disease with apoor prognosis. The main therapeutic options for MPM include surgery, chemotherapy, and radiation therapy (RT). Although multimodality therapy has been reported to improve survival, not every medically operable patient is able to undergo all recommended therapy. With improvements in surgical techniques and systemic therapies, as well as advancements in RT, there has been apotential new paradigm in the management of this disease. In this review, we discuss the current literature on MPM management and propose afunctional treatment algorithm.
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http://dx.doi.org/10.5603/ARM.2019.0051DOI Listing
April 2020

Correlation of conventional and conformal plan parameters for predicting radiation pneumonitis in patients treated with breast cancer.

J Breast Cancer 2012 Sep 28;15(3):320-8. Epub 2012 Sep 28.

Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana Research and Treatment Centre, Adana, Turkey.

Purpose: The purpose of this study is to evaluate the correlation between the conventional plan parameters and dosimetric parameters obtained from conformal radiotherapy (RT) planning, and between these parameters and radiation pneumontitis (RP) incidence.

Methods: Clinical and dosimetric data of 122 patients that were treated with mastectomy and adjuvant 3D conformal RT (39% received 2-field RT [2-FRT], and in addition, 61% received 4-field RT [4-FRT]) were retrospectively analyzed. Central lung depth (CLD), maximum lung depth (MLD), and lung length were measured by the conventional plan. Lung dose-volume histograms (DVH) were created with conformal planning, and the lung volumes receiving 5 to 50 Gy (V(5Gy) to V(50Gy)) were calculated. Minimum (D(min)), maximum (D(max)), and mean doses (D(mean)) for the ipsilateral lung and bilateral lungs were measured by DVH. Correlations between 3D dosimetric data and 2D radiographic parameters were analyzed.

Results: The conventional plan parameters did not significantly differ between 2-FRT and 4-FRT. The conformal plan D(min), D(max), and D(mean) values were higher in 4-FRT versus 2-FRT. CLD and MLD were correlated with DVH parameter V(5Gy) to V(45Gy) values for ipsilateral, as well as bilateral lungs for 2-FRT. MLD and ipsilateral D(mean) via 2-FRT planning had the strongest positive correlation (r=0.76, p<0.01). Moderate correlations existed between CLD and ipsilateral and bilateral lung V(5Gy-45Gy), and between MLD and bilateral lung V(5Gy-45Gy) values in 2-FRT. Only four patients developed symptomatic RP, 4 with 4-FRT and one with 2-FRT.

Conclusion: The conformal plan parameters were strongly correlated with dose-volume parameters for breast 2-FRT. With only 4 cases of Grade 3 RP observed, our study is limited in its ability to provide definitive guidance, however assuming that CLD is an indicator for RP, V(20Gy) could be used as a predictor for RP and for 2-FRT. A well-defined parameters are still required to predict RP in 4-FRT.
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http://dx.doi.org/10.4048/jbc.2012.15.3.320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468786PMC
September 2012

Dosimetric comparison of the field-in-field technique and tangential wedged beams for breast irradiation.

Jpn J Radiol 2012 Apr 21;30(3):218-26. Epub 2011 Dec 21.

Department of Radiation Oncology, Adana Research and Treatment Centre, Baskent University Faculty of Medicine, 01120 Adana, Turkey.

Purpose: To analyze tangential wedged beam and field-in-field (FIF) technique doses using dose-volume histograms and conformality indices for target volume and healthy tissues within the irradiated volume.

Materials And Methods: Thirty patients treated with breast-conserving surgery and postoperative whole breast radiotherapy were enrolled. Three plans were generated: a standard tangential plan with either one outer field wedge or bilateral wedges, and an FIF plan. Three indices were used: the dose homogeneity index (DHI), PTV dose improvement index (PDI(index)) and geometric conformity index (g). Also ipsilateral lung, heart and contralateral breast doses were compared for each plan.

Results: Dose homogeneity index was significantly lower for the FIF (0.117 ± 0.021) than for the single wedge (0.131 ± 0.025, p = 0.02) and double wedged plan (0.128 ± 0.025, p = 0.04), respectively. The g was significantly less in the FIF (0.70 ± 0.14) compared to the wedge plans (0.80 ± 0.17, p = 0.02 and 0.83 ± 0.16, p = 0.003). Contralateral breast doses were significantly lower in the FIF plan. The FIF plan significantly lowered MU compared to both the single wedge and bilateral wedge plans.

Conclusion: The dose distribution within the target was more homogenous, and the doses for healthy tissue were less in the FIF plan compared to the tangential wedge plans.
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http://dx.doi.org/10.1007/s11604-011-0034-7DOI Listing
April 2012

Impact of prophylactic cranial irradiation timing on brain relapse rates in patients with stage IIIB non-small-cell lung carcinoma treated with two different chemoradiotherapy regimens.

Int J Radiat Oncol Biol Phys 2012 Jul 13;83(4):1264-71. Epub 2011 Dec 13.

Baskent University Adana Medical Faculty, Department of Radiation Oncology, Kisla Saglik Yerleskesi, Adana, Turkey.

Purpose: To retrospectively assess the influence of prophylactic cranial irradiation (PCI) timing on brain relapse rates in patients treated with two different chemoradiotherapy (CRT) regimens for Stage IIIB non-small-cell lung cancer (NSCLC).

Methods And Materials: A cohort of 134 patients, with Stage IIIB NSCLC in recursive partitioning analysis Group 1, was treated with PCI (30 Gy at 2 Gy/fr) following one of two CRT regimens. Regimen 1 (n = 58) consisted of three cycles of induction chemotherapy (ICT) followed by concurrent CRT (C-CRT). Regimen 2 (n = 76) consisted of immediate C-CRT during thoracic radiotherapy.

Results: At a median follow-up of 27.6 months (range, 7.2-40.4), 65 patients were alive. Median, progression-free, and brain metastasis-free survival (BMFS) times for the whole study cohort were 23.4, 15.4, and 23.0 months, respectively. Median survival time and the 3-year survival rate for regimens 1 and 2 were 19.3 vs. 26.1 months (p = 0.001) and 14.4% vs. 34.4% (p < .001), respectively. Median time from the initiation of primary treatment to PCI was 123.2 (range, 97-161) and 63.4 (range, 55-74) days for regimens 1 and 2, respectively (p < 0.001). Overall, 11 (8.2%) patients developed brain metastasis (BM) during the follow-up period: 8 (13.8%) in regimen 1 and 3 (3.9%) in regimen 2 (p = 0.03). Only 3 (2.2%) patients developed BM at the site of first failure, and for 2 of them, it was also the sole site of recurrence. Median BMFS for regimens 1 and 2 were 17.4 (13.5-21.3) vs. 26.0 (22.9-29.1 months), respectively (p < 0.001).

Conclusion: These results suggest that in Stage IIIB NSCLC patients treated with PCI, lower BM incidence and longer survival rates result from immediate C-CRT rather than ITC-first regimens. This indicates the benefit of earlier PCI use without delay because of induction protocols.
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http://dx.doi.org/10.1016/j.ijrobp.2011.09.031DOI Listing
July 2012

Predictive value of metabolic 18FDG-PET response on outcomes in patients with locally advanced pancreatic carcinoma treated with definitive concurrent chemoradiotherapy.

BMC Gastroenterol 2011 Nov 10;11:123. Epub 2011 Nov 10.

Baskent University Adana Medical Faculty, Department of Radiation Oncology, Adana, Turkey.

Background: We aimed to study the predictive value of combined 18F-fluoro-deoxy-D-glucose positron emission tomography and computerized tomography (FDG-PET-CT), on outcomes in locally advanced pancreatic carcinoma (LAPC) patients treated with concurrent chemoradiotherapy (C-CRT).

Methods: Thirty-two unresectable LAPC patients received 50.4 Gy (1.8 Gy/fr) of RT and concurrent 5-FU followed by 4 to 6 cycles of gemcitabine consolidation. Response was evaluated by FDG-PET-CT at post-C-CRT 12-week. Patients were stratified into two groups according to the median difference between pre- and post-treatment maximum standard uptake values (SUVmax) as an indicator of response for comparative analysis.

Results: At a median follow-up of 16.1 months, 16 (50.0%) patients experienced local/regional failures, 6 of which were detected on the first follow-up FDG-PET-CT. There were no marginal or isolated regional failures. Median pre- and post-treatment SUVmax and median difference were 14.5, 3.9, and -63.7%, respectively. Median overall survival (OS), progression-free survival (PFS), and local-regional progression-free survival (LRPFS) were 14.5, 7.3, and 10.3 months, respectively. Median OS, PFS, and LRPFS for those with greater (N = 16) versus lesser (N = 16) SUVmax change were 17.0 versus 9.8 (p = 0.001), 8.4 versus 3.8 (p = 0.005), and 12.3 versus 6.9 months (p = 0.02), respectively. On multivariate analysis, SUVmax difference was predictive of OS, PFS, and LRPFS, independent of existing covariates.

Conclusions: Significantly higher OS, PFS, and LRPFS in patients with greater SUVmax difference suggest that FDG-PET-CT-based metabolic response assessment is an independent predictor of clinical outcomes in LAPC patients treated with definitive C-CRT.
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http://dx.doi.org/10.1186/1471-230X-11-123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3224773PMC
November 2011

Plasma citrulline levels predict intestinal toxicity in patients treated with pelvic radiotherapy.

Acta Oncol 2011 Nov 24;50(8):1167-74. Epub 2011 Aug 24.

Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey.

Background: Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity.

Material And Methods: Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed.

Results: Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 ± 10.1 μmol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 ± 5.9 μmol/l; p < 0.0001), treatment end (29.9 ± 8.8 μmol/l; p < 0.0001), and four months post-treatment (34.3 ± 12.1; p = 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent.

Conclusion: Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity.
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http://dx.doi.org/10.3109/0284186X.2011.584557DOI Listing
November 2011