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Öğe Bevacuzimab May Be Less Effective in Obese Metastatic Colorectal Cancer Patients(Springer, 2019) Artac, Mehmet; Korkmaz, Levent; Coskun, Hasan Senol; Dane, Faysal; Karabulut, Bulent; Karaagac, Mustafa; Cabuk, DevrimPurposeThe purpose of this study was to investigate whether obesity affects survival in metastatic colorectal cancer (mCRC) patients treated with bevacizumab combined with chemotherapy.MethodsA total of 563 patients with mCRC who had received first-line chemotherapy in combination with bevacizumab were studied. Patients were grouped as obese (BMI levels >30) or non-obese (BMI levels <30). Progression-free survival (PFS) and overall survival (OS) were analyzed. Primary tumor location was also investigated in terms of PFS and OS.ResultsThe median age of the patients was 59years. The non-obese group had longer PFS than the obese group (P=0.030). The 2-year survival rate of the non-obese group was also significantly higher (P=0.036). The median PFS of non-obese patients was significantly longer in Kras wild-type patients (10.1 vs. 8.1months, P=0.010). Among patients with left-sided primary tumor location, median PFS and OS were significantly higher in the non-obese group (PFS non-obese, 11.5months; obese, 8.8months; P=0.002) (OS non-obese, 29.4months; obese, 21.4months; P=0.026).ConclusionsEfficacy of bevacizumab may be lower in obese patients. Among patients with Kras wild-type left-sided tumors treated with bevacizumab-based regimens, the prognosis could be worse for obese patients than that for non-obese patients. There is a need for prospectively designed studies of obese patients to prove the efficacy and dosages of bevacizumab in treatment of mCRC.Öğe Do high-risk features support the use of adjuvant chemotherapy in stage II colon cancer? A Turkish Oncology Group study(Sage Publications Ltd, 2014) Artac, Mehmet; Turha, Nazim Serdar; Kocer, Murat; Karabulut, Bulent; Bozcuk, Hakan; Yalcin, Suayip; Karaagac, MustafaBackground. A high-risk group of patients with stage II colon cancer has been identified by the results of studies in Western populations. The aim of this study was to investigate the prognostic factors of adjuvant chemotherapy in Turkish patients with stage II colon cancer. Methods. A total of 554 stage II colon cancer patients were retrospectively enrolled in the study. Three hundred fifty-three patients had received adjuvant chemotherapy (5-FU-LV, FOLFOX or FLOX) and 201 had received no adjuvant chemotherapy. T4 tumor stage, lymphovascular invasion, perineural invasion, bowel obstruction and/or perforation, <12 harvested lymph nodes, and poor differentiation were defined as high-risk factors. Results. The median age of the patients was 62 years (range 26-88). The median disease-free survival (DFS) was 58.1 months (95% CI, 47.6 months to 68.5 months) in the non-treatment group and has not been reached in the treatment group (P <0.01). In univariate analysis, patient age >60 years and T4 tumor stage were statistically significant factors that affected DFS as poor prognostic factors. Adjuvant chemotherapy reduced the risk of recurrence with statistical significance (P <0.01). In multivariate analysis, patient age >60 years and T4 tumor stage were independent risk factors affecting DFS. In addition, adjuvant chemotherapy was an independent favorable prognostic factor for DFS (P <0.01). Conclusions. Clinical and pathological risk factors in patients with stage II colon cancer may be different in the Turkish population compared to other populations. Further prospective studies in colon cancer are needed to understand the differences in biology and risk factors between races.Öğe Prevalence of K-Ras mutations in hepatocellular carcinoma: A Turkish Oncology Group pilot study(Spandidos Publ Ltd, 2015) Turhal, Nazi Serdar; Savas, Berna; Coskun, Oznur; Bas, Emine; Karabulut, Bulent; Nart, Deniz; Korkmaz, TanerHepatocellular carcinoma (HCC) is the fifth most common male-predominant type of cancer worldwide. There is no effective treatment regimen available for advanced-stage disease and chemotherapy is generally ineffective in these patients. The number of studies on the prevalence of K-Ras mutations in HCC patients is currently limited. A total of 58 patients from 6 comprehensive cancer centers in 4 metropolitan cities of Turkey were enrolled in this study. Each center committed to enroll approximately 10 random patients whose formalin-fixed paraffin-embedded tumor tissues were available for K-Ras, exon 2 genotyping. Two methods were applied based on the availability of adequate amounts of tumor DNA. In the first method, the samples were processed using TheraScreen. The genomic DNA was further used to detect the 7 most frequent somatic mutations (35G>A; 35G>C; 35G>T; 34G>A; 34G>C; 34G>T and 38G>A) in codons 12 and 13 in exon 2 of the K-Ras oncogene by quantitative polymerase chain reaction (PCR). In the second method, the genomic DNA was amplified by PCR using primers specific for K-Ras exon 2 with the GML SeqFinder Sequencing System's KRAS kit. The identified DNA sequence alterations were confirmed by sequencing both DNA strands in two independent experiments with forward and reverse primers. A total of 40 samples had adequate tumor tissue for the mutation analysis. A total of 33 (82.5%) of the investigated samples harbored no mutations in exon 2. All the mutations were identified via a direct sequencing technique, whereas none were identified by TheraScreen. In conclusion, in our patients, HCC exhibited a remarkably low (<20%) K-Ras mutation rate. Patients harboring K-Ras wild-type tumors may be good candidates for treatment with epidermal growth factor inhibitors, such as cetuximab.Öğe Real-world treatment outcomes from nationwide ONCO-colon Turkey registry in RAS wild-type patients treated with biologics first-line metastatic colorectal cancer.(Lippincott Williams & Wilkins, 2021) Kefeli, Umut; Arslan, Cagatay; Yildirim, Mahmut Emre; Isikdogan, Abdurrahman; Karadurmus, Nuri; Karabulut, Bulent; Cubukcu, Erdem[Abstract Not Availabe]Öğe Real-world treatment outcomes from nationwide ONCO-colon Turkey registry in RAS wild-type patients treated with biologics first-line metastatic colorectal cancer.(Lippincott Williams & Wilkins, 2021) Kefeli, Umut; Arslan, Cagatay; Yildirim, Mahmut Emre; Isikdogan, Abdurrahman; Karadurmus, Nuri; Karabulut, Bulent; Cubukcu, Erdem[Abstract Not Availabe]
