Huseyin Bora

Inhibition of epidural scar tissue formation after spinal surgery: external irradiation vs. spinal membrane application.

PURPOSE The scar tissue that forms after lumbar dissection is a severe complication and a cause of lumbar and radicular pain. It was recently shown that radiotherapy could inhibit peridural fibrosis after laminectomy. In this study, the efficiency of external irradiation was compared with spinal membrane application. METHOD AND MATERIALS Thirty male New Zealand rabbits underwent L5 laminectomy. Ten rabbits each received a single fraction of 900-cGy external irradiation administered by 9-MeV electron beam 24 h after the surgery. Ten other rabbits each had spinal membrane applied during laminectomy. The remaining 10 rabbits constituted the control group. All of the rabbits were killed 30 days after the laminectomy. Axial histologic sections through the laminectomy defect were evaluated. Each specimen was scored for the extent and density of fibrosis and arachnoidal adherence. RESULTS The extent and density of fibrosis and arachnoidal adherence differed significantly between the control group and the treatment groups (p < 0.05). However, the extent and density of fibrosis and arachnoidal adherence did not differ significantly between the spinal membrane and irradiation groups (p > 0.05). CONCLUSION This preliminary study showed that high-single-fraction/low-total-dose administered postoperatively can successfully inhibit postsurgical epidural fibrosis as effectively as applied spinal membrane.

Prognostic factors and treatment outcome in childhood hodgkin disease

The goals of this study included: (1) Identification of factors prognostic for event‐free survival (EFS) and overall survival (OS), and (2) Definition of risk groups for risk adapted therapy in children with Hodgkin disease (HD).

Long-term pulmonary function in survivors of childhood Hodgkin disease and non-Hodgkin lymphoma

The aim of our study was to evaluate the long‐term effects of chemotherapy and/or radiotherapy on lung function in 75 childhood Hodgkin disease (HD) and non‐Hodgkin lymphoma (NHL) survivors several years after treatment.

The Risk of Radiation-Induced Carcinogenesis after External Beam Radiotherapy of Graves’ Orbitopathy

Purpose: In order to estimate the risk of radiation-induced carcinogenesis after external beam radiotherapy of Graves’ orbitopathy, we made dosimetric measurements with thermoluminescent dosimeters in a male Rando phantom using our treatment technique. Methods: We produced dose-volume histograms from 5-mm CT slices using our treatment planning system. In this way we estimated the irradiation dose received by the main surrounding organs such as the brain, the bone and the eyeball. We use 6-MV X-ray for the treatment of Graves’ orbitopathy and our total dose is 2,000 cGy, 200 cGy per fraction. Clinical target volume was limited to the retrobulbar orbital content and medial rectus muscle, sparing the lenses, lacrimal glands and the sella turcica. All dosimetric measurements with thermoluminescent dosimeters were made 3 times. Results: We found that the dose to the right lens was 101.6 mGy and to left lens 103.4 mGy. Average absorbed doses to red bone marow, thyroid, lung, esophagus, bone surface, skin and brain, respectively, were estimated to be 523, 21, 4, 5, 81, 29, 47 mGy. Then, using tissue weighting factors specified by the International Commission of Radiation Protection, the resulting total effective dose was calculated to be 66.8 mSv. Conclusion: The risk factor for fatal cancer development derived from human epidemiological data is presently assumed to be 10% per Gy. In patients treated by our method of retro-orbital external beam radiotherapy for Graves’ orbitopathy, there is a 0.0067 (or 7 per 1,000 persons or 0.7%) risk of developing fatal radiation-induced cancer.

The effect of vitamin E on acute skin reaction caused by radiotherapy.

Ionizing radiation affects healthy organs and tissues as well as diseased tissues during radiation therapy. Skin reactions varying from acute erythema to necrosis can be seen. It has been found that vitamin E can prevent mutagenic and/or carcinogenic effects of ionizing radiation in both animals and cell cultures. This study investigated the preventative effect of antioxidant vitamin E on irradiation‐induced acute skin reactions. No protective effect of vitamin E was demonstrated. It is possible that the vehicle induced free radical exposure in the irradiated skin.

Efficacy and Safety of Concomitant Chemoradiotherapy with Cisplatin and Docetaxel in Patients with Locally Advanced Squamous Cell Head and Neck Cancers

BACKGROUND Chemoradiation (CRT) using cisplatin-based regimens has become the standard of care in the treatment of squamous cell head and neck cancers (SCHNC). The impact of taxanes as radiosensitizing agents with concurrent CRT regimens is unknown. We therefore retrospectively evaluated the efficacy and tolerability of a weekly cisplatin+docetaxel combination with CRT in locally advanced SCHNC. METHODS Sixty-six patients with locally advanced SCHNC (39.4% stage IV, 53% stage III, and 7.6% stage II) were assessed retrospectively. Total radiation dose to the PTV of gross disease (primary and/or node) was 70 Gy/ 35 fractions, 5 fractions per week. Minimum doses of 60 Gy and 50 Gy were administered to PTVs of elective high risk and low risk disease, respectively. Chemotherapy (CT) consisted of weekly cisplatin (20 mg/m2) +docetaxel (20 mg/m2) concurrently with RT. RESULTS The median age of the patients was 58 years (range, 32-77). Objective response rate was 83.3%. The 2-year progression-free survival (PFS) and overall survival (OS) were 75.7% and 78.3%, respectively. The most common grade 3 and 4 toxicities were mucositis (36.4%), nausea and vomiting (12.1%), neutropenia (4.5%). CONCLUSION Weekly cisplatin and docetaxel concurrent with RT for locally advanced SCHNC was found tolerable with high efficacy.

Prognostic Significance of Expression of CD133 and Ki-67 in Gastric Cancer

CD133 is one of the most important stem cell markers in solid cancers and Ki-67 is a marker that reflects cell proliferation. The relationships between the expression of CD133 and Ki-67 and prognosis in gastric carcinoma are unknown and need exploring. We examined 50 gastric cancer patients retrospectively in the Radiation Oncology Department of the Faculty of Medicine, Gazi University. CD133 and Ki-67 expression was examined using immunohistochemical staining. The survival rate in patients with CD133 positive expression was significantly worse than that in the patients with negative expression (p=0.04). Expression of CD133 had a positive correlation with that of Ki-67 (r=0.350; p=0.014). Multivariate analysis revealed that the expression of CD133 was an independent prognostic factor in gastric cancer (p=0.02). Conclusion, expression of CD133 may be a useful prognostic marker in gastric cancer.

Results of chemoirradiation after curative resection of locally advanced gastric cancer

To evaluate the results of post‐operative chemoirradiation for gastric carcinoma. The records of 58 patients who underwent resection for gastric carcinoma were retrospectively reviewed. Forty‐six patients had complete resection without any residual disease but with high‐risk factors of relapse. Twelve patients had microscopic residual disease. Doses of irradiation ranged from 45 to 54 Gy with a median dose of 49 Gy in 1.8 Gy fractions. Fifty‐three of the patients received 5‐fluorouracil‐based concomitant chemoradiotherapy, and all of them received chemotherapy after the completion of radiotherapy. The median survival of the entire group of patients was 21 months. The 30th month disease‐free and overall survival after surgery was 32 and 45%, respectively. The median survival time and 30th month survival rate was 23 months and 54% in patients with no residual disease, and 15 months and 18% for those with residual disease, respectively (p = 0.049). A statistically significant correlation was detected between residual disease and survival and between high‐grade tumour and survival (p < 0.05 for each). Patients with both nodal involvement and direct tumour extension beyond the gastric wall have a high risk of locoregional failure, and adjuvant chemoradiotherapy reduces local failure and improves survival.

Thyroid Abnormalities in Survivors of Childhood Cancer

Objective: To investigate the late side effects of childhood cancer therapy on the thyroid gland and to determine the risk factors for development of thyroid disorder among childhood cancer survivors. Methods: One hundred and twenty relapse-free survivors of childhood cancer (aged 6-30 years) were included in this study. The diagnoses of patients were lymphoma, leukemia, brain tumor, rhabdomyosarcoma and nasopharyngeal carcinoma (NPC). The patients were divided into two groups depending on the treatment: group 1-chemotherapy (ChT) only (n=52) and group 2-combination therapy of ChT + radiotherapy (RT) (head/neck/thorax) (n=68). Thyroid function tests, urinary iodine levels, and thyroid gland ultrasound examinations were evaluated in both groups. Results: Incidence of thyroid disease was 66% (n=79) in the survivors. The thyroid abnormalities were: hypothyroidism (HT) (n=32, 27%), thyroid nodules (n=27, 22%), thyroid parenchymal heterogeneity (n=40, 33%), autoimmune thyroiditis (n=36, 30%), and thyroid malignancy (n=3, 2%). While the incidence of HT and thyroid nodules in group 2 was significantly higher than in group 1, the incidence of thyroid parenchymal heterogeneity and autoimmune thyroiditis was similar in the two patient groups. HT and thyroid malignancy were seen only in group 2. In multivariate logistic regression analysis, a history of Hodgkin lymphoma (HL), brain tumor and NPC, as well as cervical irradiation and 5000-5999 cGy doses of radiation were found to constitute risk factors for HT. History of HL and 4000-5999 cGy doses of radiation were risk factors for thyroid nodules. Head/neck irradiation and treatment with platinum derivatives were risk factors for autoimmune thyroiditis. In univariate analysis, a history of NPC, cervical + nasopharyngeal irradiation, and treatment with platinum derivatives were risk factors for thyroid parenchymal heterogeneity. Conclusion: Our results indicate that there is especially an increased risk of HT and thyroid nodules in patients treated with combination therapy of ChT with head/neck/thorax RT. Although chemotherapeutic agents per se do not seem to cause HT, longer follow-up is needed to assess whether or not there is an increased risk for autoimmune thyroiditis and thyroid parenchymal heterogeneity after antineoplastic therapy.

Role of vascular endothelial growth factor in clinically localized prostate cancer treated with radiation therapy.

BACKGROUND Anti-vascular endothelial growth factor (Anti-VEGF) agents are a promising approach to increase the efficacy of treatment for treatment-resistant prostate cancer. AIMS To correlate vascular endothelial growth factor (VEGF) expression and outcome following radiation therapy in the treatment of clinically localized prostate cancer. STUDY DESIGN Retrospective observational study. METHODS Forty-one patients and clinically localized disease that were treated with radiation therapy were analyzed. For VEGF expression, immunoreactivity scores (IRS) were calculated using percent scores and intensity scores. Twenty-four patients were classified as having low (0 to 4 IRS) and 17 patients were classified as having high (5 to 8 IRS) VEGF expression. RESULTS The median age was 71 years, median follow-up was 5.4 years and median radiation therapy dose was 70 Gy. VEGF expression was calculated as low in 24 patients and high in 17 patients. Higher VEGF expression was observed in 6/26 patients with a low Gleason score versus 11/15 patients with a high Gleason score (p=0.02). Biochemical failure (BF) was observed in 2/24 patients with low VEGF expression versus 7/17 patients with high VEGF expression (p=0.01). In univariate analysis, having a higher Gleason score (p<0.01), being in the high risk group (p=0.03) and having higher VEGF expression (p=0.01) predicted BF after definitive radiation therapy. The biochemical failure-free survival rate at 5 years tended to be different (91% vs. 53%) when patients were grouped according to VEGF expression (p=0.06). CONCLUSION In attempt to define patients with clinically localized disease that are not sensitive to standard treatment modalities, cellular and/or molecular biological markers may be required.