Ufuk Abacioglu

Critical appraisal of RapidArc radiosurgery with flattening filter free photon beams for benign brain lesions in comparison to GammaKnife: a treatment planning study.

BackgroundTo evaluate the role of RapidArc (RA) for stereotactic radiosurgery (SRS) of benign brain lesions in comparison to GammaKnife (GK) based technique.MethodsTwelve patients with vestibular schwannoma (VS, n = 6) or cavernous sinus meningioma (CSM, n = 6) were planned for both SRS using volumetric modulated arc therapy (VMAT) by RA. 104 MV flattening filter free photon beams with a maximum dose rate of 2400 MU/min were selected. Data were compared against plans optimised for GK. A single dose of 12.5 Gy was prescribed. The primary objective was to assess treatment plan quality. Secondary aim was to appraise treatment efficiency.ResultsFor VS, comparing best GK vs. RA plans, homogeneity was 51.7 ± 3.5 vs. 6.4 ± 1.5%; Paddick conformity Index (PCI) resulted 0.81 ± 0.03 vs. 0.84 ± 0.04. Gradient index (PGI) was 2.7 ± 0.2 vs. 3.8 ± 0.6. Mean target dose was 17.1 ± 0.9 vs. 12.9 ± 0.1 Gy. For the brain stem, D1cm3 was 5.1 ± 2.0 Gy vs 4.8 ± 1.6 Gy. For the ipsilateral cochlea, D0.1cm3 was 1.7 ± 1.0 Gy vs. 1.8 ± 0.5 Gy. For CSM, homogeneity was 52.3 ± 2.4 vs. 12.4 ± 0.6; PCI: 0.86 ± 0.05 vs. 0.88 ± 0.05; PGI: 2.6 ± 0.1 vs. 3.8 ± 0.5; D1cm3 to brain stem was 5.4 ± 2.8 Gy vs. 5.2 ± 2.8 Gy; D0.1cm3 to ipsi-lateral optic nerve was 4.2 ± 2.1 vs. 2.1 ± 1.5 Gy; D0.1cm3 to optic chiasm was 5.9 ± 3.1 vs. 4.5 ± 2.1 Gy. Treatment time was 53.7 ± 5.8 (64.9 ± 24.3) minutes for GK and 4.8 ± 1.3 (5.0 ± 0.7) minutes for RA for schwannomas (meningiomas).ConclusionsSRS with RA and FFF beams revealed to be adequate and comparable to GK in terms of target coverage, homogeneity, organs at risk sparing with some gain in terms of treatment efficiency.

V30 as a predictor for radiation-induced hypothyroidism: a dosimetric analysis in patients who received radiotherapy to the neck.

IntroductionThe purpose of this study is to evaluate the possible predictors of thyroid disorders after neck radiotherapy, with a focus on radiation dose-volume factors.MethodsThyroid function was measured in 100 patients who had received radiotherapy to the neck, including the thyroid. All radiation-induced thyroid dysfunctions were determined with an endpoint of abnormal thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and thyroxine (fT4) and thyroid peroxidase antibodies and (TPA). The total volume of the thyroid, mean radiation dose to the thyroid (Dmean) and thyroid volume percentage that received radiation doses of 10–50 Gy (V10-V50) were calculated in all patients. The evaluated risk factors for thyroid dysfunction included dose-volume parameters, sex, age, previous surgery, chemotherapy and comorbidity.ResultsThere were 52 patients with hypothyroidism and V30 (p = 0.03), thyroid volume (p = 0.01) and Dmean (p = 0.03) appeared to be correlated with hypothyroidism in univariate analysis. However, there was not association found in multivariate analysis for these factors.ConclusionsThyroid disorders after radiation therapy to the neck still represent a clinically underestimated problem. V30 may be a useful tool for evaluating the risk of hypothyroidism when determining an individual patient’s treatment.

Prophylactic feeding with immune-enhanced diet ameliorates chemoradiation-induced gastrointestinal injury in rats.

Purpose: To investigate the protective effect of immune-enhanced diet (IED) on chemoradiation-induced injury of the gastrointestinal mucosa. Materials and methods: Forty-eight Sprague-Dawley rats were divided into control (C, n = 6), irradiation (IR, n = 14), fluoropyrimidine (5-FU, n = 14)-treated, IR + 5-FU (n = 14)-treated groups. Half of each irradiated and/or 5-FU-treated groups were previously fed with IED containing arginine, omega-3-fatty acids and RNA fragments, while the other half were fed a standard rat diet (SD) for eight days before the induction of IR or injection of 5-FU. In IR groups, whole abdominal irradiation (11 Gy) was performed with 6 MV photons. In the 5-FU groups, fluoropyrimidine (100 mg/kg) was administered intraperitoneally 30 min prior to irradiation. All animals were sacrificed on the 4th day of IR or 5-FU injection. Results: Bacterial colony counts in the ceca and mesenteric lymph nodes of IED-fed rats, which have received either 5-FU and/or irradiation were significantly lower than the corresponding SD-fed groups. Morphometric results revealed that gastric, ileal and colonic injuries were less in IED-treated IR or IR + 5-FU + IED groups, as compared to SD-fed groups. However, IED did not alter DNA fragmentation ratios. Conclusion: Prophylactic feeding of IED has a protective effect on chemoradiation-induced gastrointestinal injury, which appears to involve the eradication of bacterial overgrowth.

Functional and clinical evaluation of renal injury in patients treated with adjuvant chemoradiotherapy for gastric cancer: Low dose and comorbidity considerations

Abstract Aim To analyze the dosimetric factors affecting long-term renal function in patients with gastric cancer following postoperative radiotherapy with concomitant chemotherapy to the upper abdomen. Methods Between January 2005 and July 2010, 13 patients treated with three-dimensional conformal radiotherapy and concurrent fluorouracil-based chemotherapy (CRT) were included in this analysis. After a median follow-up of 55 months, creatinine, glomerular filtration rate (GFR), total kidney and left kidney volumes, before and after CRT and mercaptoacetyltriglycine (MAG3) scintigraphy, were used to evaluate the renal function and were correlated with the dosimetrics data. Results Significant correlations were found in the loss of left kidney volume and V35 (20.6%) (p = 0.035) and V40 (15.7%) (p = 0.031) and in the loss of relative functional contribution of the main kidney and V35 Gy (p = 0.027) and V40 Gy (p = 0.019). In patients with a slightly low basal GFR (n = 6), the relative functional contribution of the left kidney significantly decreased, regardless of the dosage. Conclusion Functional renal impairment without any clinical signs or symptoms can be observed in low doses after radiotherapy. Careful treatment planning and a detailed evaluation of the functional renal capacity before treatment may help to reduce late renal toxicity.

The effect of magnesium and vitamin E pre-treatments on irradiation-induced oxidative injury of cardiac and pulmonary tissues in rats: a randomized experimental study.

OBJECTIVE The aim of this study was to investigate the effect of pre-treatment with the free radical scavenging molecules, magnesium and vitamin E, on lipid peroxidation to limit radiation-induced heart and lung injury. METHODS Female Sprague-Dawley rats were divided into 4 groups by a simple randomization method as saline-treated control (n=4), saline-treated irradiated (IR; n=6), magnesium sulphate-treated irradiation (IR) (Mg+IR; n=6) and vitamin E-treated IR (vit E+IR; n=6), respectively. The animals were given either saline, Mg (600 mg/kg/day) or vit E (100 mg/kg/day) intraperitoneally for five days prior to irradiation. Twelve hours after the fifth injection, animals in irradiation groups were irradiated to 20 Gy using 6 MV photons in linear accelerator. Twenty-four hours later cardiac and lung tissue samples were obtained for determination of myeloperoxidase activity (MPO), malondialdehyde (MDA) levels, and luminol and lucigenin levels measured by chemiluminescence (CL) methods. RESULTS No significant changes were observed between cardiac and pulmonary MDA and CL results of the experimental groups. However, cardiac and pulmonary MPO activities in the saline-treated IR group were increased as compared to control group (p<0.05 for all), while in the Mg-pretreated and vit E pretreated groups neutrophil infiltration was reduced, reaching to statistical significance only in the Mg-pretreated group (p<0.05). CONCLUSION Prophylactic use of magnesium sulfate has limited the infiltration of neutrophils to both the cardiac and pulmonary tissues at the early 24 h of irradiation. However, how limiting neutrophils as the sources of free radicals and inflammatory mediators would alter oxidative stress of heart and lung tissues in the long-term is not clear yet.

Chemoradiotherapy Experience In Locally Advanced Esophagial Cancer

Amac: Bu calismada lokal ileri evre ozefagus kanseri tanisiyla neoadjuvan/ definitif kemoradyoterapi (KRT) uygulanan hastalarin sonuclarinin bildirilmesi amaclanmistir. Hastalar ve Yontem: Histolojik tanisi skuamoz hucreli 10, adenokarsinom 4, adenoskuamoz karsinom 1 olan, T3N0M0 5 veya T3N1M0/T4N0M0 10, toplam 15 hasta geriye donuk olarak incelendi. Ortanca radyoterapi dozu 50 Gy (1,8-2 Gy/gun, 5 fraksiyon/hafta) olup es zamanli kemoterapi radyoterapinin ilk ve son hafta sisplatin ve 5-florourasil olarak uygulandi. Bulgular: Es zamanli kemoterapinin kesintisiz uygulanabilirlik orani %80 idi. Medyan takip 15 ay (aralik, 3-70 ay) idi. Neoadjuvan olarak tedavi edilen bes hastadan birinde lokal progresyon, ucunde uzak metastaz izlendi. Bastan definitif KRT planlanan hastalardan ucune (%30) evrede kuculme izlenerek cerrahi onerildi. Iki yillik lokal kontrol (LK) %22, uzak metastazsiz sagkalim (UMSK) %45 ve genel sagkalim (GSK) %31 olarak saptandi. Derece III disfaji orani %6 idi. Sonuc: Lokal ileri evre ozefagus kanserinde tedavi tartismalidir. Cerrahi sansini elde eden hastalarda daha uzun sagkalim ve lokal kontrol bildirilirken uclu modalite tedavilerin yapilabilirligi merkezin deneyimi ile sinirlidir. Bu nedenle tum hastalar bireysel olarak ve multidisipliner yaklasim ile degerlendirilmelidir. (Marmara Universitesi Tip Fakultesi Dergisi 2012;25:74-7) Anah tar Ke li me ler: Cerrahi, Lokal ileri evre, Kemoradyoterapi, Ozefagus kanseri Abstract