ABSTRACT
The aim of this study was to evaluate the reduction in excision cavity volume [ECV] during the whole breast radiotherapy [WBRT]. The delineating of reduced cavity volume on secondary CT [computed tomography] might decrease the field size of boost plan. Twenty patients were treated having breast conservative surgery. At first, primary CT simulation [CT-1] was done prior to WBRT. Treatment planning was performed by a 3D treatment planning system. A CT-2 was performed after WBRT. Then the excision cavity was contoured on CT-1 and CT-2 for each patient. Boost irradiation was planned on both ECV-1 and ECV-2. In Comparison of CT-1 and CT-2: The contoured volumes for ECV-1 and ECV-2 were on average of 42.9 cm3and 23.4 cm3, respectively [p< 0.002]. The ECV-2 was reduced in 85% of the patients. Patients with ECV-1 greater than the mean value of ECV-1 [ECV-1> 35.5 cm3] had more reduction in ECV-2 than patient with ECV-1 smaller than the mean value [p < 0.000]. The volume of normal breast tissue on CT-2 was decreased from the volume of CT-1 [p< 0.03]. A significant reduction in excision cavity volume was shown during WBRT. This volume reduction made smaller sizes of boost field and remaining breast received lower doses. The reduction was more significant in patient with primary large ECV. The Secondary CT for boost planning is suggested for patients with larger cavities after WBRT
Subject(s)
Humans , Female , Radiotherapy , Tomography, X-Ray Computed , RadiationABSTRACT
Radiotherapy is an established therapeutic modality for prostate cancer. Resveratrol, a natural antioxidant, has been shown to inhibit carcinogenesis and to block the process of tumor initiation and progression. No data is available on the response of cellular spheroid to Reseveratol. In this study we have examined the effect of Resveratol on the radiation response of human prostate cell line DU145 in monolayer and spheroid cultures. Radiosensitivity was assessed using viability and colony formation assay. Apoptosis and necrosis were assessed using acridine orange/ ethidium bromide double staining. The colony formation assay did not show any significant radio-sensitizing effect, but apoptosis assay showed significant radio-sensitizing effect of Resveratol on DU145 cells grown as monolayer. In the spheroid cells the results of apoptosis test were not significant and corresponded closely to the result of survival curve. While Resveratol could sensitize DU145 cells in monolayer to ionizing radiation, it did not have any effect on sensitivity of cells cultured in spheroid cultures
ABSTRACT
Rad51 is a protein with critical role in double strand break repair. Down-regulation of this protein has a significant effect in radiosensitivity of some cell lines like prostate carcinoma. Compared to monolayer cell culture model, the spheroids are more resistant to radiation. The aim of the current study was to determine the Rad51 protein level in DU145 spheroids, and monolayer cells before and after exposure to gamma irradiation. In the present study, western blot was used to determine the level of Rad51 protein in DU145 cell line grown as monolayer and spheroid. Western blot analysis showed that in the spheroid cells, Rad51 had an elevated level before and after radiation in comparison with monolayer cells. Higher doses of radiation induced elevated expression of Rad51 protein in both culture models. The level of at protein after exposure to gamma rays had been time dependent. Rad51 might act as a mediator of radiation resistance in tumor cells. Repression of Rad51 activity could be a prominent strategy to overcome radiation resistance of tumors
Subject(s)
Prostatic Neoplasms , Radiation ToleranceABSTRACT
Several cell lines when cultured under proper condition can form three dimensional structures called multicellular tumor spheroids. Tumor spheroids are valuable in vitro models for studying physical and biological behavior of real tumors. A number of previous studies using a variety of techniques have shown no relationship between radiosensitivity and DNA strand breaks in monolayer and spheroid model of cell culture. In the present study, the radiosensitivity of cells grown as monolayer and spheroid were measured with colony assay and the role of DNA strand breaks in this sensitivity was examined using single cell gel electrophoresis assay also known as Comet assay. In the present experiment, spheroids showed more radioresistance than monolayers as judged by the number of colonies which they produced after radiation. Under the same experimental conditions, less level of DNA damage was detected in spheroids using "comet assay" technique. It was concluded that the loss of radioresistance which was observed in monolayer cultures might have been attributed to the higher level of DNA damage occurred in the cells