World Federation of Neuro Oncology II

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Description

Poster presentaton Abscopal effect on subcutaneously implanted N29 rat glioma tumours, from contra-lateral treatments with pulsed electric fields, radiation therapy and immunization with syngeneic interferon-gamma secreting tumor cells. Bertil R.R. Persson1,4), Catrin Bauréus Koch1,4), Gustav Grafström1,4), Crister Ceberg1,4), Bengt Widegren2,4) and Leif G. Salford3,4). Background: Effects of radiation therapy on cancer tumors outside of the radiation field is a phenomenon as abscopal effect. The aim of the present study is to study the effect of immunization with syngeneic IFN secreting cells on Abscopal regression of contra-lateral subcutaneously implanted rat glioma tumors treated with radiation therapy in combination with pulsed electric field treatment. Material and Methods: The study was performed on rats of the Fischer-344 strain with rat glioma N29 tumors implanted subcutaneously on the flank or on both the right treated hind leg and the left untreated hind leg. Pulsed electric field with 16 exponentially decaying pulses with a maximum electric fields strength of 1300 V/cm and t1/e= 1 ms were first applied to the tumors. Then within 5 min radiation treatment was given in daily fractions of 5 Gy, to a total absorbed dose of 20 Gy. The animals were arranged into one group of controls and 3 groups of various treatments: Pulsed Electric Fields only (PEF), Radiation therapy (RT) with 60Co-gamma radiation only (5 Gy per session), or combination of Pulsed Electric Fields and Radiation therapy. Tumors were treated 4 consecutive days at about 4 weeks after inoculation, when a solid tumor has grown to a diameter of 1-1.5 cm). Once weekly for three weeks, the animals were given intraperitoneally injections of irradiated, modified N29 tumor cells, secreting interferon-gamma (IFN-). The Abscopal effect was evaluated by comparing the growth rate of the untreated contra lateral tumors with the treated tumors. Results: Fitting the data obtained from consecutive measurements of tumor volume (TV) of each individual tumor to an exponential model TV = TV0 exp[TGR t] estimated the tumor growth rate (TGR %per day) after the day of treatment (t = 0). Totally 5 experimental series were performed with total number of 141 rats, of which 45 were controls and the number of animals in each treatment group was around 30. The TGR of both types of tumors treated with the combination of Pulsed electric fields and radiation therapy are significantly decreased compared to the controls. The tumor growth rate for both types of tumors is significantly decreased by combined treatment with pulsed electric fields and radiation therapy compared to radiation therapy alone. Conclusion: There was no significant difference in contra lateral tumor growth in animals without treatment and those treated with IFN- secreting cells only. But a significantly decreased growth rate of the untreated tumor was observed, in animals given Pulsed Electric Fields (PEF) and Radiation Therapy combined with IFN- secreting cells. These results indicate that the most pronounced Abscopal effect was achieved using Pulsed Electric Fields and Radiation Therapy combined with immunization using syngeneic tumor cells.
Period2005 May 52005 May 8
Event typeConference
LocationEdinburgh, United KingdomShow on map

UKÄ subject classification

  • Medical and Health Sciences