The antitumor efficiency of combined electrochemotherapy and single dose irradiation on a breast cancer tumor model.
BACKGROUND
The aim of this study was to investigate the antitumor effectiveness of electrochemotherapy with cisplatin combined with suboptimal radiotherapy doses. Tumor radiosensitization was evaluated on large invasive ductal carcinoma tumors in Balb/C mice.


METHODS
Tumors of an average volume of 630 mm(3) were treated with cisplatin, electric pulses, radiotherapy, electrochemotherapy, alone as well as in appropriate combinations. Tumors were irradiated with Cobalt-60 γ-rays at doses 3 Gy and 5 Gy in combination with electrochemotherapy using cisplatin. Controls included each of the treatments alone as well as the combination of the radiotherapy with electric pulses alone or with cisplatin alone. Antitumor effectiveness was evaluated by tumor growth delay, tumor-doubling time, inhibition ratio and the objective response rates.


RESULTS
As anticipated, electrochemotherapy was more effective than the treatment with cisplatin alone or the application of the electric pulses alone. When treatments were combined with tumor irradiation at either 3 or 5 Gy, the combination with electrochemotherapy was more effective: at 5 Gy, 2 animals out of 8 were in complete remission 100 days later. In general the higher 5 Gy dose of γ-radiation was more effective than the lower one of 3 Gy.


CONCLUSIONS
The results of our study demonstrate that irradiation doses, 3 Gy or 5 Gy, increase the antitumor effectiveness of electrochemotherapy with cisplatin on invasive ductal carcinoma tumors. Good antitumor results were achieved in experimental tumors with a size comparable to clinical lesions, demonstrating that this three-modality combined treatment is useful for the treatment of large lesions even at sub-optimal radiotherapy doses.
Department of Medical Physics, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran ;  Faculty of Science, University of Geneve, Geneve, Switzerland.
Elham
E
Raeisi
Seyed Mahmoud Reza
SM
Aghamiri
Azin
A
Bandi
Negar
N
Rahmatpour
Seyed Mohammad
SM
Firoozabadi
Sedigheh Amini
SA
Kafi-Abad
Lluis M
LM
Mir