[Scalpel and CO2 laser in the animal experiment. A comparative study of inoculation tumors of the mouse].

The study hereby submitted has been designed to show whether there are any differences between using a conventional knife or a CO2-laser when excising and grafting tumors in animal experiments. The animals were C57Bl/6 mice, the tumor was the Lewis lung carcinoma. Eight days after tumor inoculation into the subcutaneous layer of the back, 213 mice were treated by tumor excision either with a conventional knife or a CO2-laser. 86 excised tumors were cut and the tumor surface was swabbed into the subcutaneous layer on the nape of 86 tumor-free mice. Survival times of the laser-operated animals were insignificantly longer. However, small tumors showed markedly longer survival times. The interval without recurrence was longer for all tumor sizes when the laser was used (p less than 0.005). The laser method yielded lower growth rates when the tumor surface was swabbed into tumor-free mice (p less than 0.0001). Histological and cytological tests of the laser-excised and -swabbed specimen demonstrated a high rate of cell destruction. Therefore, the CO2-laser seems to have some importance in cases where the incision is made close to the tumor or where the tumor surface may be lesioned.