Local hyperthermia using a low powered Nd: YAG laser for pancreatic and gastric carcinoma.

The use of local interstitial hyperthermia using a low powered Nd: YAG laser (known as laserthermia) has been studied both in vivo and in vitro on two gastrointestinal carcinomas. Human pancreatic carcinoma subcutaneously transplanted into nude mice (n = 28) was treated using an interstitially placed frosted sapphire probe with a Nd: YAG laser at 3 watts maintaining a temperature increase of 42 degrees C - 43 degrees C for up to 20 minutes. Seven days after treatment, a marked necrosis of the pancreatic tumor was found resembling an ischemic infarction. The potential cytocidal effect of heat and low powered Nd: YAG laser energy was also tested in vitro using three different kinds of human gastric and pancreatic cancer cells. The cytocidal effect of heat was potentiated by the photolytic effect of the low powered Nd: YAG laser energy.