BACKGROUND.
Although percutaneous microwave coagulation is relatively noninvasive therapy for patients with hepatic tumors, coagulation of tumors is sometimes incomplete and local recurrence occurs. The authors hypothesized that the cause of incomplete coagulation was a cooling effect in surrounding hepatic blood flow. To prove this hypothesis and to improve the efficacy of this therapy, they interrupted hepatic blood flow during the treatment and measured the amount of tumor tissue coagulated by microwave.
METHODS.
The authors first performed an animal experiment on pigs. After laparotomy, the liver of an anesthetized pig was coagulated by microwave with or without interruption of hepatic blood flow; the interruption was achieved by squeezing hepatic blood vessels. Next, the authors applied the microwave coagulation percutaneously to 25 human patients with primary or metastatic carcinoma in the liver with or without intraoperative temporary interruption of hepatic blood flow; the interruption was achieved by inflating balloon catheters inserted in the hepatic blood vessels through femoral vessels.
RESULTS.
The greatest dimension of area of normal liver tissue coagulated by microwave with blood flow interruption was significantly (P ฯฝ 0.001) larger (18.8 ฯฎ 1.0 mm, n ฯญ 4) than without it (9.8 ฯฎ 1.7 mm, n ฯญ 4) in the experiment with pigs.
In human hepatic tumors, the greatest dimension of the area coagulated by microwave with blood flow interruption was also significantly (P ฯฝ 0.001) larger (41.1 ฯฎ 9.3 mm, n ฯญ 14) than without it (26.9 ฯฎ 8.5 mm, n ฯญ 11). The local recurrence rate of the tumor during a period of 6 months after the treatment was lower (P ฯฝ 0.05) with blood flow interruption (7%) than without it (45%).
CONCLUSIONS.
Intraoperative interruption of hepatic blood flow increases the areas of primary and metastatic hepatic tumors coagulated by microwave. It is expected to increase the efficacy of percutaneous microwave coagulation therapy for patients with hepatic tumors.