Metabolic activity and DNA integrity in human hepatic metastases after interstitial laser coagulation (ILC)

Abstract

Background and Objective For investigations into interstitial laser coagulation (ILC) of solid tumors, tissue whitening is used as a parameter for the extent of coagulation. This obvious demarcation is associated with global thermal denaturation, but it is not clear whether this finding is a good indicator of the exact outer boundary of the lethal tissue effect. Study Design/Materials and Methods ILC with portal inflow occlusion was performed in human hepatic metastases of colorectal carcinoma directly after surgical resection (n = 5) or before surgical resection (n = 5) with laser parameters adapted to tumor diameter. Mitochondrial NADH-diaphorase activity and DNA integrity were assessed by histoenzymatic staining. Results In 7 of 10 tumors (mean diameter, 3.7 cm), an area of macroscopic coagulation (mean diameter, 4.2 cm) encircled the tumor in all three axes. Macroscopic coagulation corresponded to absent metabolism and disintegrated DNA. Furthermore, the macroscopic volumes of coagulation produced in tumor were comparable to the dimensions in normal porcine liver with the same laser parameters. Conclusion ILC with portal inflow occlusion results in areas with complete cell avitality in the zone of tissue whitening in human hepatic liver metastases. Lasers Surg. Med. 28:80–86, 2001. © 2001 Wiley-Liss, Inc.