Abstracts
1998 Digestive Disease Week

#1033

ARTERIAL EMBOLISATION SIGNIFICANTLY IMPROVES THE HYPERTHERMIC EFFECT OF LASER-INDUCED THERMO-THERAPY IN LIVER METASTASIS IN RATS. D. Albrecht, C. Germer, C. Isbert, A. Roggan, HP. Ritz, D. Schuppan and H.J. Buhr. Department of Surgery, Medical Center Benjamin Franklin, Freie Universität Berlin, Germany.

Introduction and objective: Laser-induced thermotherapy (LITT) is a method for destroying malignant tumors. The aim of this animal experimental study was to examine whether the temporary microembolization of the tumor vascular bed with starch microspheres (Spherex®) before LITT leads to an increase in the effective volume. Material and methods: The colon carcinoma cell line CC-531 (106 cells/0.1 ml) was used to induce liver tumors. Animals were grouped into LITTmono (n=15), Embolizationmono(n=15), LITTembolization(n=15). Intrahepatic temperatures were measured 6 mm from the applicator. A catheter was implanted into the gastroduodenal artery for starch microsphere application. Tumor vitality was determined immunohistologically by the bromodeoxyuridine-AK (BrdU) reaction and HE sections 24 h, 7 and 28 days after treatment. Results: The analysis of intraoperative temperature curves demonstrated significantly higher values for LITTembolization at 68°C ( ± 1) than for LITTmono at 57°C ( ± 1). Vital tumor tissue was macroscopically and immunohistologically found in only 1 animal in the LITTembolization group (7d) (p<0.01) (Tab.). Macroscopic and immunohistological examinations showed tumor growth in LITTmono and Embolizationmono 24 h, 7 and 28 days after treatment. The LITTmono group had a clearly reduced BrdU reaction in the tumor periphery compared to embolizationmono. Correspondingly, tumor diameters in LITTmono after 21 days were a mean of 3 mm smaller than in Embolizationmono.

	Vital tumor tissue
Parameter	24 h (n = 5)	7 d (n = 5)	21 d (n = 5)
LITTmono (n = 15)	4/5	4/5	5/5
Embolizationmono (n = 15)	5/5	4/5	5/5
LITTembolization (n = 15)	0/5	1/5	0/5

Conclusions: 1. LITTmono led to a clear delay in tumor growth under the selected testing conditions. 2. The application of starch microspheres enabled the elimination of the "cooling effects" of liver perfusion and resulted in a significant increase in the hyperthermal effect of LITT. 3. This synergetic effect allows LITT treatment of even larger tumors.

With the support of the German Research Foundation; project A1-143/1-1.

Copyright 1996 - 1998, SSAT, Inc. Revised 29 June 1998.