Joerg Pelz

Background and aims There is controversy about the effect of the influence of hyperthermia and chemotherapeutic agents on the healing of intestinal anastomosis. The effects of hyperthermic intraperitoneal chemoperfusion (HIPEC) of wound healing after colonic anastomosis were investigated in a rat model. Materials and methods Thirty-six Wag/Rija rats were randomized into three groups of 12 animals each: group I: control (only colonic anastomosis was performed) (n = 12); group II: HIPEC (mitomycin C in a concentration of 20 mg/m² (n = 12) colonic anastomosis was performed before HIPEC; group III: HIPEC (mitomycin C in a concentration of 20 mg/m² (n = 12) colonic anastomosis was performed after HIPEC. Bursting pressure and bursting sites were recorded 4 and 10 days after intervention. Collagen deposits, inflammation and foreign body reactions were evaluated. Results Lower bursting pressure and lost of collagen were found in both HIPEC groups and compared with the control group. There was almost no difference between both HIPEC groups. They were noted overwhelmingly at the anastomosis in the HIPEC group. The degree of collagen accumulation was well-correlated with bursting pressure. Conclusion These results have shown that hyperthermic intraperitoneal chemoperfusion (HIPEC) impairs wound healing in colonic anastomosis in rats.

Background: In selected patients with peritoneal carcinomatosis from colorectal cancer prognosis can be improved by hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery. The aim of this study was to evaluate the tumor response of peritoneal carcinomatosis in tumor-bearing rats treated with HIPEC. Methods: CC531 colon carcinoma (2,5 × 10⁶ cells), implanted intraperitoneally in Wag/Rija rats, was treated by hyperthermic intraperitoneal chemotherapy. After 10 days of tumor growth the animals were randomized into five groups of six animals each: group I: control (n = 6), group II: sham operated animals (n = 6), group III: hyperthermic intraperitoneal perfusion (HIP) without cytostatic drugs, group IV: HIPEC with mitomycin C in a concentration of 15 mg/m² (n = 6), group V: mitomycin C i.p. alone in a concentration of 10 mg/m² (n = 6). After 10 days the extent of tumor spread and histological outcome were analysed by autopsy. Results: All control animals developed extensive intraperitoneal tumor growth. Histological tumor load was significantly reduced in group III and group V and was lowest in group IV. In group II tumor load was significantly higher than in group I. Implanted metastases were significantly decreased in group IV compared with group I and group II. Conclusion: These findings indicate that HIPEC is an effective treatment for peritoneal carcinomatosis in this animal model. HIPEC reduced macroscopic and microscopic intraperitoneal tumor spread.

Background: Cytoreduction followed by hyperthermic intraperitoneal chemotherapy (HIPEC) improves survival in patients with peritoneal carcinomatosis of colorectal origin. Animal models are important in the evaluation of new treatment modalities. The purpose of this study was to devise an experimental setting which can be routinely used for the investigation of HIPEC in peritoneal carcinomatosis. Methods: A new peritoneal perfusion system in tumor bearing rats were tested. For this purpose CC531 colon carcinoma cells were implanted intraperitoneally in Wag/Rija rats. After 10 days of tumor growth the animals were randomized into three groups of six animals each: group 1: control (n = 6), group 2: HIPEC with mitomycin C in a concentration of 15 mg/m² (n = 6), group III: mitomycin C i.p. as monotherapy in a concentration of 10 mg/m² (n = 6). After 10 days, total tumor weight and the extent of tumor spread, as classified by the modified Peritoneal Cancer Index (PCI), were assessed by autopsy of the animals. Results: No postoperative deaths were observed. Conjunctivitis, lethargy and loss of appetite were the main side effects in the HIPEC group. No severe locoregional or systemic toxity was observed. All control animals developed massive tumor growth. Tumor load was significantly reduced in the treatment group and was lowest in group II. Conclusion: The combination of hyperthermia with MMC resulted in an increased tumoricidal effect in the rat model. The presented model provides an opportunity to study the mechanism and effect of hyperthermic intraperitoneal chemotherapy and new drugs for this treatment modality.

Background: The aim of this experimental study was to determine the effect of mild hyperthermia on tumor response and angioneogenesis in an isolated limb perfusion model with a human melanoma xenograft. Methods: A human melanoma xenograft was implanted into the hindlimbs of 30 athymic nude rats. The animals were randomized into five groups: group I: control, group II: sham group, group III: external hyperthermia with a tissue temperature of 41.5°C for 30 minutes without ILP, group IV: normothermic ILP (tissue temperature 37°C for 30 minutes, group V: hyperthermic ILP (tissue temperature 41.5°C for 30 minutes). Tumor response was evaluated by tumor size determination and immunohistochemical analysis 6 weeks postoperatively. Tissue sections were investigated for expression of CD34 and basic fibroblast growth factor (bFGF). Results: Average tumor volumes of the controls (I) increased from 105 mm³ to 1388 mm³. In the sham operated group (II) tumor volumes were significantly larger than in group I. Tumor volumes in group IV were significantly smaller than in group I and lowest in group V. There were no significant differences in size between group I and group III after six weeks. In group III and IV each, 5 animals showed tumor progression and one had a partial tumor response. In group V only 2 animals showed tumor progression. Immunhistochemical analysis of the tissue sections demonstrated that angioneogenesis was more pronounced in group II than in group I and less pronounced in group IV and V compared with group I. Conclusions: Our results suggest that even a surgical manipulation such as a skin incision promotes tumor growth, probably by induction of growth factors like bFGF. External hyperthermia of 41.5°C tissue temperature for 30 minutes only has no impact on tumor growth and angioneogenesis in vivo.

Angiomyolipome sind benigne hamartöse Neoplasien, die sporadisch oder in Assoziation mit der tuberösen Hirnsklerose auftreten. Diese Weichteiltumoren betreffen meist die Nieren, seltener aber auch andere Organe. Der Tumor ist charakterisiert durch spindelförmige Muskelzellen, Fettgewebsanteile und hyalinisierte Gefäße. Wir berichten über einen 74 Jahre alten Mann, bei dem nach einer Hemikolektomie rechts und histologischer Aufarbeitung des Tumors ein multifokales Angiomyolipom im Operationspräparat vorlag. Bei dem Patienten selbst und in der Familienanamnese ist keine tuberöse Hirnsklerose zu erheben gewesen. Extrarenale Angiomyolipome sind sehr selten und dies ist nach unserer Erkenntnis der erste berichtete Fall eines multifokalen Angiomyolipoms des Kolons. Angiomyolipoma is one of the benign hamartomas that is found sporadically or associated with tuberous sclerosis. It is a rare soft tissue tumor involving mostly the kidneys, sometimes other visceral organs. The tumor is composed of smooth muscle cells, adipocytes and small sized hyalinized vessels. We present the case of a 74-year-old man with a bifokal angiomyolipoma of the colon. This diagnosis was confirmed at surgery, where a partial colectomy was performed. Histologic examination disclosed the tumor. The patient had no signs of family history of tuberous sclerosis. Extrarenal angiomyolipoma is rare and this may be the first report of bifocal colonic angiomyolipoma.