Histamine combined with melphalan in isolated limb perfusion for the treatment of locally advanced soft tissue sarcomas: preclinical studies in rats.

PURPOSE: To evaluate the potential benefit of histamine combined with melphalan in the isolated limb perfusion (ILP) as an alternative to TNF-alfa and melphalan combination, for the treatment of irresectable soft tissue sarcomas of the limbs in Brown Norway (BN) rats. METHODS: 20 BN rats had small fragments of syngeneic BN-175 fibrosarcoma inserted on the right hind limb. In 7-10 days the tumor reached a median diameter of 12-15 mm and they were randomly divided in four groups (sham, melphalan, histamine and escalating doses of histamine combined to melphalan) being submitted to experimental ILP for 30 minutes. Tumors were measured daily with a caliper and the volume was calculated. RESULTS: Response curves showed a significant effect of the combination of histamine 200 mg/mL with melphalan, with 66% overall response, including 33% complete responses (p< 0.01). There were no systemic collateral effects and locally only mild temporary edema was observed for some animals treated with histamine. CONCLUSION: Histamine combined with melphalan had a promising effect in the ILP warranting future studies to better explore the mechanism of action as well as its potential use in organ perfusion.