[Intratumoral chemotherapy in an experimental animal model: another therapeutic possibility in cancerology].
OBJECTIVE: Assess the efficacy of intratumoral chemotherapy in a colonic tumor model implanted subcutaneously in the BD IX rat. METHOD: In order to determine their antitumoral effect, 5 anticancer drugs were administered via intravenous and direct intratumoral routes 2 or 10 days after subcutaneous inoculation of tumoral cells. Intratumoral diffusion was evaluated using Patent blue injected directly into the tumoral tissue. Cisplatinum was administered via intratumoral, intravenous and intra-arterial routes to determine the intratumoral and intrarenal concentrations achieved with each of these administration routes. Cisplatinum was also administered via intravenous and intratumoral infusion for 30 minutes to determine the antitumoral effect of each of these routes. RESULTS: Mitomycin and cisplatinum inhibited growth of tumors which had not yet become established and caused advanced stage tumors to regress. For early stage tumors, the intratumoral route was always more effective than the intravenous route. Patent blue diffusion demonstrated a nonhomogeneous intratumoral distribution. Compared with intravenous or intra-arterial infusion, intratumoral infusion gave much higher concentrations of cisplatinum within the tumors and reduced systemic diffusion. At 7 weeks, the antitumoral effect was equivalent for the 2 administration routes while at 13 weeks, the intratumoral treatment was more effective than the intravenous treatment. CONCLUSION: These findings in an experimental animal model demonstrate that intratumoral chemotherapy is more effective than intravenous chemotherapy. It is however still impossible to consistently cure tumors induced in animals.