Effects of matrix-associated chemotherapy in combination with irradiation in vivo.

Delay of tumor growth in RIF-1 fibrosarcomas in C3H mice was studied, comparing ip delivery of 5-fluorouracil (5-FU) or cisplatin (cis-DDP) versus collagen matrix-associated intratumoral delivery of drug with and without irradiation to a total dose of 1,500 cGy. For cis-DDP (6 mg/kg), the number of days required for treated tumors to attain three times their original treatment volume was 6.2 +/- 1.6 SE for ip drug and 7.0 +/- 1.3 for intratumoral drug matrix. The use of the vasoactive agent epinephrine (1 mg/kg) in the matrix resulted in a growth delay of 10.1 +/- 2.0 days. Irradiation given 60 minutes after drug administration enhanced the delay of tumor growth to 19.2 +/- 2.6 days for systemic drug and 16.7 +/- 2.5 days for matrix-associated drug. The delay of tumor growth for irradiation plus matrix-associated cis-DDP containing epinephrine was 33.0 +/- 5.4 days. X-rays alone caused a tumor growth delay of 11.2 +/- 1.3 days. Similar results were found for 5-FU at a dose of 50 mg/kg, although the epinephrine in the matrix was not as effective.