Concomitant evaluation of efficiency, acute and delayed toxicities of combined treatment of radiation and CDDP on an in vivo model.

The efficiency, acute and delayed toxicities of different radio-chemotherapeutic combinations were assessed on an in vivo model (Krebs II ascitic carcinoma grafted to female Swiss mice). Mice were given whole abdomen irradiation (WAI) 2.5 to 10 Gy as a single dose (WAI). CDDP was given intraperitoneally at 0.5 to 4 mg/kg dose level, 12 hr before or after WAI. There was a relationship between dose of CDDP and increase of life span (ILS) of mice. However, WAI did not increase the life span. When a single dose of 2 mg/kg CDDP was given prior to a 2.5 Gy WAI, the ILS reached 47%. By contrast, it was only 37% when treatment sequence was reversed. When the WAI dose level was increased to 5 Gy, the ILS was not increased. The jejunal crypt cell number, determined 3 days after the last treatment, was not modified, regardless of the treatment sequence. There was no delayed renal toxicity. The study on the Krebs II ascites model confirms the tumor cell therapeutic potentiation without exacerbation of normal tissue damage.