Reoxygenation in the SCCVII tumor after KU-2285 sensitization plus single or fractionated irradiation

Journal Article · Wed Jun 15 04:00:00 EDT 1994 · International Journal of Radiation Oncology, Biology and Physics; (United States)

DOI:https://doi.org/10.1016/0360-3016(94)90461-8· OSTI ID:6946443

Shibamoto, Yuta; Kitakabu, Yoshizumi; Murata, Rumi; Oya, Natsuo; Shibata, Toru; Sasai, Keisuke; Takahashi, Masaji; Abe, Mitsuyuki ^[1]

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1. Kyoto Univ. (Japan)

Because reoxygenation of solid tumors after irradiation with a hypoxic cell sensitizer has never previously been investigated, the authors assessed the reoxygenation in SCCVII tumors after treatment with KU-2285 plus single or fractionated irradiation. KU-2285 (100 mg/kg) was injected intraperitoneally into C3H mice bearing 1-cm SCCVII tumors at 30 min before a single dose of 12 Gy or three fractions of 5 Gy at 12 h intervals. Changes of the hypoxic fraction (HF) were then evaluated by the paired survival curve method. Since the radiosensitizing effect of KU-2285 was relatively persistent, the HF was only evaluable after 6 h of irradiation. The HF of untreated SCCVII tumors was 9.1%. After treatment with KU-2285 and 12 Gy, the HF was 25% at 6 h, 32% at 12 h, 24% at 24 h, and 7.6% at 72 h. The HF was lower at 6 h than that after radiation alone, but was similar at later periods. After three fractions of 5 Gy with or without KU-2285, the HF was 33% at 6 h in both groups, while it was 12% and 13% at 24 h for tumors pretreated with KU-2285 and those receiving radiation alone, respectively. However, a sensitizing effect of KU-2285 was indicated by the downward shift of the survival curves for tumors irradiated after exposure to this agent. Reoxygenation occurred quite efficiently in tumors receiving KU-2285 and 12 Gy. After fractionated irradiation, however, reoxygenation was similar in the KU-2285-pretreatment and irradiation alone groups. 11 refs., 4 figs.

• OSTI ID: 6946443
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (United States), Journal Name: International Journal of Radiation Oncology, Biology and Physics; (United States) Vol. 29:3; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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