Ozawa T, Faddegon BA, Hu LJ, Bollen AW, Lamborn KR, Deen DF. Response of intracerebral human glioblastoma xenografts to multifraction radiation exposures.
Int J Radiat Oncol Biol Phys 2006;
66:263-70. [PMID:
16904526 DOI:
10.1016/j.ijrobp.2006.05.010]
[Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 04/13/2006] [Accepted: 05/11/2006] [Indexed: 11/17/2022]
Abstract
PURPOSE
We investigated the effects of fractionated radiation treatments on the life spans of athymic rats bearing intracerebral brain tumors.
METHODS AND MATERIALS
U-251 MG or U-87 MG human glioblastoma cells were implanted into the brains of athymic rats, and the resulting tumors were irradiated once daily with various doses of ionizing radiation for 5 consecutive days or for 10 days with a 2-day break after Day 5.
RESULTS
Five daily doses of 1 and 1.5 Gy, and 10 doses of 0.75 and 1 Gy, cured some U-251 MG tumors. However, five daily doses of 0.5 Gy increased the survival time of animals bearing U-251 MG tumors 5 days without curing any animals of their tumors. Ten doses of 0.3 Gy given over 2 weeks extended the lifespan of the host animals 9 days without curing any animals. For U-87 MG tumors, 5 daily doses of 3 Gy produced an increased lifespan of 8 days without curing any animals, and 10 doses of 1 Gy prolonged lifespan 5.5 days without curing any animals. The differences in extension of life span between the 5- and 10-fraction protocols were minor for either tumor type.
CONCLUSION
The finding that the U-251 MG tumors are more sensitive than U-87 MG tumors, despite the fact that U-251 MG tumors contain many more hypoxic cells than U-87 MG tumors, suggests the intrinsic cellular radiosensitivities of these cell lines are more important than hypoxia in determining their in vivo radiosensitivities.
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