Radiotherapy of the rhabdomyosarcoma R1H of the rat: the influence of the number of fractions on tumor and skin response

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(88)90266-0· OSTI ID:5170210

Wuerschmidt, F V; Vogler, H; Beck-Bornholdt, H P

The influence of the number of fractions on tumor and skin response to fractionated irradiation was studied. R1H rhabdomyosarcomas of the rat (volume doubling time 3 days) were irradiated with 6, 18, 30, or 42 fractions in 6 weeks. Total doses of 45, 60, or 75 Gy were applied in each fractionation scheme, that is, the dose per fraction ranged from 1.07 to 12.5 Gy. Tumor response was assessed by tumor control probability and tumor net growth delay. A clearcut reduction of skin damage was observed with increasing number of fractions, whereas the tumor response was found to be the same whether the dose was given in 6, 18, 30, or 42 fractions. Thus, the fractionation regimens were more effective than expected from calculations based on single-dose in situ survival curves. This result can be explained by assuming that the clonogenic tumor cells become less hypoxic with increasing number of fractions. Since normal tissue damage decreases with increasing number of fractions, the therapeutic gain may be improved by applying a greater number of fractions.

• Research Organization: Univ. of Hamburg (Germany, F.R.)
• OSTI ID: 5170210
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 14:3; ISSN IOBPD
• Country of Publication: United States
• Language: English

Related Subjects

550603* -- Medicine-- External Radiation in Therapy-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMAL CELLS
ANIMALS
BODY
DISEASES
DOSES
EXPERIMENTAL NEOPLASMS
FRACTIONATED IRRADIATION
IRRADIATION
MAMMALS
MEDICINE
MYOSARCOMAS
NEOPLASMS
NUCLEAR MEDICINE
ORGANS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
RATS
RHABDOMYOSARCOMAS
RODENTS
SARCOMAS
SKIN
SURVIVAL CURVES
THERAPY
TUMOR CELLS
VERTEBRATES