BACKGROUND AND PURPOSE: In clinical practice a concomitant boost is usually given as a second daily dose to a reduced field. The question arises which part of treatment should be accelerated to achieve @entity5 control. An experiment was performed on @entity5 bearing @entity35 to determine the optimal timing of treatment acceleration for this experimental @entity5 system. MATERIAL AND METHODS: @entity980 R1H of the @entity35 were treated applying 30 fractions in an overall treatment time of 40-42 days, up to total doses ranging from 67.5 to 97.5 Gy were administered. For control a standard treatment was given as continuous treatment applying one fraction per day. A boost of five additional fractions was given as a second fraction during 5 days. Three experimental arms received a boost either in the 1st, 4th, or in the last week of treatment. Treatment outcome was assessed using @entity5 control as endpoint. RESULTS: All experimental arms proved more effective than the standard treatment. Treatment was most effective when the boost was administered in the 1st week of treatment. A TCD37% of 87.1 Gy (95% CI: 82.8 ... 92.7 Gy), 96.5 Gy (89.9 ... 107.1), and 107.3 Gy (97.2 ... 131.0) was determined, when the boost was given in the 1st, 4th, or last week of treatment, respectively. The observed difference between the experimental arms was statistically significant (p = 0.004). CONCLUSIONS: Initially accelerated treatment schedules were found to be more effective for @entity5 control in an experimental @entity5 system.

Impact of treatment acceleration and its timing on the response of the @entity980 R1H of the XXXX to fractionated irradiation.

@entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'optimal tumor'] @entity980 :: ('MESH:D012208', 'Disease') :: ['Rhabdomyosarcoma'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats']
@entity35 :: (10116,Species) :: ['rat']
