Radiology, Vol 121, 709-715, Copyright © 1976 by Radiological Society of North America
Prospective studies with the CRE formula of prolonged fractionation schedules
G Notter and I Turesson
Different dose schedules prospectively calculated with the Cumulative
Radiation Effect (CRE) formula were used for irradiation of inoperable
breast carcinomas. Fractionation with 2 X 260 rad and 2 X 450 rad twice a
week, and total doses corresponding to CRE levels 1900 to 2300, were
compared. The results showed that prolonged fractionation increased the
tolerance of normal skin and the therapeutic ration with respect to early
radiation reactions. Late reactions could not be assessed as yet because
their development requires several years. With the prolonged course of
treatment and 2 X 260 rad per week, no moist desquamation developed despite
dose levels between 6800 and 9400 rad. Skin reactions were milder than
those in the rapidly treated areas, indicating that the CRE formula cannot
exactly predict acute skin reactions for very prolonged treatment
schedules. The tumor regressed continuously during the irradiation
schedule.
