Alternate day treatment and late effects: the concept of an effective dose per fraction.
Int J Radiat Oncol Biol Phys
; 19(5): 1225-8, 1990 Nov.
Article
em En
| MEDLINE
| ID: mdl-2254117
ABSTRACT
Although most institutions treat all fields each day, some radiotherapists continue to adopt an alternate day schedule. The resulting daily variations of the dose per fraction in laterally located targets have been analyzed using the linear-quadratic model. Patients with breast carcinoma treated with definitive radiotherapy in 1974-1975 with one field a day were studied. An effective dose per fraction was derived, with a value higher than the average dose per fraction received by the reference point. The greater the fluctuations between the doses per fraction on successive days, the higher the effective dose per fraction. The corresponding cell survival due to alternate treatment as compared to survival with daily treatment depends on the alpha/beta ratio. For a late effect with low alpha/beta ratio, an alternate treatment may lead to almost 10-fold increase in cell kill in these lateral targets such as those responsible for subcutaneous sclerosis as compared to daily treatment of all fields with the same total dose. Taking the average effective dose per fraction in our series, the increase in cell kill was 4-fold. Acute effects would suffer less damage due to alternate treatment because of a high alpha/beta ratio. Treatment on an alternate schedule should be restricted to palliative radiotherapy.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dosagem Radioterapêutica
/
Neoplasias da Mama
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Female
/
Humans
País/Região como assunto:
Europa
Idioma:
En
Revista:
Int J Radiat Oncol Biol Phys
Ano de publicação:
1990
Tipo de documento:
Article
País de afiliação:
França