Acute radiation pneumonitis after postmastectomy irradiation: effect of fraction size.
Prior to 1982 the standard radiation tissue absorbed dose administered to the chest wall following mastectomy was 40.0-42.5 Gy in 10 alternate day fractions over 4 weeks. From 1982 the standard maximum dose was 45.0 Gy administered in 20 daily fractions over 4 weeks. On review of the records of the 770 patients treated between 1979 and 1984, 19 (2.5%) had symptoms of acute radiation pneumonitis, 7/484 (1.4%) treated by the earlier technique and 12/286 (4.2%) by the later technique (X2 = 4.56, P less than 0.05). The mean 4 cm depth doses on the chest wall were 33.98 Gy and 36.84 Gy respectively in the earlier and later populations (t = 5.06, P less than 0.001) and 33.62 Gy and 38.30 Gy in those developing acute pneumonitis. Comparison of these two schedules gives an alpha/beta ratio of 8.5 Gy. It is suggested that the sparing of symptomatic acute reactions in human lung by smaller doses per fraction may be less than currently believed.
Price
A
A
Department of Clinical Oncology, Western General Hospital, Edinburgh, Scotland, UK.
Jack
W J
WJ
Kerr
G R
GR
Rodger
A
A
D000208:Acute Disease; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008408:Mastectomy; D011014:Pneumonia / Q000209:etiology*; D011832:Radiation Injuries; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage