Lung dose-volume parameters and the risk of pneumonitis for patients treated with accelerated partial-breast irradiation using three-dimensional conformal radiotherapy.
OBJECTIVE
There are no data on how complication rates after accelerated partial-breast irradiation delivered by three-dimensional conformal radiotherapy are affected by treatment technique. We therefore examined the risk of pneumonitis in relation to lung dose-volume parameters.


METHODS
Our prospective dose-escalation trial enrolled 198 treated patients from 2003 to 2007. Patients received 32 or 36 Gy in 4-Gy fractions, given twice daily: 29 (14%) were treated with pure photons; 149 (77%) with mixed photons and electrons; and 20 (10%) with protons.


RESULTS
There were four cases of pneumonitis at 4, 4, 7, and 9 months after treatment. All were in the 36-Gy cohort and were treated with pure photons. The risk of pneumonitis for the two cohorts combined was: 17% (four of 24) for an ipsilateral lung volume (ILV) receiving 20 Gy or higher (ILV, 20 Gy) of 3% or higher (P = .0002 for comparison to ILV 20 Gy < 3%, Fisher's exact test); 20% (four of 20) for an ILV 10 Gy of 10% or higher (P = .0001); and 15% (four of 26) for an ILV 5 Gy of 20% or higher (P = .0002).


CONCLUSIONS
The risk of pneumonitis appeared related to the ILV treated. This volume can be reduced by using mixed photons and electron when possible. We recommend that the ILV 20 Gy should be lower than 3%, the ILV 10 Gy lower than 10%, and the ILV 5 Gy lower than 20% when purely coplanar techniques are used.
Recht
Abram
A
Beth Israel Deaconess Medical Center, Department of Radiation Oncology, Boston MA 02215, USA. arecht@bidmc.harvard.edu
Ancukiewicz
Marek
M
Alm El-Din
Mohamed A
MA
Lu
Xing-Qi
XQ
Martin
Chrystalla
C
Berman
Stuart M
SM
Hirsch
Ariel E
AE
Kachnic
Lisa A
LA
Katz
Angela
A
MacDonald
Shannon
S
Nedea
Elena A
EA
Stevenson
Mary Ann
MA
Powell
Simon N
SN
Taghian
Alphonse G
AG
D001940:Breast / Q000528:radiation effects*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008168:Lung / Q000528:radiation effects*; D008875:Middle Aged; D011014:Pneumonia / Q000209:etiology*; D011446:Prospective Studies; D011829:Radiation Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*