Three-dimensional volumetric analysis of irradiated lung with adjuvant breast irradiation.
OBJECTIVE
To retrospectively evaluate the dose-volume histogram data of irradiated lung in adjuvant breast radiotherapy (ABR) using a three-dimensional computed tomography (3D-CT)-guided planning technique; and to investigate the relationship between lung dose-volume data and traditionally used two-dimensional (2D) parameters, as well as their correlation with the incidence of steroid-requiring radiation pneumonitis (SRRP).


METHODS
Patients beginning ABR between January 2005 and February 2006 were retrospectively reviewed. Patients included were women aged >or=18 years with ductal carcinoma in situ or Stage I-III invasive carcinoma, who received radiotherapy using a 3D-CT technique to the breast or chest wall (two-field radiotherapy [2FRT]) with or without supraclavicular irradiation (three-field radiotherapy [3FRT]), to 50 Gy in 25 fractions. A 10-Gy tumor-bed boost was allowed. Lung dose-volume histogram parameters (V(10), V(20), V(30), V(40)), 2D parameters (central lung depth [CLD], maximum lung depth [MLD], and lung length [LL]), and incidence of SRRP were reported.


RESULTS
A total of 89 patients met the inclusion criteria: 51 had 2FRT, and 38 had 3FRT. With 2FRT, mean ipsilateral V(10), V(20), V(30), V(40) and CLD, MLD, LL were 20%, 14%, 11%, and 8% and 2.0 cm, 2.1 cm, and 14.6 cm, respectively, with strong correlation between CLD and ipsilateral V(10-V40) (R(2) = 0.73-0.83, p < 0.0005). With 3FRT, mean ipsilateral V(10), V(20), V(30), and V(40) were 30%, 22%, 17%, and 11%, but its correlation with 2D parameters was poor. With a median follow-up of 14.5 months, 1 case of SRRP was identified.


CONCLUSIONS
With only 1 case of SRRP observed, our study is limited in its ability to provide definitive guidance, but it does provide a starting point for acceptable lung irradiation during ABR. Further prospective studies are warranted.
Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
Amy Yuen Meei
AY
Teh
Eileen J H
EJ
Park
Liang
L
Shen
Hans T
HT
Chung
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D002278:Carcinoma in Situ / Q000473:pathology / Q000532:radiotherapy*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008168:Lung / Q000473:pathology / Q000528:radiation effects*; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000209:etiology; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D047368:Tumor Burden; D055815:Young Adult