Technical factors associated with radiation pneumonitis after local +/- regional radiation therapy for breast cancer.
OBJECTIVE
To assess the incidence of, and clinical factors associated with, symptomatic radiation pneumonitis (RP) after tangential breast/chest wall irradiation with or without regional lymph node treatment.


METHODS
The records of 613 patients irradiated with tangential photon fields for breast cancer with >6 months follow-up were reviewed. Clinically significant RP was defined as the presence of new pulmonary symptoms requiring steroids. Data on clinical factors previously reported to be associated with RP were collected, e.g., tamoxifen or chemotherapy exposure and age. The central lung distance (CLD) and the average of the superior and inferior mid lung distance (ALD) in the lateral tangential field were measured on simulator films as a surrogate for irradiated lung volume. Many patients were treated with partly wide tangential fields that included a heart block shielding a part of the lower lung.


RESULTS
RP developed in 15/613 (2.4%) patients. In the univariate analysis, there was an increased incidence of RP among patients treated with local-regional radiotherapy (RT) (4.1%) vs. those receiving local RT only (0.9%) (p = 0.02), and among patients receiving chemotherapy (3.9%) vs. those not treated with chemotherapy (1.4%) (p = 0.06). According to multivariate analysis, only the use of nodal RT remained independently associated with RP (p = 0.03). There was no statistically significant association between ranked CLD or ALD measurements and RP among patients treated with nodal irradiation with tangential beams. However, there was a statistically nonsignificant trend for increasing rates of RP with grouped ALD values: below 2 cm (4% RP rate), between 2 and 3 cm (6%), and above 3 cm (14%).


CONCLUSIONS
RP was an uncommon complication, both with local and local-regional RT. The addition of regional lymph node irradiation slightly increased the incidence of RP among patients treated with the partly wide tangential field technique. Concern for RP should, however, not deter patients with node-positive breast cancer from receiving local-regional RT.
Lind
Pehr A R M
PA
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Marks
Lawrence B
LB
Hardenbergh
Patricia H
PH
Clough
Robert
R
Fan
Ming
M
Hollis
Donna
D
Hernando
Maria Lourdes
ML
Lucas
Daniel
D
Piepgrass
Anna
A
Prosnitz
Leonard R
LR
D000704:Analysis of Variance; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy*; D002945:Cisplatin / Q000008:administration & dosage; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D015182:Lymphatic Irradiation; D008727:Methotrexate / Q000008:administration & dosage; D017564:Radiation Pneumonitis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D011859:Radiography; D012044:Regression Analysis
D002945:Cisplatin; D005472:Fluorouracil; D008727:Methotrexate