Changes in plasma transforming growth factor beta during radiotherapy and the risk of symptomatic radiation-induced pneumonitis.
OBJECTIVE
To determine whether changes in the plasma Transforming Growth Factor beta1 (TGF beta1) concentration during radiotherapy could identify patients at risk for developing symptomatic radiation pneumonitis.


METHODS
Thirty-six patients who received radiation therapy with curative intent for lung cancer (n = 31), Hodgkin's disease (n = 4), or thymoma (n = 1) were evaluated prospectively. All patients had serial plasma TGF beta1 measurements obtained before, during, and after treatment. Plasma TGF beta1 was quantified using an enzyme-linked immunosorbent assay. Pneumonitis was defined clinically. Plasma TGF beta1 levels were considered to have normalized if the following occurred: the last on-treatment TGF beta1 level was both <7.5 ng/ml and lower than the pretreatment level.


RESULTS
Thirteen of these 36 patients developed pneumonitis. Significant changes in plasma TGF beta1 levels during treatment were seen only in the subset of patients whose TGF beta1 levels were >7.5 ng/ml at baseline (n = 22). Failure of plasma TGF beta1 to normalize by the end of treatment, as defined above, much more accurately identified patients at risk for symptomatic pneumonitis if their baseline TGF beta1 was >7.5 ng/ml than if it was <7.5 ng/ml.


CONCLUSIONS
Changes in plasma TGF beta1 levels during radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic radiation pneumonitis, particularly in the subset of patients whose pretreatment TGF beta1 levels are >7.5 ng/ml.
Anscher
M S
MS
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Kong
F M
FM
Marks
L B
LB
Bentel
G C
GC
Jirtle
R L
RL
D015415:Biomarkers / Q000097:blood; D006689:Hodgkin Disease / Q000097:blood* / Q000532:radiotherapy; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000532:radiotherapy; D011446:Prospective Studies; D017564:Radiation Pneumonitis / Q000097:blood*; D012680:Sensitivity and Specificity; D013945:Thymoma / Q000097:blood* / Q000532:radiotherapy; D016212:Transforming Growth Factor beta / Q000097:blood*
D015415:Biomarkers; D016212:Transforming Growth Factor beta