Plasma transforming growth factor beta1 as a predictor of radiation pneumonitis.
OBJECTIVE
To investigate prospectively the utility of plasma transforming growth factor beta1 (TGFbeta1) as a marker for the development of symptomatic radiation pneumonitis.


METHODS
Seventy-three patients with lung cancer treated with curative intent are reported herein. Plasma TGFbeta1 samples were obtained before, weekly during, and at each follow-up after radiation therapy (RT). TGFbeta1 was extracted using an acid/ethanol method. An enzyme-linked immunosorbent assay was used to quantify plasma TGFbeta1 concentrations. The TGFbeta1 level at the end of RT was considered "normal" if it was both < or = 7.5 ng/ml and less than the pretreatment value. All patients were followed for at least 6 months, unless symptomatic pneumonitis developed sooner. Pneumonitis was defined by National Cancer Institute (NCI) common toxicity criteria.


RESULTS
Fifteen of the 73 patients (21%) developed symptomatic pneumonitis and the remaining 58 (79%) did not. A normal plasma TGFbeta1 by the end of RT, as defined above, was more common in patients who did not develop pneumonitis. A return of the plasma TGFbeta1 to normal accurately identified patients who would not develop pneumonitis with both a sensitivity and positive predictive value of 90%.


CONCLUSIONS
Plasma TGFbeta1 levels appear to be a useful means to identify patients at low risk for the development of pneumonitis from thoracic RT. Thus, monitoring of plasma TGFbeta1 levels may identify candidates for dose escalation studies in the treatment of lung cancer.
Department of Radiation Oncology, Duke Comprehensive Cancer Center, Duke University Medical Center, Durham, North Carolina 27710, USA.
M S
MS
Anscher
F M
FM
Kong
K
K
Andrews
R
R
Clough
L B
LB
Marks
G
G
Bentel
R L
RL
Jirtle
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017564:Radiation Pneumonitis / Q000097:blood / Q000175:diagnosis*; D016212:Transforming Growth Factor beta / Q000097:blood*
D015415:Biomarkers; D016212:Transforming Growth Factor beta