Pulmonary injury and tumor response after stereotactic body radiotherapy (SBRT): results of a serial follow-up CT study.
OBJECTIVE
To evaluate the CT morphological pattern of tumor response and pulmonary injury after stereotactic body radiotherapy (SBRT) for early stage non-small lung cancer (NSCLC) and pulmonary metastases.


METHODS
Seventy patients (lesions n=86) with pulmonary metastases (n=48) or primary early stage NSCLC (n=38) were analyzed. Patients were treated with hypofractionated SBRT (three to eight fractions with a single dose between 6 and 12.5 Gy; n=56) or with radiosurgery (26 Gy; n=30). The pattern and sequence of pulmonary injury and of tumor response was evaluated in 346 follow-up CT studies, 4.9 on average.


RESULTS
Symptomatic pneumonitis was observed in 10% after a median interval of 5 months. No pulmonary reaction was observed in most patients 6 weeks after treatment; spotted-streaky condensations were characteristic between 3 months and 6 months. Dense consolidation and retraction started after 9 months and the fibrotic remodelling process continued for years. Ten targets relapsed after a median of 7 months. At 12 months complete response was seen in 43% and the differentiation of residual tumor from pulmonary reaction was not possible in 33%.


CONCLUSIONS
A typical sequence of pulmonary reactions was observed without differences between hypofractionated treatment and radiosurgery. Onset of pneumonitis was later compared to conventionally fractionated radiotherapy.
Department of Radiation Oncology, Julius-Maximilians University, Josef-Schneider-Strasse 11, Wuerzburg, Germany. guckenberger_m@klinik.uni-wuerzburg.de
Matthias
M
Guckenberger
Katrin
K
Heilman
Joern
J
Wulf
Gerd
G
Mueller
Gabriele
G
Beckmann
Michael
M
Flentje
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D008168:Lung / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome