Challenges in defining radiation pneumonitis in patients with lung cancer.
OBJECTIVE
To assess the difficulty of assigning a definitive clinical diagnosis of radiation (RT)-induced lung injury in patients irradiated for lung cancer.


METHODS
Between 1991 and 2003, 318 patients were enrolled in a prospective study to evaluate RT-induced lung injury. Only patients with lung cancer who had a longer than 6-month follow-up (251 patients) were considered in the current analysis. Of these, 47 of 251 patients had Grade >/=2 (treated with steroids) increasing shortness of breath after RT, thought possibly consistent with pneumonitis/fibrosis. The treating physician, and one to three additional reviewing physicians, evaluated the patients or their medical records, or both. The presence or absence of confounding clinical factors that made the diagnosis of RT-induced uncertain lung injury were recorded.


RESULTS
Thirty-one of 47 patients (66%) with shortness of breath had "classic" pneumonitis, i.e., they responded to steroids and had a definitive diagnosis of pneumonitis. In 13 of 47 patients (28%), the diagnosis of RT-induced toxicity was confounded by possible infection; exacerbation of preexisting lung disease (chronic obstructive pulmonary disease); tumor regrowth/progression; and cardiac disease in 6, 8, 5, and 1 patients, respectively (some of the patients had multiple confounding factors and were counted more than once). An additional 3 patients (6%) had progressive shortness of breath and an overall clinical course more consistent with fibrosis. All 3 had evidence of bronchial stenosis by bronchoscopy.


CONCLUSIONS
Scoring of radiation pneumonitis was challenging in 28% of patients treated for lung cancer owing to confounding medical conditions. Recognition of this uncertainty is needed and may limit our ability to understand RT-induced lung injury.
Kocak
Zafer
Z
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Evans
Elizabeth S
ES
Zhou
Su-Min
SM
Miller
Keith L
KL
Folz
Rodney J
RJ
Shafman
Timothy D
TD
Marks
Lawrence B
LB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004417:Dyspnea / Q000209:etiology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D017564:Radiation Pneumonitis / Q000150:complications / Q000175:diagnosis*