Incidental detection of colon cancer by FDG positron emission tomography in patients examined for pulmonary nodules.
OBJECTIVE
Fluorodeoxyglucose (FDG) positron emission tomographic (PET) imaging has been used extensively to diagnose cancer with high rates of sensitivity and specificity. One of its applications is to distinguish benign from malignant pulmonary nodules. It is common to observe colonic uptake on whole-body FDG-PET images. Because patients with lung cancer also tend to be in the age group with the highest incidence of colon cancer, the authors tried to assess the efficacy of FDG-PET for detecting occult colon cancer in patients referred for the evaluation of lung nodules.


METHODS
The records of 500 consecutive patients referred for the evaluation of pulmonary nodules were reviewed retrospectively. Among the patients, 197 had no previous clinical or radiographic evidence of abnormalities in the gastrointestinal tract, and none had been found to have any cancer before undergoing an FDG-PET study. All colon lesions were verified either by histologic analysis or by clinical course.


RESULTS
Among the 197 patients analyzed, 59 had diffuse colonic uptake in various segments of the colon. Seventeen of the patients had focal colonic uptake, five of which were proved to be colon cancer.


CONCLUSIONS
The routine use of FDG PET to characterize lung lesions significantly increases the probability of detecting unexpected extrathoracic disease. In these patients, the incidental finding of colon cancer had an important effect on their treatment and may prove to be very cost-effective.
Division of Nuclear Medicine, Department of Radiology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Hongming
H
Zhuang
Marc
M
Hickeson
Thomas K
TK
Chacko
Paulo S
PS
Duarte
Khozaim Z
KZ
Nakhoda
Qi
Q
Feng
Abass
A
Alavi
D000230:Adenocarcinoma / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D000236:Adenoma / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D001706:Biopsy; D003110:Colonic Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D003113:Colonoscopy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012812:Sigmoidoscopy; D003074:Solitary Pulmonary Nodule / Q000150:complications / Q000000981:diagnostic imaging*; D014055:Tomography, Emission-Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18