Lung cancers missed at low-dose helical CT screening in a general population: comparison of clinical, histopathologic, and imaging findings.
OBJECTIVE
To compare clinical, histopathologic, and imaging features of lung cancers missed at low-radiation-dose helical computed tomography (CT).


METHODS
Eighty-three primary lung cancers were found during an annual low-dose CT screening program and confirmed histopathologically at either surgery or biopsy. Thirty-two of these lung cancers were missed on 39 CT scans: on 23 scans owing to detection errors and on 16 owing to interpretation errors. The clinical characteristics, CT features, and histopathologic findings of these missed lung cancers were correlated.


RESULTS
All missed cancers were intrapulmonary, and 28 (88%) were stage IA. All 20 detection errors occurred in cases of adenocarcinoma, 17 (85%) of which were well-differentiated tumors and 11 (55%) of which were in nonsmoking women. The mean size of cancers missed owing to detection error, 9.8 mm, was smaller than that of cancers missed owing to interpretation error, 15.9 mm (P <.001). In the detection error group, the percentages of nodules with ground-glass opacity (91%) or judged to be subtle (91%) were greater than those of nodules in the interpretation error group (38% and 25%, respectively) (P <.001). In the detection error group, 83% (19/23) of cancers were overlapped with, obscured by, or similar in appearance to normal structures such as pulmonary vessels. On 14 of the 16 CT scans with which there were interpretation errors, the CT findings mimicked benign disease, and the patients also had underlying lung disease, such as tuberculosis, emphysema, or lung fibrosis.


CONCLUSIONS
The lung cancers missed at low-dose CT screening in this series generally were very subtle and appeared as small faint nodules, overlapping normal structures, or opacities in a complex background of other disease.
Li
Feng
F
Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, MC-2026, University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637, USA. fli@kurt.bsd.uchicago.edu
Sone
Shusuke
S
Abe
Hiroyuki
H
MacMahon
Heber
H
Armato
Samuel G
SG
Doi
Kunio
K
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000453:epidemiology; D000368:Aged; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011829:Radiation Dosage; D012307:Risk Factors; D036542:Tomography, Spiral Computed