A team from Christchurch, New Zealand, determined the cause and clinicopathological factors associated with the failure of barium enemas to detect colorectal cancers.
A histopathological database was used to identify all patients with a diagnosis of colorectal cancer between 1991 and 1995.
These records were matched with the records from patients who underwent barium enema examinations between 1990 and 1995.
Those patients who had a colorectal cancer histologically diagnosed within 24 months of a barium enema, in which no carcinoma was seen, were identified. Where possible, the radiology was reviewed.
Failure to identify a carcinoma was then attributed to either simple failure, or to technical, interpretive, or perceptive difficulties.
There were a total of 967 patients with colorectal cancers treated in Christchurch Hospital during the study period between 1991 and 1995.
Matching of these patient details with all barium enema records revealed 313 patients who had barium enemas and histologically proven colorectal cancer.
The researchers found that there were 21 (7%) patients in whom a carcinoma was missed.
|7% of patients failed to have carcinoma detected by barium enema.
| Australian and New Zealand Journal of Surgery |
Of these, 18 had a barium enema within 8 months of surgery, and 3 were performed outside this time-span (15, 18, and 28 months, respectively).
On review, 11 carcinomas could not be identified (9 due to technical error: poor coating (n = 1), overlapping loops (n = 3), single-contrast enema (n = 4), fecal residue (n = 1)).
Seven of the carcinomas could be seen on review of the films (2 interpretation errors, 1 technical and perceptive error, and 4 perceptive errors).
In 3 cases, films could not be found for review.
In 16 of the 21 missed lesions, the patient had a double-contrast barium enema (DCBE), while 5 patients had single-contrast barium enema (SCBE).
Sharyn McDonald, of the Department of Radiology, Christchurch Hosptial, said on behalf of her colleagues, "The most common reason for missed tumors was technical error."
"The percentage of missed tumors in each region of the bowel correlates with the known incidence of tumors in each region and with a normal Dukes stage distribution.
"This did not include the cecum, where the number of missed lesions was higher than expected," she concluded.