Radiologist experience and CT examination quality determine metastasis detection in patients with esophageal or gastric cardia cancer
E. P. M. van Vliet J. J. Hermans W. De Wever M. J. C. Eijkemans E. W. Steyerberg C. Faasse E. P. M. van Helmond A. M. de Leeuw A. C. Sikkenk A. R. de Vries E. H. de Vries E. J. Kuipers P. D. Siersema
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W. De Wever Department of Radiology, University Hospitals Gasthuisberg
,
Leuven, Belgium
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J. J. Hermans Department of Radiology, Erasmus MC-University Medical Center Rotterdam
, P.O. Box 2040, 3000 CA Rotterdam,
The Netherlands
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Present address: P. D. Siersema Department of Gastroenterology and Hepatology, University Medical Center Utrecht
,
Utrecht, The Netherlands
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E. H. de Vries Department of Radiology, Vlietland Hospital
, Vlaardingen,
The Netherlands
4
A. R. de Vries Department of Radiology, Albert Schweitzer Hospital
, Dordrecht,
The Netherlands
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A. C. Sikkenk Department of Radiology, Medical Centre Rijnmond-South
, Rotterdam,
The Netherlands
6
A. M. de Leeuw Department of Radiology, Beatrix Hospital
, Gorinchem,
The Netherlands
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E. P. M. van Helmond Department of Radiology, Harbour Hospital
, Rotterdam,
The Netherlands
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C. Faasse Department of Radiology, Franciscus Hospital
, Roosendaal,
The Netherlands
We aimed to separate the influence of radiologist experience from that of CT quality in the evaluation of CT examinations of patients with esophageal or gastric cardia cancer. Two radiologists from referral centers ('expert radiologists')
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and six radiologists from regional
non-referral centers (non-expert
radiologists) performed 240 evaluations
of 72 CT examinations of patients
diagnosed with esophageal or gastric
cardia cancer between 1994 and 2003.
We used conditional logistic
regression analysis to calculate odds ratios
(OR) for the likelihood of a correct
diagnosis. Expert radiologists made a
correct diagnosis of the presence or
absence of distant metastases
according to the gold standard almost three
times more frequently (OR 2.9; 95%
CI 1.46.3) than non-expert
radiologists. For the subgroup of CT
examinations showing distant metastases, a
statistically significant correlation
(OR 3.5; 95% CI 1.49.1) was found
between CT quality as judged by the
radiologists and a correct diagnosis.
Both radiologist experience and
quality of the CT examination play a role
in the detection of distant metastases
in esophageal or gastric cardia cancer
patients. Therefore, we suggest that
staging procedures for esophageal and
gastric cardia cancer should preferably
be performed in centers with
technically advanced equipment and
experienced radiologists.
72 CT examinations
Fig. 1 Distribution of the CT examinations among the various
radiologists
72 CTs evaluated, 37 (51%) had distant metastases,
whereas the other 35 (49%) were without. Celiac lymph
node metastases were considered as regional (N1) if the
primary tumor was located in the gastric cardia and as
distant metastases (M1) if the tumor was located in the
esophagus. The gold standard was the postoperative
pathological TNM stage, the result of fine-needle
aspiration (FNA), or a radiological result with 6 months of
follow-up. In patients with the gold standard postoperative
pathological TNM stage or the result of FNA, no new
metastases were found in the 6 months following resection
or FNA, which suggests that the results of these gold
standards were reliable. None of the patients received
neoadjuvant therapy that could have changed the disease
status.
Table 1 Characteristics of CT examinations per group of 24 CTs
The distribution of CT examinations among the
participating radiologists is shown in Fig. 1. We made
three groups of 24 CT examinations. The two expert
radiologists evaluated 48 CTs, of which one set of 24 CT
examinations was evaluated by both expert radiologists to
determine the variability between these radiologists. The
six non-expert radiologists each evaluated 24 CTs. In order
to determine the variability between non-expert
radiologists, the 24 CTs in each group were evaluated by two
nonexpert radiologists. In summary, in group 1 and 3, 24 CTs
were evaluated by one expert and two non-expert
radiologists. In group 2, 24 CTs were evaluated by two
expert and two non-expert radiologists.
Each radiologist evaluated CT examinations from
regional centers and the referral center (Table 1). In
addition, each radiologist randomly evaluated two different
CTs of the same patient, meaning that the CT from the
regional center and that from the referral center were
evaluated by the same radiologist. In group 1, four CTs
from the regional center and four CTs from the referral
center performed in the same patients were evaluated by
the radiologists. In group 2, this number was 6 and in group
3, it was 5. Furthermore, each radiologist evaluated CTs
with metastases as well as CTs without metastases
according to the gold standard (Table 1).
CT examination quality was determined with four
criteria, which were given a score: (a) whether or not
intravenous contrast medium was administered (bolus
enhanced) (yes, 1; no, 2), (b) slice thic (...truncated)