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Hepatic Disorders: Colorectal Cancer Metastases, Cirrhosis and Hepatocellular
Carcinoma
II. Authors –
Brian C. Lucey, MD
Jose Varghese, MD
Jorge A. Soto, MD
All authors:
Department of Radiology
Boston University Medical Center
88 East Newton Street
Boston, MA 02118
(617) 638-6610 (voice)
(617) 638-6616 (fax)
Please address all correspondence to J.A.S. at above address
e-mail: Jorge.Soto@bmc.org
III. Issues
Issue 1: How accurate is imaging in patients with suspected hepatic metastatic disease?
Issue 2: What is the accuracy of imaging in patients with cirrhosis for the detection of
hepatocellular carcinoma?
Issue 3: What is the cost effectiveness of imaging in patients with suspected
hepatocellular carcinoma?
IV. Important points
-
State-of-the-art MR imaging may be superior to state-of-the-art multi-detector
CT for detection of liver metastases from colorectal cancer (insufficient
evidence. (limited evidence).
-
FDG-PET is the most sensitive non-invasive test for detecting liver metastases
(limited to moderate evidence)
-
Periodic screening with imaging tests of patients with cirrhosis for early
detection of hepatocellular carcinoma is beneficial (limited evidence)
-
MR imaging may be superior to CT for detecting hepatocellular carcinoma
(limited evidence).
X. Discussion of Issues
Issue 1 How accurate is imaging in patients with suspected hepatic metastatic
disease?
Summary:
CT and MR are the most widely used techniques for evaluating imaging the liver
in the initial staging and follow-up of cancer patients. For detecting liver metastases,
carefully performed CT and MR studies with state-of-the art equipment and interpretation
by experienced radiologists afford similarly good results. Some studies have showed a
slight advantage for MR (moderate evidence). Others, including a multi-institutional
study of 365 patients (moderate evidence), have not. CT is usually preferred because it is
more widely available and because it is a well established technique for surveying the
extrahepatic abdominal organs and tissues (such as the peritoneum and lymph nodes).
However, MR has an advantage in the characterization of focal lesions. Thus, MR is
commonly used as a problem solving tool or for initial staging of a tumor. MR is also
preferred for patients who cannot receive intravenous iodinated contrast material. Finally,
concerns about the risk of radiation from repeated exposure to CT examinations, makes
MR a valuable alternative for children or young adults with malignancies. As mentioned
previously, a comparison of the performance of CT vs. MR for this and other indications
needs to be reassessed periodically, considering the rapid evolution of both technologies
and the increase in therapeutic options available.
Kinkel et al reviewed a total of 111 studies that included over 3000 patients. At a
specificity of at least 85%, the weighted sensitivities were: US 55%, CT 72%, MR 76%
and PET 90% (Moderate Evidence). These data, however, need to be validated in
prospective trials before broad conclusions can be drawn. Intraoperative ultrasonography
(IOUS) has higher sensitivity than transabdominal ultrasonography, CT and MR.
The role of FDG PET and PET-CT will continue to expand, but cost constraints will limit
its use to patients in whom the possible impact is greatest.
Cirrhosis and Hepatocellular Carcinoma
Issue 2: What is the accuracy of imaging in patients with cirrhosis for the detection
of hepatocellular carcinoma?
Summary
Screening for HCC in patients with cirrhosis is not easy. No one imaging
modality dominates over the others. All imaging modalities have advantages and
disadvantages with no one modality offering both high sensitivity and specificity. The
results of these individual studies often depend on the date of the study. This is primarily
because of the rapid change in technology available in all imaging modalities. A
reasonable consensus for screening includes biannual measurement of the AFP level.
Annual sonography is the imaging modality most commonly used, as it is cheap, portable
and most widely available. If the AFP value increases and the sonogram does not show
evidence of an HCC, either CT or MR should be performed.
Although MR at present has marginally higher specificity than CT, the recent
improvement in CT technology may change this soon. Published sensitivities for MR
range from 48% to 87%. CT sensitivities for these studies range from 47% to 71 %
without the use of CTHA or CTAP. These reports conclude that MR is certainly as
sensitive and perhaps a little more so than CT. The use of super paramagnetic iron oxide
(SPIO) has increased the sensitivity of MR.
The sensitivity of sonography for detecting HCC has been reported between 5990%, with lower sensitivity for smaller lesions. Ultrasound may also lead to a high
percentage of false positive studies. Overall, there is little evidence to support the use of
PET imaging in the detection of HCC. The value of PET in this patient population lies in
detecting distant metastases and PET may be useful in monitoring the response to
treatment.
Issue 3
What is the cost effectiveness of imaging in patients with suspected hepatocellular
carcinoma?
Summary:
A study concluded that screening all patients with cirrhosis is of limited value given the
high cost and the benefit in terms of patient survival is poor. However, targeted
screening in high-risk patients with HCG and imaging may yet be of value.
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