Accuracy of Endoscopic Ultrasound for Detection of Tumors of the Liver – A Prospective Study
The incidence of hepatocellular carcinoma is increasing in US. The reason for this increase
has been attributed to the emergence of hepatitis C. Studies suggest that patients with
hepatitis C are at higher risk of developing hepatocellular carcinoma (elevated
alpha-fetoprotein) and, therefore should undergo periodic radiological investigation.
The liver is also a common site for metastases for various malignancies. The metastasis to
liver profoundly affects the management and prognosis, since these patients have advanced
cancer and therefore are not candidates for surgery.
1.1 Current standards of care
For primary liver tumors alpha-fetoprotein, abdominal ultrasound and CT scan of the abdomen
are the suggested tests for the screening in patients that are at higher risk of developing
this complication. Measurement of serum alpha-fetoprotein (AFP) may be helpful in the
diagnosis and management of HCC. AFP is elevated above 20 ng/Ml in more than 70% of patients
with HCC. However, AFP elevations from 10-500 ng/Ml and even occasionally to 1000 ng/ml may
be seen in patients with a high degree of inflammatory activity such as with chronic viral
hepatitis, who do not have HCC (3). The sensitivity, specificity, and positive predictive
value of AFP in 3 well performed screening studies for HCC ranged from 39%-64%, 76%-91%, and
9%-32%, respectively (4). Imaging studies play a key role in the diagnosis of HCC since a
significant number of cases are missed by AFP. CT scan and magnetic resonance imaging are
commonly used tests.
On the basis of studies conducted over last two decades, National Comprehensive Cancer
Network (2004) guidelines for the management of cancer recommended CT scan for the
evaluation of the liver for metastases (Please refer to appendix III).
Recent studies have shown that CT scan is far from ideal for detection of primary as well as
metastases to liver (5,6). A well designed study showed that CT scan missed 32 % of the
primary tumors of the liver. A prospective study of 100 patients with colorectal cancer
showed that CT scan missed liver metastases in 37% of cases (5). Another prospective
controlled study of 135 subjects showed that CT scan failed to detect liver metastases in
49% of patients with various malignancies (6).
1.2 EUS as a possible diagnostic tool for liver tumors EUS is a well-established tool for
the diagnosis and/ or staging of the esophageal, gastric and pancreatic cancer. Recent
studies have shown a potential role of EUS for the liver imaging (7, 8, and 9).
1.3 Comparison of EUS and CT scan for detection of liver metastases
Studies suggest that EUS may be an attractive alternative to CT scan for detection of the
liver metastases, since it can detect lesions that are missed on the CT scan (9). EUS
detected metastatic lesions overlooked by conventional, cross-sectional imaging studies in 5
of 222 cases (2.3%) (9). Another study found occult liver metastases in 2.4% of 574 patients
with suspected GI or pulmonary malignancies (4). Each patient found to have occult
metastases at EUS had staging CT, which raises an issue as to the quality and/or
interpretation of those studies.
An additional advantage of EUS is that fine needle aspiration (FNA) can be performed
simultaneously and therefore confirmation of malignancy can usually be accomplished in a
single procedure whereas CT or US typically require 2 sessions to accomplish these tasks,
one for detection and another for FNA.
1.4 Limitation of EUS: Right lobe The limitation of the EUS is that it is not able to
examine the right lobe of the liver completely.
1.5 Rationale for the study. The diagnostic accuracy of EUS for detection of the liver
tumors (primary and metastatic) remains unknown. There is sufficient evidence to suggest
that EUS may be superior to the CT scan for the liver metastases. Studies that have
evaluated the role of EUS are limited by small sample size or retrospective design.
Therefore, a prospective study with adequate sample size is required to determine the
diagnostic accuracy of endoscopy ultrasound.
To compare the accuracy of the EUS and CT scan for detection of the primary and metastatic
carcinoma of the liver.
2.2 Secondary: 2.2.1 Determine the diagnostic yield of fine needle aspiration using EUS
(EUS-FNA) in patients with suspected liver metastasis on EUS examination.
2.2.2 Compare the accuracy of the PET scan with EUS for the detection of the liver
2.2.3 Determine the safety of EUS-FNA in subjects with liver lesions. 2.2.4 Impact of the
EUS on the management of the hepatocellular carcinoma 2.2.5 To study characteristic
echoendoscopic findings of the primary and secondary liver tumor.
2.3 Hypothesis: 2.3.1 EUS is likely to detect primary tumor and liver metastasis in subjects
with normal CT scan.
3.0 Design: This is a prospective study where study group would comprise of consecutive
patients with newly diagnosed colon, pancreatic, esophageal, lung, gastric cancer and
patient with hepatitis C or B with elevated levels of alpha-fetoprotein or radiological
findings suggestive of mass in the liver.
Patients would be selected from gastroenterology clinic, primary care clinic, surgery
clinic, sub-specialty clinics (Oncology, Pulmonary) and hepatitis C clinic. These clinics
would be informed about the ongoing EUS study and the eligibility criteria’s of the study.
All patients will be seen in the gastroenterology clinic where a detail description of the
EUS-FNA procedure would be provided to them. In addition, patients would be provided consent
forms. (Please refer to section 5 for details of the consent process.)
Enrollment of participants.
Patients enrolled in the study would undergo -
- Detailed history and physical examination,
- CT-abdomen preferably with contrast, and
- Possible PET scan. PET scan will be performed on patients who do not have evident
- Intervention allocation: all eligible patients would be encouraged to undergo EUS and
Description and schedule: All eligible patients would undergo EUS examination of the liver.
Any subject with abnormality suspicious for malignancy in liver would undergo FNA.
Follow-up visits description and schedule. After the procedure patient would be referred
back to the clinic from which the patient was identified for further management. These
patients are usually seen by oncologists, pulmonologists and cardio-thoracic surgeon
depending on the stage and the medical condition of the patient.
Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
To compare the accuracy of the EUS and CT scan for detection of the primary and metastatic carcinoma of the liver.
Pankaj Singh, MD
Central Texas Veterans Health Care System
United States: Institutional Review Board
|Central Texas Veterans Health Care System||Temple, Texas 76504|