Liver Cancer Ultrasound Screening

Liver Cancer Ultrasound Screening Can Improve Survival of Cirrhosis Patients

By Medimaging International staff writers
Posted on 20 May 2014

Image: Dr. Amit Singal, assistant professor of internal medicine and clinical sciences at the University of Texas Southwestern Medical Center – author of the paper “Early Detection, Curative Treatment, and Survival Rates for Hepatocellular Carcinoma Surveillance in Patients with Cirrhosis: A Meta-analysis” published in the Public Library of Science Medical Journal (Photo courtesy of the University of Texas Southwestern Medical Center).

Liver cancer survival rates could be improved if more individuals with cirrhosis are screened for tumors using inexpensive ultrasound scanning and blood tests, according to a recent review.

The meta-analysis of 47 studies involving more than 15,000 patients discovered that the three-year survival rate was much higher among patients who received liver cancer screening—51% for patients who were screened compared to 28% of unscreened patients. The review also found that cirrhosis patients who were screened for liver cancer were more likely to receive curative treatment instead of palliative care.

“Curative therapies, such as surgery or a liver transplant, are only available if patients are found to have liver cancer at an early stage. Unfortunately, right now, only a minority of patients’ cancers are found at an early stage,” said Dr. Amit Singal, an assistant professor of internal medicine and clinical sciences at the University of Texas (UT) Southwestern Medical Center (Dallas, USA), and medical director of the Liver Tumor Clinic in the Harold C. Simmons Cancer Center.

Dr. Singal’s findings, published April 1, 2014, in the Public Library of Science Medical Journal, are especially significant for Texas because the state has high rates of fatty liver disease and hepatitis C, both of which are correlated with cirrhosis. Texas also has the second highest incidence of hepatocellular carcinoma (HCC), the most typical type of liver cancer in the United States. Many cases of HCC can be caught early with screening. “We have a simple test, an abdominal ultrasound which is painless and easy, but we found that less than 20% of at-risk people have the test done, largely due to providers failing to order it,” Dr. Singal said.

Dr. Singal reported that he hopes his study will encourage both patients and doctors to request ultrasound screening. He noted that liver cancer screening is not yet recommended by the US Preventative Services Task Force, partly because a randomized study has not yet been done, which points to a conundrum in the field. When a randomized study was attempted in 2005, many patients chose to leave the study when they heard evidence that liver cancer screening could be so beneficial. None of the patients wanted to be the ones randomly chosen to not get the tests.

Dr. Singal hopes his findings will convince more cirrhosis patients and their doctors that screening is worthwhile. “Just because we don’t have a randomized trial doesn’t mean there isn’t a benefit. We’re stuck in the middle ground where we’ve gone halfway. People are starting to believe liver cancer screening is helpful, but there’s not enough evidence to prove a definite benefit,” Dr. Singal said. “Part of our goal is providing evidence to both patients and physicians that liver cancer screening is beneficial.”

ARFI of NORMAL KIDNEY and HYDRONEPHROSIS in CHILDREN

Discussion

Hydronephrosis is an obstructive or non-obstructive nephropathy that is a commonly identified disease during pediatric abdominal ultrasonography. Congenital obstructive nephropathy constitutes the single most important identifiable cause of renal impairment in infants and children [10-12]. In obstructive nephropathy, interstitial fibrosis eventually develops and leads to a loss of nephrons [10].

Numerous papers that focus on the molecular biological mechanisms associated with renal interstitial fibrosis due to obstructive nephropathy have been recently published [10,13,14]. However, there is limited radiological research on renal interstitial fibrosis in the case of hydronephrosis. This could be attributed to the difficulty of detection, evaluation, and quantification of interstitial fibrosis by radiological methods.

There are many studies that explored ARFI measurements as a means of evaluating tissue stiffness, including several studies on kidneys. Gallotti et al. [6], Eiler et al. [7], and Goertz et al. [8] measured the ARFI velocities of normal kidneys in healthy adults.

Further, there have been several trials using ARFI in adult kidneys to evaluate renal masses, to assess renal allograft fibrosis, and to detect chronic kidney diseases [15-17]. However, there is a lack of studies involving ARFI measurements in young children. This could be attributed to the fact that the previously used low-frequency transducer is not effective in the case of such small patients.

However, the availability of the 4-9-MHz high-frequency linear transducer makes it possible to measure SWVs in small subjects. Recently, our group demonstrated normal values of SWVs using ARFI in pediatric abdominal organs including kidneys in 202 children with an average age of 8.1±4.7 years [1]. The mean SWVs were 2.19 m/sec for the right kidney and 2.33 m/sec for the left kidney in the above mentioned study. The previously reported mean SWVs in normal adult kidneys were 2.24-2.37 m/sec, with no significant difference between the right and the left kidney [6,8]. The median SWVs in normal kidneys in the present study were 1.75 m/sec without any difference between the right and the left ones. This value is relatively low as compared to that obtained in previous studies. However, this result is comparable with that of our previous study, which concluded that the mean ARFI SWV for the kidneys increased according to age in children less than 5 years of age [1].

In this study, we only included children under the age of 24 months. Only one study has been performed on the evaluation of diseased kidneys in children. Bruno et al. [5] conducted a study of ARFI measurements in pediatric patients with vesicoureteral reflux. The study suggested that ARFI can provide reliable information about the severity of renal damage and maybe useful in the diagnostic workup in children with a chronic reflux renal disease. However, the patient age in the study ranged from 8 to 16 years. Therefore, our study is the first report evaluating ARFI for hydronephrotic kidneys in young children.

We aimed to correlate SWVs with the hydronephrosis grade. Even though there are hydronephrosis grading systems on ultrasonography [11,18,19], these could not definitely differentiate between obstructive and non-obstructive hydronephrosis. Further, these systems cannot suggest the grade of renal parenchymal fibrosis. If SWVs have a correlation with the renal parenchymal stiffness, its measurement would be helpful in evaluating the status of a patient’s kidney. Further, SWV can show a continuous spectrum of stiffness.

On the other hand, the grading system has an ordinal scale that cannot show a continuous value. Therefore, elastography has a possibility of having an additional value to evaluate hydronephrosis. In our study, there was a significant difference in the median SWVs between normal kidneys (1.75 m/sec) and high-grade hydronephrotic kidneys (2.02 m/sec). This suggests that elasticity decreases and stiffness increases in high-grade hydronephrotic kidneys. However, ARFI measurements cannot differentiate the cause of stiffness change such as tissue fibrosis and edema. Further research with a large group of patients and pathologic correlation is needed.
We also compared SWVs for a hydronephrotic kidney with and without UPJO. Further, there were only seven patients proven to have UPJO during the study period. The mean ARFI velocities were 0.69-2.51 m/sec for hydronephrotic kidneys without UPJO and 1.54-2.72 m/sec for those with UPJO; there was no statistical difference. Kidneys with VUR and a parenchymal scar change also exhibited no remarkable difference in SWVs. This could be attributed to the small number of patients, variable interstitial fibrosis of the UPJO group, and heterogeneous parenchymal scar change in the refluxing kidneys. This needs further evaluation with a large number of patients.

This study has several limitations. Almost all previous studies performed in adults measured about 5-10 valid SWVs and used mean values. However, due to the characteristics of the pediatric patient group, only three valid SWVs were obtained in this study.

Repetitive measurements over a long time while subjects hold their breath is not possible in many children, particularly young children. Although only three valid ARFI velocities were attempted, two children could not tolerate the examinations and the success rate was 96%. Moreover, subjects were allowed to breathe freely during measurements. Thiscan increase the variability of SWV. The development of a method to measure SWV without breathholding would lead to more reliable results. 

The second limitation is the representativeness of the ARFI value.To represent a global kidney, measurement should be performed on multiple sites of the kidney, such as the upper, mid-, and lower poles. However, if the upper and lower poles are to be imaged, it is necessary to use a similar angle of incidence in all patients relative to the tubular system to avoid anisotropy issues. It is conceivable that shear waves generated within the kidney move at different velocities depending on the angle of incidence [20]. We tried to measure SWVs at the same portion of the mid-pole from the axial view, as parallel to the tubular system as possible in order to reduce the angle effect. The variation of the depth of the ROI position should also be considered.

We targeted renal parenchyma, including both the renal cortex and the medulla, from the axial view in each patient. Therefore, we might expect that the depth of the ROI position would be different between patients and could increase according to the body size. Further study is needed to evaluate the effect of the depth of the ROI position and the body size in children. 

The fourth limitation is that we considered the contralateral kidneys without hydronephrosis as normal in the hydronephrosis group. Even though we demonstrated no significant difference in SWVs between normal kidneys in the normal group and contralateral kidneys in the hydronephrosis group, there could have been a physiological change in the bilateral kidneys of the hydronephrosis group.

In conclusion, obtaining ARFI measurements of kidneys using a high-frequency transducer is feasible in very young pediatric patients. The median SWV of normal kidneys in children under the age of 24 months was 1.75 m/sec. These velocities increased in high-grade hydronephrotic kidneys but were not helpful in differentiating hydronephrotic kidneys with and without UPJO.

Beomseok Sohn; Myung-Joon Kim; Sang Won Han; Young Jae Im; Mi-Jung Lee.

AT MEDIC CENTER:

We applied ARFI technique from Siemens S2000 to evaluate whether fibrotic process existing in adult hydronephrosis.
Using 1-4 MHz convex probe we calculated in 3 positions of hydronephotic kidney due to  obstruction [stone, outside compression] (n=27 cases), due to ureteropelvic junction obstruction [UPJO] (n=30 cases]. We had a control group of normal kidney (n=36 cases).

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