DISCUSSION

To our knowledge, we are the first to evaluate the use of follow-up chest CT in the surveillance of HCC patients. The results of the present study confirmed our hypothesis that follow-up chest CT is of limited value in the surveillance of HCC patients. Only 3% of our patient population had disease progression in the chest without corresponding progression in the liver or abdomen on follow-up CT. Furthermore, only 2.2% of the patients who had a negative baseline chest CT examination had disease progression in the chest without a corresponding progression in the liver or abdomen on follow-up CT.

Others have assessed the incidence of extrahepatic disease burden in HCC patients. Leong et al reported that lung is the most common site of extrahepatic spread of HCC and that its incidence infrequent (12.6%).¹⁰ Kanda et al reported that the lifetime annual incidence rate of extrahepatic metastasis is approximately 2.5%. The reported incidence of extrahepatic metastasis is as high as 19.5% at 7 years.⁸ Jin et al, evaluating the role of chest CT in the staging workup of HCC patients, found that 2.9% of patients had metastatic disease in the chest but not the liver.¹¹ Others have also reported a limited role of the chest CT examination in HCC patients.^12,13 These reports did not correlate the disease progression in the abdomen with the progression of the disease in the chest.^7,9–12

In the present study, baseline CT revealed a prevalence (76/226; 33.6%) of extrahepatic metastatic disease at baseline. The incidence of extrahepatic disease in the present study (33.6%) was larger than that reported previously.^7,9–12 This may have been because our study was conducted at a tertiary cancer center, whose patients tend to have more advanced disease.

Follow-up CT revealed that 38 patients had progression in the chest and that 31 of these 38 patients had corresponding progression in the abdomen. These findings suggest that abdominal CT alone should be sufficient to detect disease progression in most patients.

Our study had some limitations. We extracted data from the original radiology reports, not from a second review of the CT examinations. However, extraction of data from radiology reports approximates the clinical practice for making treatment and other clinical decisions. We did not stratify the patients according to their clinical disease stage, tumor burden, or tumor size. It may seem possible to consider that advanced stage and increased tumor burned may result in higher incidence of disease progression. However, we expect to see the progression in the abdomen and not chest-only disease progression. The very low incidence of chest only progression with a negative baseline CT will probably remain small. Another limitation was that the time lapse between the patients’ baseline CT and follow-up CT examinations were relatively short. However, we found that some patients had disease progression as few as 6 weeks after baseline CT. Although a longer follow-up period could yield more disease burden, we expect to be present in the liver and extrahepatic, and not chest-only disease progression. Finally, a substantial portion of our patient population had a high disease burden. When extended to the larger population with less disease burden, we anticipate a lower incidence of extrahepatic disease and/or chest-only progression and anticipate a smaller percentage of chest only progression.

Value of Follow-Up Chest Computed Tomography in the Surveillance of Patients with Hepatocellular Carcinoma

DISCUSSION

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