Abstract

Radiation burden of hepatocellular carcinoma screening program in hepatitis B virus patients should we recommend magnetic resonance imaging instead?

Author(s): Ophelia Wong, Suong Le, Ronnie Ptasznik, Gideon Ptasznik & Mark Page*

Background: Current Hepatocellular Carcinoma (HCC) surveillance guidelines in high risk patients recommends characterization of a lesion detected on ultrasound with CT. Despite the superior diagnostic utility of MRI compared to CT, MRI is used as a problem solving tool after CT. Our aim was to assess the radiation burden of CT in a HCC screening program and assess the risk/benefit compared with MRI as the second step after ultrasound in a HCC screening program.

Methods: We conducted a retrospective cohort study of chronic hepatitis B (CHB) patients in a tertiary centre screening program from 2004 to 2014. Imaging modality, number of scans and radiation dose were calculated.

Findings: 382 CHB patients were engaged in an average 5 years of HCC surveillance. Those with 1-3 year follow up received a total dose per patient of 5 mSv, 4-6 years follow up received 11 mSv, >7 years follow up received 18 mSv of radiation. In the patients with over 7 years follow up the risk of radiation induced cancer was 1 in 850. Some patients had over 100 mSv resulting in radiation induced cancer risk of 1 in 146. 3 patients out of all 382 (0.79%) patients were diagnosed with HCC during surveillance. 99% of CTs were for false positive findings on ultrasound. Review of literature demonstrated better sensitivity and specificity for small HCC using MRI in addition to improved cost effectiveness of MRI in a screening program.

Conclusion: A significant number of CHB patients received multiple CT scans for false positive findings on ultrasound. Utilizing MRI instead of CT to further characterize US lesions has no radiation exposure and therefore no associated radiation induced cancer risk. Utilizing MRI instead of CT to further characterize US lesions has greater sensitivity and no radiation exposure compared to the current surveillance model.