Hepatocellular cancer: what if the AFP is rising but no lesion seen on imaging? Arun J Sanyal M.B.B.S., M.D. Charles Caravati Professor of Medicine Virginia Commonwealth University Imaging features used to diagnose HCC Presence of a visible mass with or without involvement of blood vessels etc Changes seen over time after injection of an intravenous contrast agent Tissue characteristics based on its content CONFLICTS: US principal investigator for treatment trial of HCC-Gideon (BAYER) What if the AFP is rising but no lesion seen? HCC and mass effect AFP is coming from outside the liver The imaging technique is incorrect HCC present but imaging unable to detect Rise in AFP due to regenerative activity Small:tumors < 2 cm in diameter Nodular: single or multiple discrete nodules (2-5 cm) Massive: > 5 cm with or without satellite lesions Diffuse: multiple minute indistinct nodules What you need to know about AFP Size matters Normally produced in the fetus-fetal equivalent of albumin Elevated levels occurs due to: Neonatal period Pregnancy Pregnancy-related disorders (omphalocele) Germ cell tumors (testes and ovary) Hepatocellular carcinoma Hepatic regenerative activity Type of lesion Regenerative nodule Low grade dysplastic nodule High grade dysplastic nodule Well differentiated HCC Classic HCC Mean size (cm) < 1 1 1.3 1.6 2.2 Matsui O. CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2005;3:S136 S140 1
Phases of blood flow in the liver HCC: CT scan imaging Precontrast Arterial peak Venous peak washout 0 5-20 60-90 200-300 seconds Pre-contrast arterial venous Regenerative nodule Characteristic features of HCC on contrast imaging Main blood supply from portal vein Mild arterial enhancement Strong venous enhancement Courtesy of Claude Sirlin M.D., UCSD Hepatocellular cancer Additional MRI features of HCC Hepatic artery and portal vein supply lost Arterial neovascularization Early enhancement Washout in venous/delayed phase Variable intensity on T1-image Hyperintensity on T2-image 2
Imaging criteria for diagnosis of HCC Diffuse hepatocellular cancer Finding Sensitivity Specificity Arterial enhancement > 90% 80% Delayed washout Delayed enhancing capsule Bright lesion on T2 images 80% 89% 80% 95% 96% 95% Bright lesion in T2 weighted image Arterial enhancement with malignant Portal vein thrombosis Multiple sources Willat et al, Radiology, 2008, 247: 311-330 Utility of imaging modalities for diagnosis of HCC Confluent scar vs tumor: progressive enhancement in scar Modality Sensitivity Specificity Conventional US 45-92% 40-90% Contrast-enhanced US CT scan MRI 60-90% 68% 81% > 90% > 95% > 95% Multiple sources AFP elevated but imaging inconclusive No lesion identified: HCC in very early stage of development small HCC (< 2 cm in diameter) diffuse HCC seen difficult to characterize: small lesions (< 2 cm) dysplastic nodule infarction (with regenerative activity making AFP rise) Alternate cause of high AFP: regenerative activity non-hepatic source (germ cell tumors) Approach to elevated AFP without diagnostic imaging Ensure correct technique is used Repeat imaging to leverage differences in doubling time Use 2 modalities to improve diagnostic accuracy Additional biomarkers Use additional technology 3
Very small HCC: diagnosis with MRI Similar findings on two modalities allow HCC diagnosis to be made with high specificity N= 89 Nodules 1-2 cm in size in cirrhotic subjects Modality sensitivity specificity PPV NPV CEUS 62 96 97 55 MRI 52 93 94 50 CEUS + MRI 33 100 100 42 Forner et al, HEPATOLOGY 2008;47:97-104 Malignant tumors grow faster than benign tumors Doubling time Malignant tumors: Median doubling time 120-180 days Benign tumors: > 1 yr Alternate biomarkers AFP-L3 (lectin-bound AFP), descarboxylprothrombin (DCP), glypican-3 Relevant only when AFP > 10 or < 200 If AFP-L3 > 10%, then: sensitivity: 70% specificity: 63% If AFP-L3 > 35%, then: sensitivity: 33% specificity: 100% Taouli et al J Comput Assist Tomogr 2005;29:425 429 Benign nodule masquerading as cancer: arterial enhancement without washout Natural history of HCC development Pre contrast Arterial phase Venous phase Delayed phase Matsui et al, Clin Gastroenterol Hepatol, 2005, 3:S136-S140 4
Dysplastic nodules Super-paramegnetic iron oxide (SPIO)-MRI Isointense on T1 and T2 like regenerative nodules Low grade dysplasia: retain portal vein supply High grade dysplasia: increasing arterial enhancement and decreased venous enhancement T2 image bright if infarcted Nodule within nodule Fe is taken up by Kupffer cells and make the liver look darker and making the tumor which lacks Kupffer cells stand out as a bright signal Macarini et al, Radiol med (2009) 114:1267 1282 CT scan during arterial or venous angiography Is PET scanning useful? CTAP CTAH T2 weighted MRI MRI with gadopentate FDG-PET of same lesion Portal supply intact decreased arterial supply CT arterial portography (CTAP): evaluates portal supply of lesion CT hepatic arteriography (CTHA): evaluates arterial attenuation of lesion PET: False negative rates of 40-50% CT-arteriography for diagnosis of very small or indeterminate nodules Nuclear medicine fusion study Contrast-CT scan Octreotide-SPECT +CT scan Pattern Findings correlate I Nodule not seen, arterial and venous supply Low grade intact Dysplasia II Nodule hypodense-indicating decrease in arterial supply High grade Dysplasia III IV Partial Hyperdense area in a nodule (neoarterialization) + loss of portal supply Diffusely hyperdense lesion with loss of portal supply Early HCC in a nodule Classic HCC Outwater et al, Cancer Control, April 2010 5
A suggested algorithm for management Repeat Imaging + labs 3 months High AFP, imaging inconclusive Perform contrast imaging (CEUS, CT or MRI) HIGH RISK SUBJECT High AFP Multiple risk factors Use 2 nd modality CTA?AFP-L3 REFER TO A TRANSPLANT CENTER EARLY confirmed No YES MODERATE RISK SUBJECT Modest AFP, cirrhosis Indeterminate Not seen seen AFP-L3 Use 2 nd modality AFP-L3 confirmed YES No Repeat Imaging + labs 3 months THANK YOU FOR YOUR ATTENTION 6