Watershed hepatocellular carcinomas show lower rate of complete response to chemoembolization

"Watershed" hepatocellular carcinomas cross traditional Couinaud hepatic segment boundaries and can be challenging to treat with chemoembolization because they recruit arterial blood supply from multiple segments which can often be difficult to identify. The purpose of this single institution retrospective study was to evaluate complete response rates in watershed and nonwatershed HCCs following a single chemoembolization. One hundred fifty five treatment-naive patients with unresectable HCC that met Milan criteria (83 watershed lesions, 72 non watershed) were treated with superselective chemoembolization (conventional chemoembolization with doxorubicin/cisplatin or drug-eluting embolic agent with doxorubicin). DSA and cone-beam CT were used to identify arterial supply to the tumor prior to treatment. Eight to 12 weeks post embolization, patients were evaluated with cross-sectional imaging and treatment response was assessed using modified RECIST criteria. Complete response after single treatment with chemoembolization was seen in 55.4% of patients with watershed tumors and 72.2% patients with nonwatershed tumors. Watershed tumors with identifiable dual blood supply on cone beam CT showed a trend toward improved complete response rate (61% vs 53%). Disease free survival was longer in the nonwatershed group (336 days) compared to the watershed group (151 days).

Comment: 

Similar to prior studies, watershed tumors in this series were at higher risk of incomplete response following chemoembolization compared to HCCs within a single hepatic segment. In addition, this study suggests the use of cone-beam CT can be helpful to assess dual blood supply of watershed tumors. The interesting data presented suggest that patients with watershed patients should be monitored and treated more aggressively in order to bridge these patients to transplant.


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Images from a 63-year-old man with cirrhosis secondary to hepatitis C and a 2.2-cm HCC in segment IVa/VIII. (a, b) Contrast- enhanced cone-beam CT images demonstrate tumoral supply from segment IV (thick arrow, a), segment VIII (thin arrow, a), and segment III (arrowhead, b) arteries. (c, d) Selective catheterization and delivery of the chemoembolic emulsion was performed via segment IV (c, arrow), segment VIII (d, arrow), and segment III (not shown). Circumferential uptake of the chemoembolic emulsion was confirmed on digital imaging during selective catheterization and by an unenhanced cone-beam CT acquisition at completion (e). (f) Contrast-enhanced, multiphasic MR image obtained at 6 weeks following chemoembolization demonstrates enhancement of the previously treated tumor.


Citation: Kothary, N. et al. Watershed Hepatocellular Carcinomas: The Risk of Incomplete Response following Transhepatic Arterial Chemoembolization. Journal of Vascular and Interventional Radiology 26, 1122–1129 (2015).


Post author: Menaka Nadar, MD. VIR Pathway Resident at University of Virginia