SIR-Spheres yttrium-90 radioembolization for the treatment of unresectable liver cancers

Abstract

Transarterial radioembolization with yttrium-90 resin microspheres (SIR-Spheres; Sirtex Medical Limited, Sydney, Australia) is a liver-directed therapy that is gaining recognition as a treatment option for liver-dominant primary and metastatic cancers. The incidence of complications is low and can be further reduced by patient selection and rigorous pretreatment assessment. Ideal candidates for radioembolization have preserved liver function without ascites or encephalopathy, Child-Pugh score <7 and limited lung shunting. Phase III randomized controlled trials (RCTs) against other liver-directed therapies are lacking for intermediate-stage hepatocellular carcinoma. However, preliminary data from a recent RCT has suggested that radioembolization has a similar time-to-progression and comparable toxicity to selective chemoembolization. Phase II/III RCTs are now ongoing to evaluate the combination of radioembolization with systemic therapies in advanced-stage hepatocellular carcinoma and metastatic liver-dominant colorectal cancer in order to expand the treatment opportunities for patients with cancers in the liver.

Keywords: colorectal cancer; hepatocellular carcinoma; liver metastases; neuroendocrine tumors; radioembolization; yttrium-90.

Figure 1.. ⁹⁰Y pretreatment planning.

(A) Arterial phase and (B) equilibrium phase computed tomography of residual hepatocellular carcinoma in VIII segment after a previous drug-eluting bead-based transarterial chemoembolization; (C & D) superselective angiography showing the positioning of the microcatheter for ⁹⁰Y-radioembolization treatment.

Figure 2.. ⁹⁰Y-pretreatment planning.

(A) Technetium-99m macroaggregated albumin planar scintigram for calculation of the degree of hepatopulmonary shunting: lung/liver ratio: 11.48%; (B) technetium-99m macroaggregated albumin single-photon emission computed tomography/computed tomography without any obvious collateral vessels and good differential distribution of particles between tumor and normal liver tissue (tumor to normal ratio).

Figure 3.. Imaging evaluation of ⁹⁰Y microsphere distribution.

(A) Pretreatment computed tomography and (B) PET/computed tomography of metastatic colorectal cancer of the liver performed immediately after radioembolization to check the distribution of ⁹⁰Y-radioembolization within the liver and to exclude any nontarget deposition of microspheres to other organs. Notice that the deposition of ⁹⁰Y-loaded microspheres corresponds with the sites of two large hepatocellular carcinoma lesions.

Figure 4.. Computed tomography showing perilesional rim enhancement at 1 month after a successful ⁹⁰Y-radioembolization.

(A) Arterial phase and (B) portal venous phase.

Figure 5.. Imaging pre- and post-treatment of a male (58 years of age) with hepatits C virus-related cirrhosis.

Pretreatment computed tomography demonstrates three hepatocellular carcinoma (HCC) lesions in segments: (A) VIII, (B) IV and (C) V (white arrows). (D) Dual super selective radioembolization was performed of the two lesions in segments VIII and V, with no treatment to the small HCC lesion in segment IV. Contrast-enhanced MRI study (gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid) at 3 months showing the hepatic fibrosis and capsular retraction of the treated segments VIII and V, appearing as wedge-shaped areas, hypervascular in the (E) arterial phase, (F) isointense in portal phase, with low signal intensity in the (G & H) hepatobiliary phase and the untreated small HCC lesions (see red arrows in E–H).

Figure 6.. Contralateral lobe hypertrophy.

Imaging (A) pre- and (B) 3 months post-radioembolization of a male (58 years of age) with a single metastatic colorectal cancer nodule in the right lobe observed after multiple lines of chemotherapy (FOLFOX and FOLFIRI) combined with wedge resections; (B) computed tomography 3 months after the treatment showed marked contralateral left lobe hypertrophy (similar to that achieved with right portal vein embolization), thereby predisposing to the safe hepatectomy of the right lobe; (C) computed tomography volumetric evaluation confirmed a 102% volume increase of the left lobe, from 750 cm³ at baseline to 1518 cm³.

Figure 7.. Hepatocellular carcinoma and portal vein thrombosis.

(A–C) Pretreatment CT scan of left lobe showing infiltrating hepatocellular carcinoma and left portal branch thrombosis (arrows) adjoining the portal confluence; (D–F) CT scan 3 months after ⁹⁰Y-radioembolization showing complete retraction of portal thrombus, marked left lobe shrinkage and almost undetectable hepatocellular carcinoma nodules.