Repeat 90Y-microsphere radioembolization for hepatic malignancies: Safety and patient selection issues

Abstract

15177 Background: Liver tolerance to reirradiation with multiple doses of 90Y-microspheres is not known. Many patients (pts) have also received external beam radiotherapy to the liver or through the liver and are surviving long enough to be considered for a second and third liver treatments with internal radiation. Methods: The experience of a single center treating liver tumors with resin 90Y-microspheres was used. Pts that received liver radiation prior to or after resin microsphere therapy were studied. Endpoints were toxicity, tumor response, disease type, latency period between radiation treatments, shunting to lung, and effects on liver volume and function. The delivery activity of microspheres selected was not reduced below that which was typically chosen for patients without prior liver radiation which was 25% reduced from the manufacturer’s BSA dose calculation method. All patients received bilobar microsphere delivery during a single session. Results: A total of 40 pts were identified; 14 women, 26 men, treated 6/2003 to 12/2006, with 35 pts receiving 2 courses and 5 pts with 3 courses of liver radiation. Retreatment with resin microspheres 26 pts, prior external beam radiation in 7 pts, prior glass microspheres in 2pts, prior systemic radiotherapy in 2 pts, and prior stereotactic liver radiation in 1 pt. Liver function was stable and adequate in all patients after additional liver radiation, and no pts developed radiation-induced liver dysfunction (RILD) or veno-occlusive disease (VOD). The percentage of shunting to the lung decreased with retreatment. Tumors treated: 14 carcinoid, 11 colorectal, 6 hepatocellular and cholangiocarcinoma, 2 sarcoma, 3 unknown primary, 1 each of breast, esophagus, and head and neck primaries. Conclusions: Repeated radiation to the liver with 90Y-microspheres appears safe in patients that have sufficient normal liver function and reserve based on known laboratory parameters already used for selection of microsphere therapy. No acute life-threatening, fatal, or late liver damage was observed, i.e. RILD or VOD. No specific dose reduction is recommended for retreatment of the liver. No significant financial relationships to disclose.