(P102) Effectiveness and Toxicity of Yttrium-90 Microsphere Brachytherapy

Craig J. Baden, MD, MPH, John D. Roberson, BS, AB, Rojymon Jacob, MD, Omer L. Burnett III, MD; University of Alabama, Birmingham

Introduction: By exploiting the liver’s dual blood supply and the beta-emission of yttrium-90 (Y-90), microsphere brachytherapy enables treatment of primary or metastatic liver tumors with tumoricidal radiation doses while preferentially sparing normal liver parenchyma. Though utilization of Y-90 microsphere brachytherapy continues to increase, data regarding toxicity and effectiveness remain limited. Here, we report findings from a series of 82 Y-90 microsphere brachytherapy treatments.

Patients and Methods: Between October 2010 and August 2013, a total of 59 patients underwent 82 treatments with Y-90 SIR-Spheres at our tertiary care academic medical center. Median patient age was 60 years (range: 33–82 yr), and median Karnofsky performance score (KPS) was 80% (range: 40%–90%). Seventy-two treatments were completed in patients with Child-Pugh class A disease and 10 in class B. Of the 82 treatments, 36 (43.9%) were to colorectal carcinoma metastases, 15 (18.3%) to neuroendocrine tumors, 11 (13.4%) to cholangiocarcinoma, 5 (6.1%) to hepatocellular carcinoma, 5 (6.1%) to breast carcinoma, and 10 (12.2%) to other tumor types. The majority of radioembolization treatments were preceded by other therapies, including systemic therapy in 87.8%, liver resection in 18.3%, transcatheter arterial chemoembolization (TACE) in 14.6%, and radiofrequency ablation in 4.9%. The median maximum radiographic lesion size was 49 mm (range: 12–200 mm). Median treated tumor volume was 90.7 mL (range: 5–3,096 mL), constituting a median of 9.1% (range: 1.1%–78.5%) of the treated lobe. Median activity of microspheres was 1.03 GBq (range: 0–2.1 GBq). Procedures were uncomplicated in 73.2% of cases, while 15.9% developed stasis and 9.8% developed reflux. We collected laboratory, imaging, and other clinical data from the pretreatment visit as well as at the 1-, 3-, and 6-month and subsequent follow-up visits in order to determine toxicity, effectiveness, and survival associated with treatment.

Results: Acute toxicities of treatment were generally very mild and included fatigue (45.1%), anorexia (15.9%), weight loss (6.1%), abdominal discomfort (36.6%), nausea (24.4%), hepatic encephalopathy (12.2%), jaundice (3.7%), and ascites (3.7%). Grade 2 or higher laboratory toxicities included derangements of alkaline phosphatase (24.4%), albumin (23.2%), total bilirubin (19.5%), aspartate aminotransferase (AST) (12.2%), alanine aminotransferase (ALT) (3.7%), and international normalized ratio (INR) (3.7%).

Radiographic response was measured at 3 and 6 months post-treatment. Of 48 treatments with available imaging after 3 months, 25.0% showed partial response, 29.2% stable disease, and 45.8% progression. Median change in the maximum lesion diameter after 3 months was +1 mm (range: -22–92 mm). Six-month imaging was available for 28 treatments, with 28.6% demonstrating partial response, 42.9% stable, and 28.6% progression. Median change after 6 months was +1 mm (range: -47–70 mm). At 3 months, only 22.2% of neuroendocrine tumors had progressed, whereas 72.2% of colorectal carcinoma had progressed (P = .04). Radiographic response was not significantly associated with tumor diameter, tumor volume, previous chemotherapy, TACE, or liver resection.

Median survival from time of first treatment was 37.4 weeks (95% confidence interval [CI], 24.4–45.7). There were no significant differences in survival with respect to Child-Pugh class, tumor volume, tumor diameter, previous TACE, or previous systemic therapy.

Conclusion: Findings from this institutional series corroborate the safety of Y-90 microsphere radioembolization and demonstrate its effectiveness in treating a variety of unresectable primary and metastatic liver tumors.