Lay Summary: Theraspheres are being investigated for liver cancer and colon cancer metastases. It is considered investigational at this time.
TheraSphere — a therapy that consists of millions of microscopic, radioactive glass microspheres (20-30 microns diameter) — is infused into the arteries that feed inoperable liver tumors, bathing the malignancy in high levels of extremely localized radiation. In some studies of highly selected pateints the response rates and stabilization rates ranged between 20-40 percent. No survival benefit has been demonstrated and the technique is still in phase II studies. This therapy is currently considered to be investigational. A recent guideline states: “radio-labeled Yttrium glass beads, radio-labeled lipiodol or immunotherapy cannot be recommended as standard therapy for advanced HCC outside clinical trials”.
A recent study(Salem 2010) may be changing the standard of care. It enrolled 291 patients (77% male, 25% were more than 75 years old, and 73% had multifocal disease). This is the largest series ever presented of the treatment of primary unresectable liver cancer using radiation microspheres. Results showed that overall time to progression was 7.9 months (95% confidence interval [CI], 6.0 – 10.3). Using World Health Organization guidelines, the overall response rate was 42%. Using the European Association for the Study of the Liver guidelines, the overall response rate was 57%. Survival times differed significantly by cancer staging system (26.9 months for BCLC A vs 17.2 months for BCLC B) and by liver function score (17.2 months for Child-Pugh A vs 7.7 months for Child-Pugh B). The promise here is that the disease can be converted to something that can become surgically resectable or that the patients may be able to be liver transplanted.
Although the phase III trials of radioembolization are ongoing as a first-line treatment of patients with metastatic colorectal cancer, there are sufficient phase II and retrospective clinical data supporting its use in salvage therapy for most patients. Patients with hepatocellular cancer, neuroendocrine tumors, and other primary sites, including breast and lung, although they also have also shown promising response and survival increases in multi-institutional experiences.
L. A. Dawson Hepatic Arterial Yttrium 90 Microspheres: Another Treatment Option for Hepatocellular Carcinoma J. Vasc. Interv. Radiol., February 1, 2005; 16(2): 161 – 164.
Andrew Kennedy, Subir Nag, Riad Salem, Ravi Murthy, Alexander J. McEwan, Charles Nutting, Al Benson, Joseph Espat, Jose Ignacio Bilbao, Ricky A. Sharma Recommendations for Radioembolization of Hepatic Malignancies Using Yttrium-90 Microsphere Brachytherapy: A Consensus Panel Report from the Radioembolization Brachytherapy Oncology Consortium International Journal of Radiation Oncology*Biology*Physics, Volume 68, Issue 1, Pages 13-23
R. Salem, R. J. Lewandowski, B. Atassi, S. C. Gordon, V. L. Gates, O. Barakat, Z. Sergie, C.-Y. O. Wong, and K. G. Thurston Treatment of Unresectable Hepatocellular Carcinoma with Use of 90Y Microspheres (TheraSphere): Safety, Tumor Response, and Survival J. Vasc. Interv. Radiol., December 1, 2005; 16(12): 1627 – 1639
Andrew S Kennedy, Riad Salem Radioembolization (yttrium-90 microspheres) for primary and metastatic hepatic malignancies. Cancer journal Sudbury Mass (2010) Volume: 16, Issue: 2, Pages: 163-175
Bruix J, Sherman M, Practice Guidelines Committee, American Association for the Study of Liver Diseases. Management of hepatocellular carcinoma. Hepatology 2005 Nov;42(5):1208-36. [322 references]
R. Salem, Society of Interventional Radiology (SIR) 35th Annual Scientific Meeting: Abstract 34. Presented March 14, 2010.