Radioactive microsphere therapy is gaining in popularity among specialists who deal with both primary and metastatic solid tumors in the liver (see images on page 1 and "On the cover" box below). During the past 2 years, sessions dedicated to this therapeutic approach have been held in meetings of all major related specialties: interventional radiology, radiology, radiation oncology, surgical oncology, hepatobiliary surgery, nuclear medicine, and medical oncology.
More than 6,000 patients
With more than 6,000 patients treated in the United States alone in the past 3 years, a significant body of peer-reviewed literature has been published to aid in understanding how and in which patient population to use this treatment.
Key issues in 2007 have been refinement of patient selection and expansion of treatment to a variety of histologic tumor types. Major successes have been achieved in breast cancer metastases, cholangiocarcinoma, neuroendocrine metastases, and ocular melanoma. Several multi-institutional clinical trials and dedicated quality of life studies have either started or are expected to be completed soon in neuroendocrine, colorectal, and hepatocellular cancers.
None of this research or treatment application would be possible without a multidisciplinary approach that incorporates the latest in imaging technology to localize tumors, evaluate extent of disease, assess the safety of future microsphere treatment, and confirm treatment success (Figure 1). This pictorial shows how imaging is used in microsphere therapy.
Gauging response
PET imaging greatly assists in treatment planning and assessment of response in a large number of different tumor types affecting the liver in patients receiving radioembolization. Researchers at the Third Annual Symposium on Liver-Directed Microsphere Therapy presented compelling pretreatment and post-treatment PET scans of patients who received internal radiotherapy for unresectable and chemorefractory tumors from melanoma and from breast, colon, bile duct, pancreatic, esophageal, and neuroendocrine (see image) cancers. The general conclusion was that PET was more reliable than CT in gauging tumor response.
Carcinoid tumor
