PET scans to diagnose Multiple Myeloma

FDG PET Reassures and Reveals High Risk Multiple Myeloma
11.5.02

Press Release from the Journal of Nuclear Medicine

Whole body FDG PET scans were able to identify previously undetected disease and also confirm that pre-cancerous conditions had not become active disease for 66 patients with multiple myeloma and related conditions studied by researchers from Cedars-Sinai Medical Center in Los Angeles California. Their findings were published in the November, 2002 issue of the Journal of Nuclear Medicine.

For sixteen patients with previously untreated active myeloma, the whole body scans identified those at high-risk, and provided important information on their disease’s status. One quarter of the patients had no evidence of disease on a routine skeletal bone scan, but showed up positive on the PET scan. Another patient’s disease was upgraded from Stage IA to Stage IIIA. For four of the 16 who were considered to have stage III disease, the PET scan revealed that the disease had spread outside the bone marrow, a finding which is linked to a poor prognosis for survival. Likewise for the 26 patients with relapsing disease, PET identified new diseases sites for 81% of those scanned, and for 23%, new non-marrow sites, with the same prognosis noted above.

The authors noted that PET may have particular value for both relapsed and active/untreated disease in patients with nonsecretory multiple myeloma. This version of the disease, which affects about 2% of those with multiple myeloma, can be particularly difficult to diagnose and stage early on because of the absence of the characteristic M-protein, and the fact that tumors are often less pronounced than the more common type. PET, which measures metabolic function, was able to identify disease [not visible through other means.]

According to the authors, for patients with conditions that may evolve into multiple myeloma, and who require frequent and detailed testing to monitor their condition, PET scans may be particularly useful and even potentially cost saving. The study included 14 cases of MGUS (monoclonal gammopathy of undetermined significance). This condition, in which there is excessive production of an antibody protein by abnormal plasma cells, evolves into multiple myeloma about 20% of the time. All had negative PET scans at their first evaluation. Only one of the patients scanned developed multiple myeloma, [All have had a second scan, and these confirmed the others had no active disease.]

The authors conclude that FDG PET can play an important complementary role, along with CT, MRI, and bone scans, in the diagnosis and staging of individuals with this disease, and that further studies will refine its best uses. MRI and CT, while able to identify lesions, have difficulty distinguishing between active disease and scare tissue, bone fractures or benign disease.

Whole-Body 18F-FDG PET Identifies High Risk Myeloma was written by Brian G.M. Durie, MD, Division of Hematology/Oncology, Department of Medicine, Cedars-Sinai Comprehensive Cancer Center and Alan D. Waxman, MD, Allesandro D’Agnolo, MD and Cindy M. Williams, BS, Division of Nuclear Medicine, Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California.

Source: http://myeloma.org/main.jsp?type=article&id=717