FORT LAUDERDALE, FLA. — The use of
In Paget's disease of bone, biochemical markers are used to monitor treatment response. But, in patients with limited bone involvement, these global indices often remain in the normal range, said Dr. Devogelaer, professor of rheumatology at Catholic University of Louvain and Saint-Luc University Hospital, Brussels.
Positron emission tomography (PET) using
Twelve patients with monostotic Paget's disease underwent 1-hour dynamic
Changes in bone metabolism as measured by the PET scans were assessed in two ways: via dynamic plasma clearance of
The two values correlated with each other at all time points. Both showed huge activity prior to treatment and significant drops thereafter, by about 30% at 1 month, 40% at 6 months, and nearly 50% at 1 year.
In contrast, the biochemical markers correlated with the PET scan results at baseline but not after treatment: Total alkaline phosphatase dropped by about 25% at 1 year, but remained within the normal range throughout the study. Fasting levels of urinary N-terminal cross-linking telopeptide of type I collagen (NTX) decreased significantly up to 6 months, but not thereafter. Bone-specific alkaline phosphatase dropped by about 30%–35% at 1 month, but remained significant only up to 6 months. Such changes in biochemical markers are not adequate for follow-up, he noted.
In response to a comment that PET scans are expensive, Dr. Devogelaer said, “We hope that the cost will decrease. But, we see that with the biological parameters, there is no correlation after treatment. To appreciate the activity of monostotic Paget's disease of bone, we need something else.”
