Monitoring of multiple myeloma patients by simultaneously measuring marker substances of bone resorption and formation

Fifteen patients (13 males and two females; mean age, 63 years; age range, 46-84 years) with multiple myeloma were studied prospectively (range of follow-up period, 2-6 months) to elucidate the diagnostic validity of biochemical markers of bone formation (bone alkaline phosphatase and the C-terminal propeptide of type I procollagen) and bone resorption (urinary excretion of pyridinium cross-links) for monitoring these patients. Eleven of 15 patients received melphalan i.v. and prednisone p.o. every 4 weeks. All patients were given pamidronate i.v. for inhibition of bone resorption. The mean values of the urinary excretion of pyridinium cross-links were significantly higher in the patients fulfilling the criteria of 'progression' or 'relapse' than in those showing 'response' and those in the 'plateau phase' (P<0.05). In contrast, neither bone alkaline phosphatase nor C-terminal propeptide serum values differed significantly between these two groups (P > 0.05). The concentrations of both bone formation markers were significantly lower in the patients than in the samples obtained from apparently healthy persons (P < 0.001). There was a significant inverse correlation between the number of pamidronate courses and the serum concentrations of bone alkaline phosphatase (P<0.05). A lack of correlation was observed between the urinary excretion of pyridinium cross-links and all other laboratory parameters measured (serum concentrations of total protein, calcium, creatinine and (beta(2)-microglobulin). In conclusion, the urinary excretion of pyridinium cross-links might be a useful parameter for monitoring multiple myeloma patients. Decreased values of bone formation markers may be due to a suppressive effect of the bisphosphonate agents administered or reflect the severity of osteolytic lesions which have been described as being associated with unbalanced bone remodelling. (C) 1998 Elsevier Science B.V.