INVESTIGATIONS ON BONE METABOLISM OF UROLOGICAL TUMORS FORMING METASTASES

Bone metastases of urological tumors occur in nearly 40% of all primar y tumors of the prostate, the kidney and the bladder. The quality of m etastases may be described as osteolytic, osteoplastic or mixed lesion . Whereas prostate cancers produce mainly osteoplastic lesions, renal cell carcinomas predominantly generate osteolytic lesions. In bladder cancer both forms of metastases occur in tantamount numbers. However, diagnostics still presents many difficulties, since it is not feasible to identify very small metastases until symptoms have manifested them selves. The purpose of our study was to evaluate measurement technique and classification of significant serum markers for monitoring the co urse of disease. Patients with primary urological tumors and metastase s in the skeleton were investigated and compared with healthy voluntee rs. Osteodensitometry was used to confirm and to replace radiological diagnosis of bone metastases. Thus it was possible to locate the exten t and obtain information on the maximum charge and the stability of me tastases. Our examinations revealed that distinct serum markers descri be the changes in bone evoked by metastases. In comparison with health y volunteers, patients with osteoplastic lesions and osteolytic lesion s showed increases in hydroxyproline and pyridinium crosslinks (signif icance at least p < 0.005). Osteocalcin was elevated only in osteoplas tic lesions versus healthy volunteers (p < 0.01). For diagnostics of o steoplastic and osteolytic metastases, either alkaline phosphatase or the skeleton-specific phosphatase (ostase) can be measured serological ly. Both parameters showed significant elevation in the patient groups when set against the healthy controls (both p < 0.0001). Compared wit h lytic lesions osteoplastic carcinomas revealed significant increase of alkaline phosphatase (p < 0.0001) and osteocalcin (p < 0.005). In e xamination of bone metabolism in patients with skeletal meastases the following parameters are of eminent interest: osteocalcin, hydroxyprol ine or pyridinium crosslinks, alkaline phosphatase or ostase. These se rological parameters could be helpful even with regard to early diagno sis of bone metastases. Evaluation of measuring techniques suggests qu antifying pyridinium crosslinks instead of hydroxyproline, because the y may be assessed without taking the patient's diet into account. Dete rmination of bone density may be helpful in diagnostics or control of therapy modalities.