Serial spot hydroxyproline/creatinine ratios in metastatic prostatic cancer.

Analysis of urinary hydroxyproline levels offers a marker to monitor osseous involvement in patients with metastatic malignancies. Such a marker is needed in patients with prostatic cancer when bone metastases predominate. Thirty-two men with stage D2 prostatic cancer were monitored by bone scan, acid and alkaline phosphatase values, and urinary hydroxyproline, beginning from 4 to 36 months after initiation of hormonal manipulation and/or systemic chemotherapy. In patients with disease progression determined by bone scan serial urinary hydroxyproline values progressively increased and were significantly elevated compared to urinary values obtained from patients with a stable or improving scan (p less than 0.001). Simultaneous alkaline phosphatase determinations showed less significant differences between patient groups. Acid phosphatase did not reliably indicate osseous response to therapy. These data suggest that urinary hydroxyproline values are predictive as an early objective sign of osseous response in patients receiving therapy for stage D2 prostatic cancer.