TYPE-I COLLAGEN DEGRADATION PRODUCT (ICTP) GIVES INFORMATION ABOUT THE NATURE OF BONE METASTASES AND HAS PROGNOSTIC VALUE IN PROSTATE-CANCER

Although osteosclerotic bone metastases are characteristic of prostate cancer, mixed metastases with a lyric component are not uncommon. Typ e I collagen is synthesised by osteoblasts and accounts for about 90% of the organic matrix of bone. We have used new specific immunoassays for PICP (carboxyterminal propeptide of type I procollagen) and ICTP ( cross-linked carboxy-terminal telopeptide of type I collagen) which al low simultaneous assessment of the synthesis and degradation of type I collagen respectively. Forty patients with bone metastases due to pro state cancer at the time of diagnosis were investigated with these met hods. Twenty-three of them had sclerotic (S) and 17 had mixed metastas es with sclerotic and lyric components (S + L) as assessed by radiogra phs. The concentrations of PICP and ICTP in serum as well as the activ ity of alkaline phosphatase (AP) were increased in all patients of the S + L group, who had more aggressive bone disease and a shorter survi val than the S group (P<0.017). The ICTP level was above the reference range in half of the patients in the S group, whereas the PICP and AP levels were elevated in 35%. Of the bone markers, only ICTP was of pr ognostic significance (P<0.05). We conclude that ICTP and PICP give in formation about the type and activity of the skeletal metastases. In a ddition, ICTP predicts prognosis.