Comparative study of prostate specific antigen (PSA), C-terminal propeptide of blood type I procollagen (PICP) and urine type I collagen-crosslinked N telopeptide (NTx) levels using bone scintigraphy in prostate cancer patients

We compared the ability to diagnose skeletal metastasis between serum prostate specific antigen (PSA), C-terminal propeptide of blood type I procollagen (PICP), and urine type I collagen-crosslinked N telopeptide (NTx) in prostate cancer patients. In sixty-nine patients with prostate cancer, bone scintigraphy was performed, and serum PSA and PICP and urine NTx were measured. The median level of serum PSA in the osseous metastasis-negative group (n = 33) was 0.80 ng/ml being significantly lower as compared to the osseous metastasis-positive group (n = 36, 7.70 ng/ml) (p < 0.0001). The serum PICP and urine NTx/Cr levels appeared lower in the osseous metastasis-negative group than the osseous metastasis-positive group, but there was no significant difference. Logistic regression analysis showed that ability to diagnose skeletal metastasis of serum PSA was 68.1% and superior to those of serum PICP (56.5%) and urine NTx/Cr (53.6%). Serum PSA improved the ability to diagnose skeletal metastasis when combined with serum PICP or urine NTx/Cr. When patients were grouped according to the extent of disease grade (EOD grade) nomenclature, Spearman's correlation coefficient by rank showed that serum PSA was most significantly correlated with EOD grade (p < 0.0001). In 14 patients whose skeletal metastases progressed or regressed, the change of serum PSA more clearly separated the osseous metastasis-regression group and osseous metastasis-progression group than did serum PICP and urine NTx/Cr. Serum PSA was more reliable than bone resorption and formation markers produced by crosslinking of type I collagen.