The Value of Serum Carboxyterminal Propeptide of Type 1 Procollagen in Predicting Bone Metastases in Prostate Cancer

Predictive value of collagen in cancer

Cancer is a complex disease and a significant cause of mortality worldwide. Over the course of nearly all cancer types, collagen within the tumor microenvironment influences emergence, progression, and metastasis. This review discusses collagen regulation within the tumor microenvironment, pathological involvement of collagen, and predictive values of collagen and related extracellular matrix components in main cancer types. A survey of predictive tests leveraging collagen assays using clinical cohorts is presented. A conclusion is that collagen has high predictive value in monitoring cancer processes and stratifying by outcomes. New approaches should be considered that continue to define molecular facets of collagen related to cancer.

Clinical usefulness of bone markers in prostate cancer with bone metastasis

Bone metastases occur in approximately 70% of patients with advanced prostate cancer. Skeletal-related events have been correlated with reduced survival and quality of life of patients with prostate cancer. Biochemical markers of bone metabolism (e.g. bone formation, bone resorption, osteoclastogenesis) might meet an unmet need for useful, non-invasive and sensitive surrogate information for following patients' skeletal health. Recently, zoledronic acid and denosumab have been proven to have the potential for preventing skeletal-related events among prostate cancer patients with bone metastasis. An improved understanding of the mechanisms underlying bone metastasis has also led to the recognition of multiple molecular targets and advances in therapy. However, estimating the efficacy of these agents is difficult. A clinical trial for castration-resistant prostate cancer is currently underway based on the definition of The Prostate Cancer Clinical Trials Working Group, and bone turnover markers are being used as conventional end-points for the clinical trial. Bone turnover markers are useful surrogate markers reflecting the effect of new therapeutic drugs and prognosis, as well as assessment of bone metastases. In particular, N-terminal cross-linked telopeptide of type 1 collagen and bone-specific alkaline phosphatase are widely used bone metabolism markers, and offer reliable surrogate markers to detect bone metastatic spread and to predict prognosis for prostate cancer patients with bone metastases.

Implications of serum bone turnover markers in prostate cancer patients with bone metastasis

OBJECTIVES

To assess the diagnostic accuracy of serum bone turnover markers for detection of bone metastasis in patients with prostate cancer (PCa) and to assess the usefulness of these markers as predictors of mortality from PCa.

METHODS

Serum total alkaline phosphatase, bone-specific alkaline phosphatase, carboxy-terminal pyridinoline cross-linked telopeptide parts of type-I collagen (1CTP), tartrate-resistant acid phosphatase type 5 b, and prostate-specific antigen (PSA) levels were measured in 222 patients (58 with bone metastasis, 57 with T2M0 PCa, 55 with T3M0 PCa, and 52 without PCa). Multivariate stepwise logistic regression analysis was used to identify independent predictors of bone metastasis. Correlation of serum marker levels with bone metastasis was assessed using receiver operating characteristics analysis. Multivariate Cox proportional hazards analysis was used to predict cause-specific survival in PCa patients with bone metastasis.

RESULTS

Serum total alkaline phosphatase, bone-specific alkaline phosphatase, 1CTP, tartrate-resistant acid phosphatase type 5 b, and PSA levels were significantly elevated in patients with bone metastasis, and correlated significantly with the extent of disease on bone scintigraphy. Multivariate stepwise logistic regression analysis demonstrated that serum PSA and 1CTP were significant predictors of bone metastasis. Receiver operating characteristics analyses showed that serum 1CTP level was the most reliable predictor of bone metastasis (area under the curve = 0.85). Multivariate Cox proportional hazards analysis revealed that only serum 1CTP was an independent prognostic factor for PCa-related death.

CONCLUSIONS

Serum 1CTP level was a more reliable marker than the others to detect bone metastatic spread and to predict survival probability in PCa patients with bone metastasis.

Prediction of bone metastases by combination of tartrate-resistant acid phosphatase, alkaline phosphatase and prostate specific antigen in patients with prostate cancer

OBJECTIVE

The clinical value of serum tartrate-resistant acid phosphatase (TRACP), prostate specific antigen (PSA), alkaline phosphatase (ALP), and prostatic acid phosphatase (PACP) for the prediction of bone metastases in prostate cancer were investigated.

METHODS

TRACP, PACP, ALP, and PSA serum levels were measured in 215 patients with prostate cancer, including 160 without and 55 with bone metastases. Correlation of serum marker levels with bone metastases was assessed using receiver operating characteristics (ROC) analysis. Sensitivity, specificity, accuracy, positive and negative predictive values were calculated for each serum marker. Multivariate stepwise logistic regression analysis was used to identify independent predictors for the presence of bone metastasis.

RESULTS

Mean serum TRACP, PACP, ALP, and PSA levels were significantly elevated in patients with bone metastases compared with those without (P < 0.05). PSA and PACP levels increased significantly with clinical stage of the disease, whereas TRACP and ALP levels only increased significantly in stage D2. Serum TRACP levels correlated significantly with extent of disease on bone scans. ROC analyses showed no significant differences in area under the curve for these markers. Logistic regression analysis demonstrated that PSA, ALP, and TRACP were significant predictors of bone metastasis. Predicted and observed risks of bone metastasis were well correlated when TRACP, ALP, and PSA were combined and bone scan could have been omitted in 70% of patients by assessing these three markers.

CONCLUSIONS

Serum TRACP can be considered a useful predictor of bone metastases in prostate cancer. A combination of TRACP, ALP, and PSA can obviate the need for a bone scan in 70% of cases.

Analysis of three-dimensional microarchitecture and degree of mineralization in bone metastases from prostate cancer using synchrotron microcomputed tomography

Bone architecture and mineralization are generally considered to be important components of bone quality, and determine bone strength in conjunction with bone mineral density. Although the features of bone quality have recently been studied under conditions in which bone density decreases, such as osteoporosis, little is known in osteosclerotic diseases. In this study, we compared the trabecular bone microarchitecture and degree of mineralization between osteoblastic bone metastasis and degenerative osteosclerosis using synchrotron radiation microcomputed tomography (SR-microCT). Small cubes of lumbar vertebrae were excised postmortem from the sites of osteoblastic metastasis, degenerative osteosclerosis, and comparative sites of normal subjects without skeletal lesions. The samples were imaged at high spatial resolution (voxel size = 6 microm) using the SR-microCT system developed at the synchrotron facility (SPring-8), Hyogo, Japan. The three-dimensional (3D) image data were then analyzed for the morphological parameters and the degree of mineralization of bone (DMB). Trabecular bone in metastatic lesions showed a highly connected and isotropic network pattern compared with the normal samples. Although the trabecular surface was markedly irregular in osteoblastic metastases, no significant difference was found in the mean trabecular thickness (Tb.Th) between osteoblastic metastases and normal tissue. The DMB of trabeculae in metastatic lesions had a broader range and lower mean than that of the normal tissue. In contrast, trabecular bone in degenerative osteosclerotic lesions showed a similar degree of anisotropy (DA) and connectivity to the normal tissue, whereas the trabecular thickness was greater in the degenerative osteosclerotic lesions. No significant difference in DBM between degenerative osteosclerosis and normal tissue was detected. These results characterize the difference in bone quality between osteoblastic bone metastasis and degenerative osteosclerosis. Further study on the relationship between bone quality and bone strength in these osteosclerotic lesions would improve our understanding of the pathogenesis of bone fragility.

Serum levels of bone turnover markers parallel the results of bone scintigraphy in monitoring bone activity of prostate cancer

OBJECTIVES

To investigate the usefulness of bone turnover markers as a modality for monitoring bone metastasis in patients with prostate cancer with bone metastasis.

METHODS

Serial measurements of pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), carboxyterminal pro-peptide of type I procollagen (PICP), prostate-specific antigen (PSA), and the percentage of the positive area on the bone scan were prospectively performed before and after hormonal therapy in 84 patients with prostate cancer with bone metastasis for median follow-up of 29 months.

RESULTS

Serial ICTP and PICP levels in 48 patients without progression of bone metastasis demonstrated a downward trend during treatment and were almost within the normal range by the end of follow-up. The remaining 36 patients, who had PSA failure with progression of bone metastasis, showed an upward trend for serial ICTP and PICP levels before the progression of bone metastasis. The rates of detecting bone progression using bone turnover markers were higher than those using PSA levels on the basis of the percentage of clinical effectiveness and receiver operating characteristic curves.

CONCLUSIONS

Serial measurement of bone turnover markers is useful for monitoring the bone activity of prostate cancer and might detect early progression of bone metastasis in patients with PSA failure.

Markers of bone turnover in prostate cancer

Prostate cancer is the most common malignancy in elderly men and is often associated with bone metastases. Although bone metastases are osteosclerotic, histological and biochemical studies clearly indicate an increase of both bone formation and bone resorption, providing the rational for using bisphosphonate as a palliative treatment in these patients. The recent development of specific and sensitive biochemical markers, reflecting the overall rate of bone formation and bone resorption, has improved the non-invasive assessment of bone turnover abnormalities in patients with prostate cancer. The immunoassays for bone-specific alkaline phosphatase and type I collagen propeptides are currently the most sensitive markers to assess bone, formation. The best indices of bone resorption are the immunoassay for the pyridinoline cross-links and the related peptides that can be measured in urine and more recently in serum. A better knowledge of the biochemistry, especially of the age-related post-translational modifications of type I collagen in the abnormal bone matrix, associated with bone metastases from prostate cancer may lead to markers of increased sensitivity. A recent example is the demonstration that the isomerization and racemization of the aspartic acid residue in C-telopeptides of type I collagen is impaired in patients with prostate cancer and bone metastases, a pattern than can be detected with specific conformational antibodies. The most sensitive markers of bone formation and bone resorption are markedly increased in patients with bone metastases compared with patients with cancer but without metastases, the levels correlating with the extent of the bone involvement. However, their sensitivity remains limited, suggesting that the currently available biochemical markers cannot be used as a surrogate for bone scintigraphy in the diagnosis of bone involvement. A few studies have suggested that the measurement of bone markers may be useful in the assessment of response to anti-endocrine therapy, although available data indicate a lower sensitivity than with prostates specific antigen. Additional longitudinal studies are required to assess the potential use of bone markers, especially to identify patients who relapse during the course of the treatment and, more specifically 3 those that result from the progression in bone metastases.Clearly, the established use of bone markers is for monitoring effects of bisphosphonate treatment. Several studies have shown a rapid decrease of bone resorption markers in patients with prostate cancer and bone metastases, the magnitude of the decrease correlating with the efficacy of the treatment in reducing bone pain. Thus, bone markers are likely to become a useful and objective tool to monitor bisphosphonate treatment and individual the therapy scheme.

Inability of bone turnover marker as a strong prognostic indicator in prostate cancer patients with bone metastasis: comparison with the extent of disease (EOD) grade

BACKGROUND

Although clinical investigations of bone turnover markers in prostate cancer patients have been conducted, the relationships of pretreatment levels of the markers to the prognosis of patients with bone metastasis has not been fully examined.

METHODS

The serum levels of carboxy-terminal propeptide of type I procollagen (PICP) and carboxy-terminal telopeptide of type I collagen (ICTP), alkaline phosphatase (ALP), and prostate-specific antigen (PSA) were examined in 48 untreated prostate cancer patients with bone metastasis, and the prognoses of the patients were evaluated using univariate and multivariate analyses.

RESULTS

The patients with low PICP or ALP values had significantly better outcomes in terms of cause-specific survival compared to the patients with high PICP or ALP values. There was no significant difference in survival between patients with high and low ICTP or PSA values. The multivariate analysis of PICP, ICTP, ALP, PSA, and extent of disease (EOD) grade revealed that only the EOD grade was an important prognostic indicator for survival.

CONCLUSIONS

These results demonstrate that the extent of bone metastasis evaluated by bone scintigrams is a more important prognostic indicator than are the serum biochemical markers of bone turnover.