Evaluation of the clinical value of bone metabolic parameters for the screening of osseous metastases compared to bone scintigraphy

Bone turnover markers in serum and urine as diagnostic, prognostic and monitoring biomarkers of bone metastasis

Bone metastases are characterized by increased osteoblastic and/or osteolytic processes depending on the tumor type. The altogether destructive effect of metastasis formation promoted by increased metabolic activity raises the release of components from the osseous metabolism into the blood stream. These components are either enzymes directly involved in the alteration processes, metabolites/proteins that develop during this or bone matrix proteins released during this. These biomarkers are categorized in relation to their involvement in the bone formation or resorption as bone formation and resorption markers. Based on a PubMed literature search, a critical appraisal of the various biomarkers for diagnostic, prognostic, and monitoring purposes is given for patients with skeletal metastases caused by breast, prostate, lung, or renal cell carcinomas.

Procollagen assays in cancer

The synthesis rates of fibrillar collagens can be assessed in blood by measuring propeptides set free from corresponding procollagens before fiber formation. Type I collagen is the major component of the organic matrix of bone, but it is also found in other connective tissues. The serum concentration of the amino-terminal propeptide of type I procollagen, PINP, functions as a measure of type I collagen synthesis during normal bone turnover, but it is also released from bone metastases that involve an osteoblastic component. Type III collagen is a major constituent of soft tissues and the corresponding amino-terminal propeptide, PIIINP, reflects collagen synthesis. Circulating PIIINP tends to be affected by malignomas that grow in the peritoneal cavity or affect bone marrow. Many studies on procollagen markers in cancer have been cross-sectional or demonstrated treatment effects in patient groups. Markers that originate from bone turnover have wide reference intervals, but low biologic variability in individuals. Thus, they appear better suited for monitoring versus diagnostic purposes. There is still definite need for research on the use of procollagen markers in the followup of individual patients undergoing cancer treatment or being monitored after such treatment.

Is retention of zoledronic acid onto bone different in multiple myeloma and breast cancer patients with bone metastasis?

Zoledronic acid (Zol) is used to treat bone disease in both multiple myeloma (MM) and breast cancer patients with bone metastasis (BC). However, bones of MM and BC patients show a difference in retention of the bisphosphonate used for bone scintigraphy. Therefore, we hypothesized that disease-specific factors may differently influence Zol retention in MM and BC patients. We tested this hypothesis in an investigator initiated phase II clinical trial in which we compared the whole-body retention (WBrt) of Zol in a cohort of 30 multiple myeloma (MM) and 30 breast cancer (BC) (20 Zol naive and 40 with six or more previous administrations). On average, 62% of the administered Zol was retained in the skeleton of both MM and BC patients and independently of the number of treatments. WBrt of Zol did not correlate with cross-linked C-telopeptide (CTX) levels, but linear regression analyses showed that WBrt of Zol correlated with bone-specific alkaline phosphatase (bALP) levels in BC (p = 0.001), and with CTX/bALP in Zol naive MM patients (p = 0.012). Especially in BC patients, WBrt correlated with age (p = 0.014) independently of kidney function. In MM patients WBrt was found to primarily correlate with the extent of bone disease (p = 0.028). Multivariate linear regression analyses of the entire cohort pointed out that WBrt of Zol was best predicted by age (p < 0.000), osseous lesions (p < 0.001), and the preceding Zol dosing (p < 0.005) (r(2)  = 0.97). Comparing bone scintigrams with CT/X-ray images showed a poor correlation between sites of active bone disease and binding of scintigraphy bisphosphonate in 36% of MM patients and in 13% of BC patients. We conclude that WBrt of Zol is primarily determined by two non-disease related factors and only one disease related, but that there may be differences in retention or drug delivery at individual sites of bone disease between MM and BC patients. In order to find the optimal dosing of Zol, these observations should be taken into account.

Assessment of the Effects of Zoledronic Acid Therapy on Bone Metabolic Indicators in Hormone-Resistant Prostate Cancer Patients with Bone Metastatasis

Purpose. Assessment of effects of zoledronic acid therapy on bone metabolic indicators in hormone-resistant prostate cancer patients with bone metastasis. Material and Methods. Hormone-resistant prostate cancer patients who were identified to have metastases in their bone scintigraphy were taken to trial group. Before administration of zoledronic acid, routine tests for serum calcium, total alkalen phosphates were studied. Sample sera for bone metabolic indicators BALP, PINP, and ICTP were collected. Bone pain was assessed via visual analogue scale and performance via Karnofsky performance scale. Four mg zoledronic acid was administered intravenously once a month. Results. When serum levels of bone forming indicators PINP; BALP were compared before and after therapy, there were insignificant decreases (P = .33, P = .21, resp.). Serum levels of bone destruction indicator ICTP was compared, and there was a significant decrease after zoledronic acid therapy (P = .04). When performances of the patients were compared during therapy period, performances decreased significantly due to progress of illness (P = .01). All patients had ostalgia caused by bone metastases at various degrees. Significant decrease in pain scores was observed (P < .01). Conclusion. Zoledronic acid therapy decreased bone destruction and was effective in palliation of pain in patient with bone metastasis. Using bone metabolic indicators during followup of zoledronic acid therapy might be useful.