Predictive value of the bone markers osteocalcin and C-terminal telopeptide for jaw osteonecrosis in high-risk prostate cancer patients on bisphosphonate therapy: A prospective study.

OBJECTIVE

To examine the predictive value of osteocalcin (OC) and C-terminal telopeptide (CTX) levels for jaw osteonecrosis in high-risk prostate cancer (PCa) patients taking bisphosphonates (BPs).

METHODS

Twenty-four patients were prospectively recruited in this study and followed from 2011 to 2015. All patients were diagnosed with metastatic PCa with secondary bone deposits and were on androgen deprivation therapy (ADT). All participants were started on 4mg of zoledronic acid intravenously every 4 weeks for two years. The patients were reviewed every three months with full blood count, blood biochemistry, PSA and measurement of OC and CTX. Patients also underwent dental/oral examination. OC and CTX levels in serum were calculated using the ELISA method.

RESULTS

A significant decrease in PSA levels was found (β=-0.06, SE=0.02, p=0.006). The levels of OC (β=-0.46, SE=0.14, p=0.001) and CTX (β=-0.01, SE=0.004, p=0.007) also decreased significantly during the two years of follow up. Osteonecrosis of the jaw was identified in three patients at two years. Patients with osteonecrosis also showed a decrease in OC and CTX levels. The mean OC reduction was 77.3% for patients with osteonecrosis and 12.6% for patients without osteonecrosis. The mean CTX reduction was 44.1% for patients with osteonecrosis and 9.62% for patients without osteonecrosis.

CONCLUSION

Our study demonstrated no clear association between the levels of serum OC and CTX and bisphosphonate-related osteonecrosis of the jaw (BRONJ). To date, there is no clinically useful biomarker for the prediction of jaw osteonecrosis. More studies are needed using different bone turnover markers in order to identify patients at risk for BRONJ.