Collagen telopeptide (serum CTX) and its relationship with the size and number of lesions in osteonecrosis of the jaws in cancer patients on intravenous bisphosphonates

Abstract

Bisphosphonate has clearly become one of the major risk factors of ONJ. Concerns about ONJ are also seen in Asian countries including Korea. The use of serum CTX is not yet evidence based but the marker will be usable as a reference laboratory test in evaluating the risk of ONJ in the near future. Bagan et al. did a very interesting study with their valuable data. In their article, they correlated the raw value of serum CTX and the number and size of ONJ lesions of the investigated patients and there was no significant correlation. Basically, these two parameters were separately considered. It would have been interesting if these two parameters (size and number) had been considered simultaneously. The staging of the individual ONJ lesions should be considered when we evaluate ONJ lesions. Regarding the serum CTX values, the authors seemed to use raw value of serum CTX to conduct this study. Compared with uninary CTX and NTX, serum CTX is a relatively stable marker of telopeptide but it has also day-to-day variability, so it may be more logical to categorise the values into range values that were proposed by Marx. In this way, their correlation might have been significant. Based upon our data of oral bisphosphonate related osteonecrosis patients, which are submitted to be published, we found significant correlation between risk assessment according to serum CTX and the severity of ONJs which considered the number and staging of the ONJs. By means of such simultaneous consideration of the number and the staging of ONJ lesions of each patient, it might be possible for us to set up a system for a stratified evaluation of our patients.