B-362 A real-world study evaluating bone metabolism markers in advanced cancer patients with and without bone metastasis among Chinese population

Abstract Background Research indicates that bone metabolism markers such as urinary N-telopeptide (uNTx) provide good perspective in diagnosing bone metastasis and monitoring bone disease progress. However, there is limited data of bone metabolism markers among the Chinese population. This pilot study aims to evaluate urinary N-telopeptide/creatinine ratio (uNTx/Cr) and serum alkaline phosphatase (ALP), Calcium (Ca), Phosphorus (P) and Magnesium (Mg) levels in diagnosing bone metastasis and monitoring bone disease progress in advanced cancer patients with/without bone metastasis. Methods Advanced cancer patients with/without bone metastasis were recruited from The First Affiliated Hospital of Xinjiang Medical University from October 2023 to December 2024. The urine concentration of NTx and Cr and serum concentrations of ALP, Ca, P, Mg were measured using the automated QuidelOrtho Vitros 5600 system. Urinary marker levels were normalized relative to urinary creatinine levels. Patients with bone metastasis in this study were defined as newly diagnosed with bone metastasis, without history of taking bone-modifying agents. The levels of uNTx/Cr, ALP, Ca, P, Mg between the two groups were compared by the Mann-Whitney U test. A combined model was established to evaluate bone metastasis. Results Among 150 advanced cancer patients in our analysis, 51 were newly diagnosed with bone metastasis at a mean age of 61.08±11.25 years and 99 without bone metastasis at a mean age of 61.97±13.10 years, with no statistically significant difference (p=0.332). The median uNTx/Cr level was significantly higher in patients newly diagnosed with bone metastasis [87.62 (59.13, 129.90) nM BCE/nM Cr] than in advanced cancer patients without bone metastasis [47.10 (36.91, 70.76) nM BCE/nM Cr] (p<0.001). The median ALP level was also significantly higher in patients newly diagnosed with bone metastasis [102.19 (76.09, 143.35) U/L] than in advanced cancer patients without bone metastasis [82.61 (67.45, 99.97) U/L] (p=0.002). There was no significant difference in the levels of P and Mg between two groups (summarized in Table 1). The area under the receiver operating characteristic (ROC) curve was 0.788 for the combined model of uNTx/Cr, ALP and Ca for the diagnosis of advanced cancer with bone metastasis. This study has also observed a case of a 65-year-old non-small cell lung carcinoma (NSCLC) patient who was diagnosed with bone metastasis, with a uNTx/Cr level of 114.01 nM BCE/nM Cr before taking bone-modifying agents. Monthly testing after taking bone-modifying agents yielded uNTx/Cr levels ranging from 21.65 to 22.37 nM BCE/nM Cr. The declined result of uNTx/Cr levels was in accordance with the follow-up Emission Computed Tomography (ECT), indicating the improvement of bone metastases for disease progression. Conclusion The combined model of uNTx/Cr, serum ALP, and Ca can significantly improve the diagnostic efficiency of bone metastases from advanced cancer patients. Further studies are needed with larger sample sizes and more clinical data from the clinical practices such as follow-up skeletal-related events (SREs), number of bone lesions, etc. Since bone metabolism markers are more economical without radiation compared to imaging examination, more real-world data evidence bone markers can assist in diagnosing bone metastasis and monitoring bone disease progress.