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Background Many cancers metastasize to bone, which may cause an increase in bone resorption because of the direct effects of the tumor itself or osteoclastic activation. Patients and Methods Levels of urinary cross-linked N-telopeptide of type I collagen (uNTx) and serum cross-linked N-telopeptide of type I collagen (sNTx) were measured in 100 patients with lung cancer and 50 patients with benign respiratory disease using the Osteomark NTx urine and serum assays (Osteomark, Princeton, NJ). Bone metastasis was diagnosed by bone scintigraphy. Receiver operating characteristic (ROC) analysis was used to evaluate the detection of bone metastasis. Sensitivity and specificity to detect bone metastasis were calculated when cutoff points were set to 64 nmol bone collagen equivalents (BCE)/mmol Cr for uNTx and 22 nmol BCE/L for sNTx. Results Patients with lung cancer and bone metastasis had significantly higher levels of both uNTx and sNTx (uNTx median [range], 61.3 [22.7-593.1] nmol BCE/mmol creatinine [Cr]; sNTx median [range], 19.7 [10.7-97.1] nmol BCE/L) than did patients with lung cancer without bone metastasis (uNTx median [range], 45.2 [19.8-153.0] nmol BCE/mmol Cr; sNTx median [range], 16.7 [11.0-28.4] nmol BCE/L), or patients with benign respiratory diseases (uNTx median [range], 40.6 [15.2-155.9] nmol BCE/mmol Cr; sNTx median [range], 14.8 [9.5-55.5] nmol BCE/L.). There was good correlation between uNTx and sNTx ( R = 0.807). Area under the curve (AUC) for ROC was 0.743 for uNTx and 0.712 for sNTx. The sensitivity and specificity for the diagnosis of bone metastasis were 48.0% and 86.0%, respectively, using uNTx, and 40.0% and 87.0%, respectively, using sNTx. Conclusion This prospective study indicates equivalency between sNTx and uNTx in sensitivity and specificity to detect bone metastasis, and both uNTx and sNTx may have value as aids in the diagnosis of bone metastasis in patients with lung cancer.

Background The bone resorption biomarker sNTx has been previously shown to add value as an aid in the diagnosis of bone metastasis in patients with lung cancer. The objective of this prospective study was to determine if periodic sNTx measurements could lead to early diagnosis of bone metastasis in patients with lung cancer. Methods Patients with newly diagnosed organ-confined lung cancer were enrolled. sNTx values were determined once each month using the OSTEOMARKTM serum NTx assay (Alere Medical). The presence or absence of bone metastasis was determined by monthly physical examination and by bone scintigraphy every 3 months for 12 months. All patients were required to provide written informed consent. Results Forty patients were enrolled between June and December 2010. One patient withdrew early and was excluded from analysis. The mean +/- 1 SD baseline level of sNTx was 17.5 +/- 4.4 nM BCE/L. Five patients developed bone metastasis (as characterized by bone scintigraphy) during the study period. The level of sNTx in subjects with bone metastasis was slightly increased (21.6 +/- 3.2 nM BCE/L), however, in these patients, there was no statistically significant difference between sNTx values at baseline (18.2 +/- 4.2 nM BCE/L) and when metastasis was diagnosed. (p = 0.176). When a cut-off value of sNTx was set to 22.0 nM BCE/L, the sensitivity and the specificity of detection of bone metastasis were 80.0% and 41.2%, respectively. Using this cut-off, the elevation of sNTx could predict bone metastasis at least one month before diagnosis by bone scintigraphy in all 5 patients, however, the specificity was relatively low for clinical implementation. Additionally, the sensitivity and the specificity of early detection of systematic spread of disease (including bone metastasis) were 70.6% and 45.5%, respectively. Conclusions Periodic determination of sNTx in patients with organ confined lung cancer did not provide sufficient specificity for it to be used for the early diagnosis of bone metastasis or disease progression. Disclosure All authors have declared no conflicts of interest.

e18036 Background: The bone resorption biomarkers urinary NTx (uNTx) and serum NTx (sNTx) have been shown to aid in the diagnosis of bone metastasis in patients with lung cancer. Patients with metastatic bone disease from lung cancer (MBDLC) are often treated with zoledronic acid. Zoledronic acid reduces the levels of bone resorption biomarkers and also the risk of skeletal adverse events in patients with MBDLC. We studied the effects of treatments including zoledronic acid on levels of sNTx during disease progression. Methods: Patients with MBDLC at the initial diagnosis were entered to this study. sNTx was measured once a month using the sNTx assay OSTEOMARK serum NTx (Alere Medical). MBDLC was characterized by monthly physical examination and by bone scintigraphy every 3 months for 12 months. All patients were required to provide written informed consent. Results: Twenty patients were enrolled between June and December 2010. The mean +/- 1 SD of the sNTx concentrations was 19.8 +/- 5.8 nM BCE/L at baseline. In the 16 patients receiving zoledronic acid, the levels of sNTx showed a significant decrease in the first month of treatment (baseline: 21.3 +/- 5.5 nM BCE/L; one month later: 13.6 +/- 2.7 nM BCE/L; p

e18044 Background: Many cancers metastasize to bone. Bone metastasis may cause an increase in bone resorption due to direct effects of the tumor itself or osteoclastic activation. This study evaluates the bone resorption biomarkers urinary NTx (uNTx) and serum NTx (sNTx) for the diagnosis of bone metastasis in patients with lung cancer. Methods: uNTx and sNTx were measured in 100 patients with lung cancer and 50 control patients with benign respiratory diseases using the uNTx:OSTEOMARKTM and sNTx:OSTEOMARKTM serum NTx assays (Inverness Medical Japan). Bone metastasis was characterized by scintigraphy. The extent of disease (EOD) was determined by the number of sites of bone metastasis. Area under the curve (AUC) for receiver operating characteristic (ROC) analysis was used to evaluate the detection of bone metastasis. Sensitivity and specificity of uNTx and sNTx to detect bone metastasis were calculated using cutpoints of 64 nM BCE/mM Cr for uNTx and 22 nM BCE/mM Cr for sNTx. All patients were required to...