D. Luftner et al., The course of the urinary DPD-crosslink secretion in metastatic breast cancer - A possibility for response assessment, ANTICANC R, 19(4A), 1999, pp. 2537-2544
Background: Urinary deoxypyridinoline (DPD)-crosslinks have been shown to b
e a highly specific parameter for type I collagen metabolism. Materials and
methods: In a prospective breast cancer study, urine samples were collecte
d in after-care patients and in patients with bone metastases. DPD-crosslin
ks were measured every three weeks using a fully automated chemiluminescenc
e immunoassay. Bone metastases were confirmed by bone scan and/or x-ray, an
d were followed-up over six months. To validate the test, a receiver operat
ing characteristics (ROC)-curve was set up to find the DPD cut-off concentr
ation which separates patients with no evidence of disease (NED) from patie
nts with bone metastases. Results: 73 breast cancer patients (41 with NED,
32 with bone metastases) were included into the ROC analysis. At a DPD cut-
off value of 8 nmol/mmol creatinine, we found the best sensitivity (84.4%)
for the detection of bone metastases with a specificity of 70.7%. Patients
with stable bone disease under intravenous pamidronate treatment (90 mg q3w
) and specific therapy had a significant (p = 0.007) fall of the DPD-crossl
inks in comparison to the progressive subset with 72.7% falling below 8 nmo
l/mmol. Conclusions: We conclude that the net bone turnover is not increase
d at a DPD-crosslinks elimination < 8 nmol/mmol.