N-telopeptide of type I collagen is useful for monitoring therapeutic response in non-small cell lung cancer patients with bone metastases

Abstract

Elevated levels of N-telopeptide of type I collagen (NTX) are associated with skeletal-related events and death. However, it is unclear whether NTX is useful for monitoring therapeutic response in non-small cell lung cancer (NSCLC) patients with bone metastases. Urinary NTX levels were assessed at baseline and after one cycle of chemotherapy in 30 NSCLC patients with bone metastases. NTX levels were categorized as normal (NTX <64nmol/mmol creatinine) or high (NTX ≥64nmol/mmol creatinine). In 30 patients, the median NTX level at 1month was significantly lower than that at baseline (P=0.0016). The NTX levels after treatment were significantly lower than those at baseline in 20 patients with partial response (n=2) or stable disease (n=18). However, no significant difference of the NTX levels was observed in 10 patients with progressive disease. Sixteen (53.3%) of 30 patients had high baseline NTX levels. Ten patients had normal NTX levels after one cycle of chemotherapy, whereas 6 patients also had high NTX levels after treatment. The 10 patients with normal NTX levels had significantly better prognosis than the 6 patients with high NTX levels. Urinary NTX levels at 1month after chemotherapy may be useful for predicting therapeutic response in NSCLC patients with bone metastases. Normalization of elevated baseline NTX at 1month after chemotherapy was associated with survival benefits.