Background: 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.
Patients and methods: 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 <64 nmol/mmol creatinine) or high (NTX ≥64 nmol/mmol creatinine).
Results: In 30 patients, the median NTX level at 1 month 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.
Conclusion: Urinary NTX levels at 1 month after chemotherapy may be useful for predicting therapeutic response in NSCLC patients with bone metastases. Normalization of elevated baseline NTX at 1 month after chemotherapy was associated with survival benefits.