RESUMEN
Type I collagen is the major constituent of bone and its breakdown products are increasingly used as sensitive markers of bone resorption. The N-terminal peptide-bound crosslinks of type I collagen (NTX) can be measured in urine and is useful for the monitoring of patients with metastatic bone disease. Studies have shown that raised NTX levels in metastatic bone disease correlate with an increased risk of complications and pathological fracture. The development of accurate and instantaneous point of care devices (POCD) would facilitate patient treatment and avoid delays in awaiting results from specialist laboratories. This study assesses the clinical performance of a single use POCD (OSTEOMARK NTx Point of Care Rx Home Use) to monitor NTX levels in patients with metastatic bone disease. NTX was measured in duplicate in 136 urine samples from patients attending clinic with metastatic bone disease using the POCDs. In our centre the frequency of bisphosphonate treatment is dependent on the NTX level, which is categorised into three groups (0-50, 50-100 and >100 nmol BCE/mmol creatinine). We used these categories to compare the clinical performance of the POCDs to that of a laboratory immunoassay. From a total of 272 devices, 231 (84.9%) successfully recorded a value in nM BCE/mM creatinine. Statistical analysis of the measure of agreement between POCD and laboratory assay found moderate agreement between the two assays (kappa 0.508). Out of the 72 samples with a laboratory assay value of <50, 53 (73.6%) were found to be within the same group recorded by POCD. From the 20 samples with a laboratory assay value of >100, 19 (95.0%) were found to be within the same category using POCDs. The measurement of urinary NTX by POCD appears to be a viable option for the monitoring of metastatic cancer patients. Whilst POCDs appear to record higher values than laboratory assays, the correlation between devices is good and with further research the NTX categories could be modified to accommodate this variation.
Asunto(s)
Biomarcadores de Tumor/orina , Neoplasias Óseas/secundario , Neoplasias Óseas/orina , Resorción Ósea/orina , Neoplasias de la Mama/orina , Colágeno Tipo I/orina , Péptidos/orina , Sistemas de Atención de Punto/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/métodosRESUMEN
PURPOSE: There are concerns over the late effects of cancer therapy, including accelerated bone loss leading to increased risk of osteoporosis. Treatment-related bone loss is well recognized in breast and prostate cancer, due to overt hypogonadism, but there has been little evaluation of the skeletal effects of chemotherapy alone in adults. This study assesses the extent of bone loss due to previous chemotherapy in men. EXPERIMENTAL DESIGN: The bone mineral density (BMD) of men who had received previously chemotherapy with curative intent for lymphoma or testicular cancers was compared with that of an age-matched population of men from a cancer control population that had not received chemotherapy. BMD was measured by dual-energy X-ray scanning. Additionally, measurement of sex hormones and the bone turnover markers N-telopeptide fragment of type I collagen and bone-specific alkaline phosphatase were done. All statistical tests were two sided. RESULTS: One hundred fifteen chemotherapy-treated patients and 102 cancer controls were recruited. There was no statistical difference in BMD between the chemotherapy and control groups at either spine or hip and the mean BMD values in both groups were no lower than that of a reference population. There were no significant differences in estradiol, luteinizing hormone, and testosterone, but follicle-stimulating hormone values were significantly higher in the chemotherapy group (P=0.011). The mean values of NH2-terminal telopeptide fragment of type I collagen and bone-specific alkaline phosphatase were within the reference ranges. CONCLUSIONS: The absence of accelerated bone loss following chemotherapy is reassuring and suggests that standard dose cytotoxic chemotherapy has no lasting clinically important direct effects on bone metabolism.