Baseline levels of ICTP and NTX higher in patients with bone metastases.
CHICAGO—Bone remodeling markers may be useful for diagnosing and following prostate and breast cancer patients with bone metastases, according to researchers.
Bone metastases frequently are the first manifestation of disseminated tumor infiltration in
patients with prostate cancer, they explained. For this reason, the bone resorption marker peptide-bound collage type 1 cross-links C-telopeptides (ICTP) and bone formation marker N-terminal pro-peptide of type 1 collagen (NTX) might be of diagnostic relevance.
Studies have shown that the serum levels of these two substances correlate with the presence of bone metastases. Until now, little has been known about the influence of endocrine and bisphosphonate therapies.
Frederik Wenz, MD, professor of radiation oncology at the University of Heidelberg and the chairman of radiation oncology at the University Medical Center Mannheim, Mannheim, Germany, and his colleagues prospectively studied 172 patients without bone metastases (77 with prostate cancer and 95 with breast cancer), and 36 patients with bone metastases (18 prostate cancer patients and 18 breast cancer patients). The mean age of the patients was 63.4 years.
For this longitudinal follow-up study, ICTP and NTX were mea-sured in serum samples. All patients were treated according to clinical guidelines with endocrine therapy, bisphosphonates and/or radiotherapy if required, according to the investigators.
Baseline serum bone marker levels were higher in patients with bone metastases compared with those without, the researchers reported. The ICTP was 5.44 µg/L for patients with bone metastases versus 4.72 µg/L in patients without bone metastases. The NTX was 48.3 µg/L for the patients with bone metastases versus 41.9 µg/L for those without.
In addition, Dr. Wenz and his collaborators found that bisphosphonate therapy reduced ICTP values on average by about 0.6 to 0.7 and NTX values by 10 to 20 µg/L. Tamoxifen therapy reduced ICTP and NTX values, whereas aromatase inhibitors led to a reduction of ICTP and an increase in NTX. Se-rum levels of NTX were significantly higher in patients on aromatase inhibitors compared with patients on tamoxifen.
The investigators reported their findings here at the American Society of Clinical Oncology annual meeting.
“We have seen that the serological bone markers are different in men than in women,” Dr. Wenz told Renal & Urology News.
“One of the interesting findings was that, especially in patients with prostate cancer undergoing LHRH [luteinizing hormone-releasing hormone] therapy in combination with anti-androgens, the bone remodeling markers are really dramatically increased and it makes us think that it may be useful to consider prophylactic bisphosphonate therapy in these patients.”