Urinary hydroxyproline in the management of breast cancer

Turnover of collagen in the body, 50% of which occurs in bone, results in the excretion of substantial amounts of hydroxyproline in the urine. Urinary hydroxyproline excretion and, in particular, the hydroxyproline/creatine ratio increase in the presence of primary and secondary neoplasms of bone. There is a good correlation between elevated urinary hydroxyproline excretion and metastases to bone from breast cancer. Moreover, in “early” breast cancer without demonstrable metastases we have found a good correlation between elevated levels of hydroxyproline in urine and axillary lymph node metastases at operation, subsequent development of bone metastases, and survival. In patients with disseminated disease undergoing hormone manipulation therapy, we have observed that urinary hydroxyproline excretion correlates with the response to treatment. Measurement of urinary hydroxyproline excretion appears to be a useful tool in staging breast cancer and monitoring the activity of the disease .