Urinary hydroxyproline excretion in patients with cancer

Twenty-four hour urinary hydroxyproline, creatinine and calcium excretion determinations, and bone roentgenograms were obtained sequentially at 3-month intervals, or less, in 100 patients with various advanced malignancies. Radiologically demonstrated bone metastases correlated better with the urinary hydroxyproline/creatinine ratio (HOP/Cr) than with the absolute 24-hour urinary hydroxyproline excretion. Abnormal HOP/Cr excretion preceded the development of clinical and roentgen evidence of metastases in bone, in both breast and lung cancer patients, by 1 to 7 months. Patients with a normal HOP/Cr excretion did not develop radiologic evidence of bone metastases over a period of 6 to 19 months. An examination of the urinary HOP/Cr excretion ratio may well be of value in detecting early bone metastases and be useful for appropriate staging of patients with carcinoma.