High urinary hydroxyproline excretion in patients with advanced head and neck cancer

We studied the urinary excretion of hydroxyproline, measured as the hydroxyproline-to-creatinine ratio (HOP/Cr), in sixty-six patients with head and neck disease including, 18 patients with head and neck cancer. Urinary hydroxyproline excretion was determined before treatment by the linear gradient elution method. Although the urinary excretion of hydroxyproline is considered to be useful in monitoring cancer tissue such as prostate carcinomas, no studies have been performed on the urinary excretion of hydroxyproline in patients with head and neck cancer. The HOP/Cr was significantly higher in cancer patients than in the healthy control. The ratio of patients with T3/T4 cancers was higher than in patients with benign tumors (p<0.05), chronic inflammatory diseases (p<0.01) or T1/T2 cancer (p<0.05). The high HOP/Cr with T3/T4 head and neck cancer corresponded to the extent of tumor invasion into the surrounding tissues such as muscles and bone. This suggests that HOP/Cr may be useful as a supplementary parameter for the assessment of tumor invasiveness which is masked in head and neck carcinomas such as skull base or maxillary carcinomas.