We studied the urinary excretion of hydroxyproline, measured as the hy
droxyproline-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 uri
nary excretion of hydroxyproline in patients with head and neck cancer
. The HOP/Cr was significantly higher in cancer patients than in the h
ealthy control. The ratio of patients with T3/T4 cancers was higher th
an in patients with benign tumors (p<0.05), chronic inflammatory disea
ses (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 tu
mor invasiveness which is masked in head and neck carcinomas such as s
kull base or maxillary carcinomas.