Metastases in colo-rectal carcinoma by isotope bone scanning.

Eight of ten cases of colo-rectal cancer having positive radionuclide bone scans were observed in a Radiation Oncology Clinic in one year. Eight were referred to the institution after treatment elsewhere. In a series of fifty cases with their definitive therapy and evaluation at this institution, 33% of those with bone scans were positive. Review of recent literature shows that 50% of colo-rectal carcinoma have positive bone scans, usually following a multiple and widespread distribution including ribs, pelvis, vertebrae, skull or extremities. These studies indicate that bone scanning may greatly increase precision in staging of colo-rectal carcinoma and aid in the recognition of the truly localized primary lesion. The mechanism of spread of bone metastases in colo-rectal carcinoma was presumably through Batson's plexus.