Cytotoxic colloids such as radioactive gold and chromium phosphate have shown limited usefulness for clinical cancer therapy. In their favor is the fact that isotopes of suitable decay characteristics have been chosen to make their clinical use practical. Also, the transport characteristics of presently used colloids are relatively good. Thus, if radioactive gold or chromium phosphate is instilled into the peritoneal or pleural cavity, most of the colloid stays in the cavity where colloid is instilled.
The localization pattern of all colloids used to date, however, has seriously hampered their usefulness. Colloids, radioactive or not, share a common distribution in the body. They concentrate in normal tissue and in the normal portions of lymph nodes. Specifically, colloids are not taken up by tumor tissue or by that part of nodes replaced by tumor.1,2
For clinical usefulness in destroying cancer a localization pattern is needed which is the exact opposite