The metastatic spread of kidney and prostate cancers in man.

This research was performed on 66 autopsy reports of kidney cancers and 58 autopsy reports of prostate cancers. Two alternative hypotheses were tested, i.e. whether metastases spread at random from the primary tumor throughout the body or whether the metastatic spread occurs in steps, referred to as a cascade spread, requiring one or more disseminating sites. It was found that in cancer of the prostate two disseminating sites exist, i.e. bones and lungs. Metastases from the primary tumor appear first in the skeleton and then in the lungs, not vice versa. In cancer of the kidney, the lungs are the major disseminating site. The lymphatic areas did not seem to play a major role in the dissemination of both cancers; on the contrary, the presence of metastases in the lymph nodes seem to depend on the presence of carcinomatous cells in key sites, i.e. the skeleton and the lungs. These results, however, should be interpreted with caution, as explained in the text. Considerations were proposed for future research.