Continuing trends in the prevalence of right-sided lesions among colorectal carcinomas
B. Cady, M. D. Stone and J. Wayne
Division of Surgical Oncology, New England Deaconess Hospital, Boston, MA 02215.
The shift of colorectal carcinoma location toward the proximal colon has
been reported. This study documents that this statistically significant
trend has continued through 1992. An increase in transverse and descending
colon cancers is now apparent also. Only 59% of all large-bowel cancers
occurred distal to the descending colon between 1978 and 1992. Both
right-sided and distal large-bowel cancers have significantly decreased in
size, yet the incidence and frequency of lymph node metastases have not
changed over a 65-year interval (from 1928 to 1992). This constant
proportion of lymph node metastases may suggest distinct biological subsets
of cancers (lymph node avid vs lymph node avoidance). The progression from
small size with fewer metastases to large size with more lymph node
metastases occurs only in some of the smallest distal colorectal cancers.
