in situ”. In stage I, cancer has formed in the mucosa
of the colon wall and has spread to the sub-mucosa
layer of tissue under the mucosa. Cancer may have
spread to the muscle layer of the colon wall. Stage II
colon cancer is divided into stage IIA, stage IIB, and
stage IIC. During stage IIA cancer has spread
through the muscle layer of the colon wall to the
serosa outermost layer of the colon wall. In stage IIB
the cancer has spread through the serosa of the
colon wall but has not spread to nearby organs Stage
IIC: Cancer has spread through the serosa of the
colon wall to nearby organs. Stage III colorectal
cancer is divided into stage IIIA, stage IIIB, and
stage IIIC. In stage IIIA the cancer may have spread
through the mucosa of the colon and rectal wall to
the sub-mucosa and may have spread to the muscle
layer of the colon or rectal wall. The cancer has
spread to at least one but not more than three nearby
lymph nodes, or cancer cells have formed in tissues
near the lymph node or has spread through the
mucosa of the colon wall to the sub-mucosa. Cancer
has spread to at least four nearby lymph nodes. In
stage IIIB cancer has spread through the muscle
layer of the colon wall to the serosa. In stage IIIC
cancer has spread through the serosa of the colon or
rectal wall but has not spread to nearby organs.
During stage IV colorectal cancer is divided
into stage IVA and stage IVB. In stage IVA cancer
may have spread through the colon or rectal wall and
may have spread to nearby organs or lymph nodes.
In stage IVB the cancer may have spread through
the colon or rectal wall and may have spread to
nearby organs or lymph nodes. Also, cancer has
spread to more than one organ that is not near the
colon and rectum or into the lining of the abdominal
wall.