[Exploration on the modification of macroscopic classification of colorectal cancer]

To explore the feasibility and clinical significance of a modified macroscopic classification of colorectal cancer.

The data of 1379 patients with colorectal cancer surgically treated between 1975 and 2003 were retrospectively analyzed. The patients were divided into four groups according to the primary macroscopic appearance: protruding type (group 1), local ulcerative type (group 2), invasive type (group 3) and non-invasive ulcerative type (group 4). The new classification system was simplified into two types: non-invasive type (group A, including group 1 and 2) and invasive type (group B, including group 3 and 4). The histo-differentiation, invasive depth into the intestinal wall, distance and number of lymph node metastasis and 5-year survival rate were analyzed and compared among the groups.

There was no significant difference between group 1 and 2, and between group 3 and 4 in histodifferentiation, invasive depth into the intestinal wall, distance and number of lymph node metastasis and 5-year survival rate (P>0.05). However, after modification of the primary macroscopic classification, a significant difference was observed in all the above mentioned parameters between group A and group B (P<0.05).

Our results demonstrate that the clinicopathological characteristics of the group 1 and 2, and of the group 3 and 4 are similar to each other. So it is reasonable to merge the protruding type and local ulcerative type into non-invasive type, while invasive type and non-invasive ulcerative type into invasive type. This simplified macroscopic classification should be practical and instructive in diagnosis, treatment and prognosis of colorectal cancer.