Objective : Although colorectal cancer invading the proper muscle (mp colorectal cancer) is an advanced form of cancer, it has a relatively good prognosis. However, there is a subgroup of patients with mp colorectal cancer who develop distant metastases and show a poor prognosis. We have examined the characteristics of such metastatic mp colorectal cancers from the perspective of stromal fibrosis.
Materials : Seventy-eight patients with mp colorectal cancer who underwent surgery in our hospital between 1996 and 2002.
Methods : Distribution of myofibroblast was determined as stromal fibrotic region by immunohistochemistry with α- smooth muscle actin (SMA), desmin and CD34. The area of stromal fibrosis was quantified using an image analyzer, and the fibrosis ratio to tumor area was calculated.
Results : Distant metastases from mp colorectal cancer were found in 8 patients (8/78, 10.2%. The fibrotic area of the distant metastasis group was 16.2±9.6
mm2, and that of the non-metastasis group was 14.0±9.0
mm2, showing no significant difference between groups. The fibrosis ratio of the distant metastasis group was 22.9 ± 8.0%, which was significantly higher than that of the non-metastasis group (17.3±7.5% ; p=0.043).
Conclusions : The fibrosis ratio of the distant metastasis group in mp colorectal cancer was higher than that of the non-metastasis group, suggesting that the fibrosis ratio of stromal fibrosis in colorectal cancer may be available as an index for poor prognosis in mp colorectal cancer.
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