大腸mp癌における間質の線維化と他臓器転移  [in Japanese] Relationship between stromal fibrosis and distant metastasis in patients with nip colorectal cancer  [in Japanese]

目的:大腸mp (muscularis propria)癌は進行癌であるものの比較的予後良好な大腸癌であるが,ときに他臓器への転移を認め,予後不良な一群が存在する.このような他臓器転移をする大腸mp癌がどのような性質を有しているかを間質の線維化の面から検討した.対象:1996年〜2002年に当科で経験した大腸mp癌手術症例78例を対象とした.方法:腫瘍最大割面像において免疫組織化学染色を施行し,α-smooth muscle actin (α-SMA)陽性,Desmin陰性,CD34陰性を筋線維芽細胞とし,その分布・増生を間質の線維化とした.画像解析装置を用い,間質の線維化面積を定量化し,断面積に対する線維化面積の比を間質の線維化率とした.結果:大腸mp癌他臓器転移症例は8例(8/78例,10.2%)にみられた.他臓器転移群の間質線維化面積は16.2±9.6mm^2,無転移群は14.0±9.0mm^2で差は認められなかった.また,他臓器転移群の間質線維化率は22.9±8.0%で,無転移群の17.3±7.5%と比べ有意に高値であった(p=0.043).結論:大腸mp癌の他臓器転移群は無転移群に比べて間質の線維化率が高値であった.大腸癌間質の線維化率は大腸mp癌予後不良因子となる可能性が示唆された.

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±9.6mm^2, and that of the nonmetastasis group was 14.0±9.0mm^2, 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.