Hematogenous metastatic patterns of curatively resected colon cancer were different from those of stage IV and autopsy cases.

The hematogenous metastases of colon cancer have primarily been explained by the cascade hypothesis based on the cadaveric study. However, we experienced several cases with isolated lung metastasis. The metastatic patterns of a total of 982 patients with colon cancer who underwent surgery were reviewed. The incidence of single-site metastasis in curatively resected cases was significantly higher than in Stage IV cases (P = 0.002). The frequency of liver metastasis was significantly lower in curatively resected cases than in Stage IV cases (P < 0.0001). The frequencies of liver metastasis in Stage IV cases and in autopsy cases reported previously were almost the same (84%, 85%). The frequency of metastasis after curatively resection that did not include the liver was 39%, and cases of isolated lung metastases accounted for 19%. The patterns of hematogenous metastases that are inconsistent with the cascade hypothesis are more common than previously thought in clinical cases, especially in curatively resected cases.