Prognostic significance of distant metastasis location in patients with metastatic colorectal cancers

Colorectal cancer is the fourth most frequently diagnosed cancer and the current TNM staging fails to take into account the different outcome among metastasis locations and the time of metastases. Here, we investigated the prognostic significance of different metastatic locations in patients with metastatic colorectal carcinoma (mCRC) in 496 patients diagnosed with synchronous mCRC and 559 patients diagnosed with metachronous mCRC between July 1984 and December 2003. The Cox proportional hazards regression showed that distant metastasis locations (liver and lung) were significantly associated with disease-specific survival in the univariate and multivariate analysis. Further survival analysis found that patients with metachronous liver and lung metastases had significantly shorter disease-specific survival than the other two patient groups with liver or lung metastases (P<0.001). However, there were no differences in disease-specific survival among three patient subgroups (liver metastases, lung metastases, and liver plus lung metastases) for patients with synchronous metastasis. Additional comparison analysis revealed that the disease-specific survival of patients with metachronous metastasis was significantly shorter than that of patients with synchronous metastasis. These results suggested that different distant metastases locations and different time of metastases have the different prognosis. Our study indicated that optimal TNM staging for mCRC should incorporate distant metastases locations and the time of metastases to provide a more effective and predictive model.