Purpose: The aim of this study is to evaluate stage IV breast cancer at the initial presentation by the review of a single institute' data. We also tried to figure out the factors to predict stage IV breast cancer. Methods: We reviewed the prospectively collected database of 1,424 consecutive patients with primary breast cancer at the National Cancer Center in Korea from October 2000 to January 2005. Results: The proportion of stage IV breast cancer was 2.7% (38/1,424). The median tumor size of the stage IV patients was 4.1 cm. The most common metastatic site was bone (47.4%) followed by lung (44.7%) and liver (36.8%). Metastases were found in 0.9% (6/672) of the T1 tumors, 2.4% (13/535) of the T2 tumors, 8.3% (4./48) of the T3 tumors, and 27.1% (13/48) of the T4 tumors (p<0.001). On multivariate analysis, the statistically significant predictors of distant metastasis were tumor size (>= 2 cm) (p=0.026), positive lymph node status (p<0.001), alkaline phosphatase (>104 IU/L) (p=0.013), aspartate transferase (>40 IU/L) (p=0.003) and CA15-3 (>32 U/mL) (p=0.025). Conclusion: Our study showed that the factors to predict distant metastasis of breast cancer were large size of tumor, positive lymph node status, elevated alkaline phosphatase, aspartate transferase and CA15-3. Therefore breast cancer patients with those clinical characteristics should be carefully evaluated to detect distant metastasis.
