Metastatic breast cancer: clinical course, prognosis and therapy related to the first site of metastasis.

Although metastasis is a frequent event in breast cancer patients, insight into the clinical course, prognosis and therapy with respect to the site of the first metastases has been poor and contradictory in former investigations. Follow-up data from 648 patients with metastatic breast cancer were statistically analyzed. Patients with bone metastases at first relapse had better overall survival (median 71 vs. 48 months; p < 0.001) and survival after first metastases (median 24 vs 12 months; p < 0.001) than patients with visceral metastases at first relapse. Bone was the site of first metastasis in 46%, and 71% of patients with metastatic breast cancer developed bone metastases. The localization of the second metastatic site was of prognostic relevance in patients with first visceral metastases, but not in patients with first bone metastases. The presence of osseous metastases correlated significantly with estrogen and progesterone receptor positivity, tumor grading I/II and S-phase fraction <5%. The better prognosis of patients with bone metastases is not determined exclusively by hormone receptor status. The disease is significantly more stable in patients with first bone metastases than in those with first visceral metastases.