Breast cancer: metastatic patterns and their prognosis

From 1969 to 1977, metastatic disease developed in 145 of the 558 patients treated for breast cancer at the University of Maryland Medical System. The most common first site of distant spread was bone (51%), followed by lung (17%), brain (16%), and liver (6%). The remaining 10% of patients had multiple metastatic sites. Fewer than 10% of the entire group received adjuvant chemotherapy after primary treatment. When metastatic disease appeared, most patients had palliative systemic chemotherapy and/or irradiation. In general, patients with initially negative axillary nodes had a longer median time until relapse (development of metastatic disease) and a longer survival time after diagnosis of metastases than patients with initially positive nodes. Liver was the least common initial metastatic site; while liver metastasis was seen only in patients with positive axillary nodes, it carried the worst prognosis. The overall median survival time after metastasis was 12 months for bone and lung lesions, three months for brain lesions, and only one month for liver metastasis. The median survival of patients with multiple metastatic sites was 7.5 months. No correlation was found between time until relapse and survival after metastasis. Patients in whom distant metastases developed relatively soon after the initial diagnosis had the same postmetastatic prognosis as patients whose disease metastasized later. No correlation was found between age at initial diagnosis and metastasis-free interval or survival after metastasis.