The pattern of metastases in human breast cancer. Influence of systemic adjuvant therapy and impact on survival.

Of the 3,802 patients enrolled in the DBCG 77 protocols, 863 developed clinical recurrence within a median follow-up time of 4.9 years (range 2.0-7.0). More than 69% of these had their first recurrence confined to a single anatomical site and 12% had more than two metastatic sites. The most common sites were bone (35%), lung (23%), skin (22%), and regional lymph nodes (16%). The observation period after first recurrence was 3.6 years (range 0.8-6.4). Survival after recurrence was significantly related both to the location and the number of metastases. Patients who were given adjuvant chemotherapy (n = 134) had significantly fewer metastatic sites and significantly more frequent liver metastases than untreated patients (n = 50). Patients who received adjuvant tamoxifen (n = 154) had the same number of metastatic sites, but more often had lung metastases than untreated patients (n = 201). These results probably reflect that metastases in different anatomical locations differ with respect to sensitivity to antineoplastic treatments.