Local-regional breast cancer recurrence following mastectomy. Local-regional recurrence patterns were investigated in 1392 patients with breast cancer. Primary treatment for all patients included a mastectomy. Nine hundred seventeen patients had negative nodes and did not receive systemic therapy. Four hundred seventy-five patients had node metastases and were randomized to receive different combinations of chemoendocrine therapy. Follow-up ranged between 5 and 16 years. Two hundred thirty (25.8%) node-negative patients have had recurrences, with the initial recurrence being local-regional in 9.2%. Two hundred forty-two (50.9%) node-positive patients have had recurrences, with the initial recurrence being local-regional in 17.1%. Larger tumors and more extensive node involvement were associated with more first local-regional recurrences. The relative percent of first local-regional recurrence among patients in whom cancer recurred was similar for node-negative and node-positive patients (35.4% and 33.5%, respectively). In 63.6% of patients in whom cancer recurred, first local-regional recurrence were distant. Larger tumors, more extensive node involvement, and a shorter disease-free interval after mastectomy were associated with more rapid appearance of distant recurrence among these patients. 