Donald R. Lannin, MD

About 10% to 15% of patients who undergo breast-conservation surgeryand radiation therapy will subsequently develop ipsilateral breasttumor recurrence (IBTR). This paper reviews the biology, clinical management,and outcome of this entity. Risk factors for IBTR includeyoung age, positive microscopic margins, gross multifocality, an extensiveintraductal component, and lymphatic vessel invasion. The standardtherapy following IBTR has been mastectomy, but interest in furtherbreast-conservation approaches has recently arisen. Although theoutcome following salvage therapy is quite good, the risk of distantmetastases for patients with IBTR is three to five times greater than forthose without recurrence. The reason for this association has been controversial,but it now appears that IBTR is both a marker of the underlyingbiologic aggressiveness of the tumor and a source for furthertumor metastasis. Monitoring of patients following lumpectomy andradiation therapy, and aggressive therapy for IBTR when diagnosed,are clearly warranted. Prognostic factors at the time of IBTR and implicationsfor local and systemic therapy are discussed.