Is There a Subset of Patients with Early Stage Invasive Breast Cancer for Whom Irradiation May Not Be Indicated After Conservative Surgery Alone?

Irradiation is accepted as standard treatment following an excisional biopsy for stages I and II breast cancer and its equivalence to mastectomy has been demonstrated by a number of prospective randomized trials. However, the role of treatment directed to less than the entire breast for small invasive cancers has been questioned. This review has identified elderly women with primary tumors less than 2 cm and low histologic grade without an extensive intraductal component or lymphatic or vascular invasion, negative axillary nodes, and negative margins of resection as having a 15–20% risk of residual microscopic disease following an excision with a 2–3 cm margin of normal tissue. Breast recurrence rates in these patients range from 10–20% with conservative surgery alone and 5–10% with conservative surgery and irradiation This improvement in local control with irradiation has the potential for a 2–3% survival benefit. Therefore, even in this carefully selected group of patients irradiation decreases the risk of a breast recurrence. The role of wide excision and tamoxifen requires further investigation.