Irradiation of the tumor bed alone after lumpectomy in selected patients with early-stage breast cancer treated with breast conserving therapy

Backgrounds and Objectives We present the interim findings of our in‐house protocol treating the tumor bed alone after lumpectomy with low‐dose‐rate (LDR) interstitial brachytherapy in selected patients with early‐stage breast cancer treated with breast conserving therapy (BCT). Methods From 1 March 1993 through 1 January 1995, 50 women with early‐stage breast cancer were entered into a protocol of tumor bed irradiation alone using an interstitial LDR implant. Patients were eligible if their tumor was an infiltrating ductal carcinoma ⩽3 cm in diameter, surgical margins were clear by at least 2 mm, the tumor did not contain an extensive intraductal component, the axilla was surgically staged with ⩽3 nodes involved with cancer, and a postoperative mammogram was performed. Implants were positioned using a template guide delivering 50 Gy over 96 hr to the lumpectomy bed plus a 1–2‐cm margin. Local control, cosmetic outcome, and complications were assessed. Results Patients ranged in age from 40 to 84 years (median, 65). The median tumor size was 10 mm (range, 1–25). Seventeen of 50 patients (34%) had well‐differentiated tumors, 22 (44%) had moderately differentiated tumors, and in 11 (22%) the tumor was poorly differentiated. Forty‐five patients (90%) were node‐negative while five (10%) had 1–3 positive nodes. A total of 23 (46%) patients were placed on tamoxifen and 3 (6%) received adjuvant systemic chemotherapy. No patient was lost to follow‐up. The median follow‐up for surviving patients is 47 months (range, 37–59). No patient has experienced a local, regional, or distant failure. Three patients have died at 19, 33, and 39 months after treatment. All were without clinical evidence of recurrent disease and all deaths were unrelated to treatment. Good‐to‐excellent cosmetic results have been observed in 49 of 50 patients (98%) (median cosmetic follow‐up was 44 months with a range of 19–59). No patient has experienced significant sequelae related to their implant. Conclusions Interim results with treatment of the tumor bed alone with an LDR interstitial implant appear promising. Long‐term follow‐up of these patients and additional studies will be necessary to establish the equivalence of this treatment approach compared to standard BCT. J. Surg. Oncol. 1999;70:33–40. © 1999 Wiley‐Liss, Inc.