Treatment outcome after tangential radiation therapy without axillary dissection in patients with early-stage breast cancer and clinically negative axillary nodes.

PURPOSE: To determine the risk of nodal failure in patients with early-stage invasive breast cancer with clinically negative axillary lymph nodes treated with two-field tangential breast irradiation alone, without axillary lymph node dissection or use of a third nodal field. METHODS AND MATERIALS: Between 1988 and 1993, 986 evaluable women with clinical Stage I or II invasive breast cancer were treated with breast-conserving surgery and radiation therapy. Of these, 92 patients with clinically negative nodes received tangential breast irradiation (median dose, 45 Gy) followed by a boost, without axillary dissection. The median age was 69 years (range, 49-87). Eighty-three percent had T1 tumors. Fifty-three patients received tamoxifen, 1 received chemotherapy, and 2 patients received both. Median follow-up time for the 79 survivors was 50 months (range, 15-96). Three patients (3%) have been lost to follow-up after 20-32 months.
RESULTS: No isolated regional nodal failures were identified. Two patients developed recurrence in the breast only (one of whom had a single positive axillary node found pathologically after mastectomy). One patient developed simultaneous local and distant failures, and six patients developed distant failures only. One patient developed a contralateral ductal carcinoma in situ, and two patients developed other cancers.
CONCLUSION: Among a group of 92 patients with early-stage breast cancer (typically T1 and also typically elderly) treated with tangential breast irradiation alone without axillary dissection, with or without systemic therapy, there were no isolated axillary or supraclavicular regional failures. These results suggest that it is feasible to treat selected clinically node-negative patients with tangential fields alone. Prospective studies of this approach are warranted.