Treatment outcome after tangential radiotherapy alone without axillary dissection in patients with early stage breast cancer with clinically negative axillary nodes

Purpose: Given the widespread use of adjuvant systemic therapy even in node-negative patients, the routine use of axillary dissection has been questioned. Our goal is to determine the risk of nodal failure in patients with early stage invasive breast cancer with clinically negative axillary lymph nodes who were treated with 2-field tangential breast irradiation alone, without axillary lymph node dissection or a third nodal field. Materials and Methods: 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 received tangential breast irradiation without axillary dissection. After gross total excision of the primary tumor, whole breast radiotherapy was given to a dose of about 45 Gy, followed by a boost. The median total dose to the tumor bed was 61 Gy. Median age was 69 years (range: 49 - 87); 57 patients (62%) were ≥ 66 years of age at diagnosis. Clinical characteristics known to affect the risk of axillary involvement are given in the table. Nine patients had microinvasive disease. Fifty-three patients received adjuvant tamoxifen, 1 received adjuvant chemotherapy, and 2 patients received both adjuvant tamoxifen and chemotherapy. Median follow-up time for the 79 survivors was 50 mos (range: 15 - 96). Three patients (3%) have been lost to follow-up after 20 - 32 mos. Results: No isolated regional nodal failures were identified. One patient (T1c, non-palpable, not on tamoxifen) developed a local failure at 31 mos; on salvage MRM she had (1(12)) positive axillary lymph nodes. This patient is currently on tamoxifen and NED 6 mos later. One patient (T1b, presentation unknown, on tamoxifen) developed a recurrence in the breast only at 64 mos, successfully salvaged with wide excision alone; she is NED 16 mos later. One patient (T1b, palpable, on tamoxifen) developed simultaneous local (cutaneous) and distant failures at 31 mos. Six patients developed distant failures only. One patient developed a contralateral DCIS at 10 mos managed twice with excision alone. Two patients developed other cancers (1 lung, 1 endometrial). Conclusions: 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