Treatment of the axilla in early breast cancer: past, present and future

Background: The optimal treatment of the axilla in early breast cancer is controversial. The present study reviews the pattern and predictors of regional recurrence (RR) and prognosis after RR in patients with early breast cancer treated by conservative surgery and radiotherapy (CS + RT). Implications of the results on current practice and future directions are explored. Methods: Between 1979 and 1994, 1158 patients with stage I or II breast cancer were treated with CS + RT at Westmead Hospital. Two groups of patients were compared: 782 patients who underwent axillary dissection (axillary surgery group) and 229 patients who received radiotherapy (axillary RT group) as the only axillary treatment. At least 10 lymph nodes were dissected in 82% of the axillary surgery group. Of the women in the RT group, 90% received RT to the axilla and supraclavicular fossa (SCF) only and 10% also received RT to the internal mammary chain (IMC). Results: With a median follow‐up period of 79 months for the axillary surgery group and 111 months for the axillary RT group, 27 patients developed a RR (2.8% and 2.2%, respectively). Seven patients (0.9%) in the axillary surgery group and three patients (1.3%) in the axillary RT group developed a RR in the axilla (P, not significant). Of the patients with SCF recurrences, 14 (1.8%) were in the axillary surgery group and one (0.4%) in the axillary RT group (P, not significant). One patient in the axillary surgery group developed concurrent axillary and SCF recurrences, while a patient in the axillary RT group developed an IMC recurrence. Twenty (74%) of the 27 patients with a RR developed a concurrent or subsequent distant relapse (30% and 44%, respectively). In the pathologically node‐positive patients, the axillary recurrence rate was higher in those who had less than five nodes removed (17%) than those who had 10 or more nodes removed (0%; P = 0.01). The SCF recurrence rate was higher in patients with four or more positive axillary nodes (9.5%) than in those with 0–3 positive nodes (1.5%; P = 0.003). Conclusion: Adequate treatment of the axilla by surgery or RT alone is associated with a low rate of RR. The incidence of distant relapse was substantial in patients who developed a RR, which gives emphasis to the importance of optimizing local–regional control.