Breast Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Stage I, II, IIIA, and Operable IIIC Breast Cancer
A multicenter, randomized clinical trial sought to determine whether ALND is required after an SLN biopsy reveals an SLN metastasis of breast cancer. This phase III noninferiority trial planned to randomly assign 1,900 women with clinical T1–T2 invasive breast cancer without palpable adenopathy and with one to two SLNs containing metastases identified by frozen section to undergo ALND versus no further axillary treatment. All patients underwent lumpectomy, tangential whole-breast irradiation, and appropriate systemic therapy, and OS was the primary endpoint. Because of enrollment challenges, a total of 891 women out of a target enrollment of 1,900 women were randomly assigned to one of the two treatment arms. At a median follow-up of 6.3 years, 5-year OS was 91.8% (95% CI, 89.1%–94.5%) with ALND and 92.5% (95% CI, 90.0–95.1%) with SLN biopsy alone. The secondary endpoint of 5-year disease-free survival (DFS) was 82.2% (95% CI, 78.3%–86.3%) with ALND and 83.9% (95% CI, 80.2%–87.9%) with SLN biopsy alone.[Level of evidence: 1iiA] On the basis of the results of this trial, the medical necessity of ALND after a positive SLN biopsy in patients with limited SLN-positive breast cancer treated with breast conservation, radiation, and systemic therapy is called into question.
For patients who require an ALND, the standard evaluation usually involves only a level I and II dissection, thereby removing a satisfactory number of nodes for evaluation (i.e., 6–10 at least), while reducing morbidity from the procedure. Several groups have attempted to define a population of women in whom the probability of nodal metastasis is low enough to preclude axillary node biopsy. In these single-institution case series, the prevalence of positive nodes in patients with T1a tumors ranged from 9% to 16%.[52,53] In another series, the incidence of axillary node relapse in patients with T1a tumors treated without ALND was 2%.[Level of evidence: 3iiiA] Because the axillary node status remains the most important predictor of outcome in breast cancer patients, insufficient evidence is available to recommend that lymph node staging can be omitted in most patients with invasive breast cancer.