4: Axillary Staging Is Not Justified in Postmenopausal Clinically Node Negative Women Based on Nodal Disease Burden

The RxPONDER trial showed no benefit of adjuvant chemotherapy in postmenopausal women with estrogen receptor-positive (ER+), HER2- breast cancer and limited nodal burden (pN1) with a recurrence score ≤ 25 suggesting that axillary staging could be omitted in clinically node negative (cN0) patients if significant numbers of women do not have pN2-3 disease. We sought to evaluate the rate of pN2-3 disease in a large cohort of postmenopausal women presenting with cN0 breast cancer.


Methods:

Consecutive postmenopausal cT1-2N0 patients who underwent axillary surgery from 2/2001 – 12/2011 were identified from a prospectively maintained database. Clinical and pathologic characteristics associated with pN2-3 disease were examined using Chi square or Fisher’s exact tests.


Results:

Of 3,363 postmenopausal women with cT1-2N0 breast cancer, the median age was 58 years (IQR 48-67), and median tumor size was 1.3 cm (IQR 0.90-1.90 cm). After axillary staging, 2600 (77.3%) patients were pN0, 643 (19.1%) were pN1, and 120 (3.6%) had pN2-3 disease. The rate of pN2-3 disease did not differ across subtypes (4.4% HER2+, 3.5% triple-negative, 3.5% ER+/HER2-, p=0.70). Clinical and pathologic characteristics for the subset of ER+/HER2- patients, stratified by nodal status, are shown in Table 1. On multivariable analysis, age < 65 years (OR 2.38, 95% CI 1.32-4.49), lymphovascular invasion (OR 5.29, 95% CI 2.72-11.2), multifocal/centric tumors (OR 3.08, 95% CI 1.79-5.32), and tumor size > 2 cm (OR 5.51, 95% CI 3.05-10.4) were significantly associated with pN2-3 nodal burden. Of 506 patients with tumors > 2 cm, 49 (9.7%) had pN2-3 disease; in the subset of 90 patients who were younger than 65 years and had multifocal/centric tumors > 2 cm, 23 (25.6%) had pN2-3 disease.


Conclusions:

In postmenopausal women with cN0 disease, pN2-3 nodal burden is uncommon and omitting axillary staging would not miss a significant number of patients who might benefit from adjuvant chemotherapy. Information available preoperatively indicating a higher risk of nodal disease, such as younger age and large, multifocal tumors, should be considered in the multidisciplinary management of the axilla.