Avoidance of axillary dissection in cN0 breast cancer patients with metastatic sentinel lymph node(s) using ACOSOG Z-0011 criteria: Is it appropriate for Indian patients?

Abstract

62 Background: A relatively newer algorithm for surgical management of axilla, where axillary node dissection (ALND) is avoided in cN0 EBC patients with 1 to 2 metastatic sentinel nodes (SLN) is now widely practiced in North America. ASCO & NCCN guidelines, and St Gallen consensus statement too have endorsed this strategy. This algorithm, based on the ACOSOG-Z0011 trial results has evoked quite a debate in India too. Concerns relating the quality of Z0011 data and its wide applicability persist. On the other hand, avoidance of ALND and its morbidity seems attractive to the oncologists and patients. In a single institution validation SLN Biopsy (SLNB) data-set, we evaluated the applicability of the “Z0011 strategy” to know its impact on an Indian patient cohort. Methods: In a prospective data-set of 120 cN0 EBC patients (mean age 51.1 years, T1 = 14, T2 = 106, mean tumor size 3.8 cm, 51.7% ER/PR+) who underwent validation SLNB (ALND irrespective of SLNB histology), such patients who fulfilled the selection criteria of ACOSOG-Z0011, i.e. those who underwent BCS and tangential field whole breast irradiation, and 1-2 metastatic SLNs were identified. Results: 66 (55%) of the 120 patients underwent BCS and tangential field whole breast irradiation. Of the 25 out of 66 patients with metastatic SLNs, 5 patients had 3 or more metastatic SLNs, and 2 had extra-nodal spread, thus not fitting the Z0011 criteria. Thus only 18 patients (15% of entire study cohort, and 27.3% of those undergoing BCS) with 1 to 2 metastatic SLNs were eligible for avoidance of ALND based Z0011 criteria. Of these 18 eligible patients, 7 (38.9%) had non-sentinel metastatic nodes. These 7, and the 3 with false negative SLNs could be seen as being left with undertreated axillae. Conclusions: In Indian context, where the majority of patients have large tumors and many opt for mastectomy, avoidance of ALND in presence of metastatic SLNs can be offered to a small proportion of patients. In a single institution validation SLNB data-set, only 15% patients qualified for avoidance of ALND using the Z0011 trial criteria. Besides, avoidance of ALND would have left 8.3% patients potentially undertreated in the axilla.