Variations in Axillary Staging: Much Ado About Nothing?

Abstract

The debate regarding the role of lymphadenectomy in breast cancer persists despite the availability of 25-year follow-up data from the National Surgical Adjuvant Breast and Bowel Project (NSABP) B04 trial comparing radical mastectomy, total mastectomy with regional nodal irradiation, and total mastectomy with no nodal treatment, a study that was designed to address this question. This trial failed to show a survival benefit attributable to regional nodal surgery or radiation; however, critical review revealed that the trial was likely too underpowered to show this difference, and axillary lymph node dissection (ALND) remained an important component of surgical therapy to accurately stage the axilla, guide systemic therapy decisions, and minimize regional recurrence. Sentinel lymph node (SLN) biopsy, an accurate and less invasive alternative to axillary node dissection, has become the new standard of care for axillary staging, and adoption of this technique has allowed surgeons to avoid axillary dissection and many of its attendant morbidities in node-negative patients. Questions still remain, however, as to whether ALND is always necessary in patients with positive SLNs and considerable effort has gone into the development of nomograms and predictive models to identify a subset of patients with a sufficiently low probability of having additional non-SLN metastases for whom completion node dissection may be avoided. With the early closure of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial, it is unlikely that we will have ever have definitive evidence as to whether ALND improves survival in patients with positive lymph nodes; yet axillary lymph node staging remains an integral component of breast cancer treatment, and axillary lymph node status remains the most significant prognostic factor for disease recurrence and survival. All current guidelines for the management of invasive breast cancer include the performance of an axillary staging procedure to guide further treatment decisions, and the National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology state that SLN biopsy (SLNB) is the preferred method of axillary sampling when available. NCCN guidelines further state that the performance of ALND is considered optional in patients with ‘‘particularly favorable tumors, patients for whom the selection of adjuvant systemic therapy is likely to be unaffected, for the elderly, and for those with serious comorbid conditions.’’ These caveats allow physicians to balance the risks and the benefits of the procedure for an individual patient, i.e., the art of medicine, but should not result in lesser-quality care for any particular group of patients. In this issue, Halpern et al. have found that significant variation exists in the performance of axillary staging procedures with respect to age, race, and socioeconomic class. Although there is a growing body of literature citing disparities in breast cancer care across race and socioeconomic class, the most significant finding in this analysis of the National Cancer Database (NCDB) is the omission of lymph node biopsy (LNB) in the older population. Patients in the oldest quartile C 73) were more than three times as likely not to receive an axillary staging procedure compared to their younger counterparts (age 51 years). Such variation in axillary surgery in the elderly should not come as a surprise. In the era before SLNB (1985–1995), a NCDB report identified that women older than 70 were more than twice as likely not to receive ALND when undergoing breast-conserving surgery (BCS) for early-stage breast cancer, and after the introduction of SLNB (1998–2005), the authors of the current paper previously reported that among all patients undergoing axillary surgery for earlystage breast cancer, older patients were less likely to receive SLNB (odds ratio, 0.8; 95% confidence interval, 0.78– 0.82). Halpern et al. also cite other published reports of variations in the surgical management of breast cancer for Society of Surgical Oncology 2008