Prevalence and Consequences of Axillary Lymph Node Dissection in the Era of Sentinel Lymph Node Biopsy for Breast Cancer.

Background: Despite clear guidelines for its use and wide adoption, no population-based study has examined the extent to which patients with early stage breast cancer are benefiting from sentinel lymph node biopsy (SLNB) by being spared a potentially avoidable axillary lymph node dissection (ALND) and its associated morbidity.

Objective: Examine variation in type of axillary surgery performed by surgeon volume; investigate the extent and consequences of potentially avoidable ALND.

Research Design/subjects: Observational study of older women with pathologically node-negative stage I-II invasive breast cancer who underwent surgery in a SEER state in 2008-2009.

Measures: Surgeon annual volume of breast cancer cases and type of axillary surgery were determined by Medicare claims. An estimated probability of excess lymphedema due to ALND was calculated.

Results: Among 7686 pathologically node-negative women, 49% underwent ALND (either initially or after SLNB) and 25% were operated on by low-volume surgeons. Even after adjusting for demographic and tumor characteristics, women treated by higher volume surgeons were less likely to undergo ALND [medium volume: odds ratio, 0.69 (95% confidence interval, 0.51-0.82); high volume: odds ratio, 0.59 (95% confidence interval, 0.45-0.76)]. Potentially avoidable ALND cases were estimated to represent 21% of all expected lymphedema cases.

Conclusions: In this pathologically node-negative population-based breast cancer cohort, only half underwent solely SLNB. Patients treated by low-volume surgeons were more likely to undergo ALND. Resources and guidelines on the appropriate training and competency of surgeons to assure the optimal performance of SLNB should be considered to decrease rates of potentially avoidable ALND and lymphedema.