Have the American College of Surgeons Oncology Group Z0011 trial results influenced the number of lymph nodes removed during sentinel lymph node dissection?

Background The American College of Surgeons Oncology Group Z0011 trial results have the potential to bias the number of sentinel lymph nodes (SLNs) surgeons remove and axillary lymph node dissections (ALNDs) performed.

Methods A single-institution prospectively collected database was queried for T1 to T2 clinically node-negative breast cancer patients.

Results A total of 923 patients underwent breast conserving therapy with SLN biopsy. The mean number of SLNs retrieved before the trial's presentation (June 2010) was 2.7 compared with 2.6 after (P =.19). The mean number of SLNs retrieved before the trial's publication (February 2011) was 2.7 compared with 2.5 after (P =.10). Overall, the rate of completion ALND in patients with SLN macrometastases decreased from after presentation (84% to 63%; P <.01) and publication (83% to 62%; P <.01).

Conclusions There was no difference in the number of SLNs harvested after either the Z0011 trial presentation or publication; however, surgeons should be aware of the potential for bias. The trial appears to influence practice management with fewer completion ALNDs performed after its release.