How important is a completion node dissection for women with a positive sentinel node biopsy in breast cancer?
For women with a positive sentinel node biopsy in breast cancer, the current standard of care is to proceed with an axillary node dissection. However, there are risks associated with this procedure and one of the most problematic is the evolution of lymphedema--which can be a long lasting problem for women beyond their surgery. So, how important is a completion node dissection? This question has been addressed in a recent publication by Giuliano and colleagues reporting for the American College of Surgeons Oncology Group.
In the seminal Z11 study patients with T1-T2 breast cancers who had a positive sentinel node biopsy of up to two positive nodes were enrolled. The objective was to show that sentinel node biopsy (SNB) alone was not inferior to completion node dissection (AND) in this population. While 1900 patients were aimed for the study, it was closed early due to a lower than expected mortality rate and ultimately less than 900 were entered.
With a little over 6 years of follow-up, the median overall survival at 5 years was almost identical: 91.8% in those who underwent AND and 92.5% in those who were observed after SNB. More importantly perhaps (given the concern that sentinel node without completion axillary node dissection would increase the rate of relapse) is that disease free survival was also notably similar: 82.2% with AND and 93.9% with SNB. Importantly, however, is to realize that their treatment beyond surgical therapy was approached similarly: all patients went on to radiation therapy and nearly all patients were also treated with systemic chemotherapy. The authors further note that there were no differences in adjuvant treatment whether it be with chemotherapy (including the choice of agents), endocrine therapy, or both.
What these results point to is the importance of a multidisciplinary management strategy in breast cancer. It is very likely that important contributions to disease free and overall survivals are made beyond surgical treatment alone, particularly as we point to the contributions of radiation therapy in reducing local relapse rates (which in some studies has also been shown to correlate with distant relapse and even overall survival).
Given the importance of systemic and local therapy for breast cancer it makes surgical questions such as the Z11 study more relevant. It continues an evolution in the surgical management of breast cancer from radical to conservative in the hopes of preserving long term function and the body image of women diagnosed with breast cancer.