Confirmatory data
Other recent studies confirm the feasibility of this approach in women who have clinically negative nodes after NAC.
In 2013, the German study SENTINA (sentinel-lymph-node biopsy in patients with breast cancer before and after neoadjuvant chemotherapy) explored the false-negative rate in women who had sentinel node biopsy before or after neoadjuvant chemotherapy. Overall, it found an unacceptably high false-negative rate of 14% in women with node positive disease who converted to clinically negative nodal status. However, when the analysis was limited to those cases with at least two sentinel nodes, the false-negative rate was less than 10%, once more suggesting a potential role for sentinel node surgery after neoadjuvant chemotherapy.
In 2015, the Sentinel Node Biopsy Following Neoadjuvant Chemotherapy (SN FNAC) study highlighted the potential effect of sentinel node surgery after NAC. The prospective study showed not only that the strategy was safe, with a false-negative rate around 8%, but also that it could have eliminated complete axillary dissection in about 30% of the cohort.
The study enrolled 153 women with biopsy-proven node-positive breast cancer (T0-3, N1-2) who underwent both sentinel node surgery and complete nodal dissection. Immunohistochemistry of the retrieved sentinel nodes was mandatory, and the presence of any tumor cells in the sentinel node rendered it positive.
The sentinel node retrieval rate was 88%, and the false-negative rate, 8.4%. The study also employed dual tracers of isotope and blue dye in a majority of patients; this was associated with a threefold decrease in the false-negative rate in those patients, dropping it to around 5%. “By using sentinel node biopsy after NAC, axillary node dissection could potentially be avoided in at least 30% of patients who present with node-positive breast cancer,” the study’s team concluded.
Long-term consequences?
It’s increasingly clear that for carefully selected patients, with robust NAC response, a postchemotherapy assessment can accurately assess nodal disease – especially if dual tracers are employed, several sentinel nodes examined, and the biopsy-proven positive node is resected. What isn’t clear yet is the long-term effect of this strategy, Dr. Boughey said.
“Five years ago, when Z1071 was first being reported, I would discuss it in terms of the controversy, and give the pros and cons,” she said. “But now that we have more information about this strategy under our belts, I feel much more confident. However, we still do not have information on patients with node-positive disease who have been treated with sentinel node only after neoadjuvant chemotherapy and followed for 5 or 10 years. That’s the piece we just can’t have, without time.”
Dr. Boughey had no relevant financial disclosures.
SOURCE: Boughey JC. Session PS108.