EDITORIAL – BREAST ONCOLOGY
Optimizing Surgical Management of the Axilla After Neoadjuvant
Chemotherapy: An Evolving Story
Eleftherios P. Mamounas, MD, MPH, FACS
Orlando Health University of Florida Health Cancer Center, Orlando, FL
For patients with operable breast cancer and clinically
negative axilla who undergo surgery ﬁrst, sentinel lymph
node biopsy (SLNB) has been established as the gold
standard for pathologic evaluation of the axilla. When the
SLN is negative, no further surgery in the axilla is required.
Traditionally, intraoperative frozen section (FS) was used
to assess SLN status. However, randomized clinical trials
have shown that selected patients with clinically negative
axilla and limited SLN involvement can be spared from
completion axillary lymph node dissection (ALND).
Therefore, intraoperative FS currently is reserved primarily
for patients who do not meet criteria for inclusion or were
underrepresented in those trials (e.g., patients undergoing
mastectomy and those who have received neoadjuvant
chemotherapy [NAC] before the SLNB).
During the past several years, use of NAC has expanded
and currently is considered an alternative to adjuvant
chemotherapy for selected patients with operable disease.
Development of more active NAC regimens and
improvements in patient selection for NAC have resulted in
increasing rates of sterilization of subclinically or clinically
involved axillary nodes, providing an opportunity to further
de-escalate the surgical management of the axilla.
For patients who undergo upfront SLNB, the volume of
SLN involvement is an important predictor of the presence
of non-SLN metastases
but whether this is also the case
for patients who undergo SLNB after NAC is not known.
This question is clinically important as we continue to
work on further de-escalation of axillary surgery for
patients who have their involved axillary nodes
downstaged by NAC but are found to have small-volume
disease in the SLN, either on intraoperative frozen section
or on permanent pathologic evaluation.
In a recent issue of the Annals of Surgical Oncology,
Moo et al.
report on a large study from Memorial Sloan
Kettering Cancer Center that aimed to determine the sen-
sitivity of intraoperative SLN FS after NAC as well as the
association between volume of disease in the SLN (by FS
or permanent section) and probability of ﬁnding additional
non-SLN involvement at completion ALND. During a
9-year period (2008–2017), 702 patients (711 cancers) who
had SLNB after NAC were evaluated. All the patients had
clinical stage 2 or 3 disease, and about half of the patients
were clinically node-positive before NAC ([ 80% of
whom were histologically conﬁrmed). All the patients were
clinically node-negative by physical examination after
NAC and underwent SLNB. For the patients who were
clinically node-negative before NAC, SLN mapping was
performed with single or dual tracers, at the surgeon’s
discretion, but the use of dual tracers was mandatory for
the patients who were clinically node-positive before NAC.
Intraoperative FS examination was routinely performed,
showing that 181 patients had metastases, and 530 were
negative. Of the 530 node-negative cases, 33 were positive
on the ﬁnal pathology (false-negative rate of FS, 6.2%).
Among the patients with a positive FS, 2% had isolated
tumor cells (ITC) and no further disease at ALND, 23%
had micrometastases, and 69% had macrometastases (6%
did not undergo completion ALND). At ALND, 59% of the
patients with micrometastases and 63% of those with
macrometastases had at least one additional positive non-
SLN. Among the 33 patients with a false-negative FS, 30%
had ITC, 46% had micrometastases, and 24% had
macrometastases. Of these patients, 17 had ALND, and
59% had at least one additional positive non-SLN.
Ó Society of Surgical Oncology 2018
First Received: 21 April 2018
E. P. Mamounas, MD, MPH, FACS
Ann Surg Oncol