The value of intraoperative frozen section examination of sentinel
lymph nodes in breast cancer
S. van de Vrandea, J. Meijerb, A. Rijndersc, J.H.G. Klinkenbijla,*
aDepartment of Surgery, Rijnstate Hospital, PO Box 9555, 6800 TA Arnhem, The Netherlands
bDepartment of Pathology, Rijnstate Hospital, Arnhem, The Netherlands
cDepartment of Nuclear Medicine, Rijnstate Hospital, Arnhem, The Netherlands
Accepted 28 July 2008
Available online 10 September 2008
Background: Sentinel node biopsy is a standard diagnostic component for the treatment of patients with a primary mammary carcinoma. By
concomitantly performing intraoperative lymph node biopsy and primary tumor resection, patients with a positive sentinel node (SN) are
not subjected to the inconvenience and risks of second surgical intervention. The aim of this retrospective study was to determine the sen-
sitivity, accuracy and long-term consequences of the frozen section (FS) examination of the SN in breast cancer patients.
Methods: Sentinel lymph node biopsy was performed in 615 patients with an invasive tumor of the breast. Frozen sections of the SN were
taken from the optimal cross-sectional surface. Serial sections were made from the remaining SN and stained using hematoxylineeosin and
Results: Sentinel node frozen biopsy accurately predicted the state of the axilla in 559 (90.7%) patients. There were 50 false-negative find-
ings in patients with sentinel node metastases. The sensitivity and specificity of the intraoperative frozen section examination were 71.6%
and 100%, respectively. Follow-up (mean 36.3 months) of all false-negative cases showed no development of local axillary recurrence. The
results demonstrated no significant relation between tumor size and frozen section sensitivity. Frozen section investigation was less sensitive
in ascertaining micrometastases (sensitivity 61.1%) than macrometastases (sensitivity 84.0%, p< 0.001).
Conclusion: Intraoperative frozen section examination of the sentinel node is a useful predictor of axillary lymph node status in breast can-
cer patients. Seventy-two percent of the patients with metastatic disease were correctly diagnosed and spared a second surgical procedure.
? 2008 Elsevier Ltd. All rights reserved.
Keywords: Breast cancer; Sentinel lymph node; Frozen section; Intraoperative
Axillary nodal status has traditionally been the most
important factor in staging breast cancer. However, axillary
dissection can cause serious morbidity such as lymphe-
dema, impairment of shoulder function and paraesthe-
sia.1e3With improvements in breast cancer screening,
more patients are diagnosed with breast cancer at a stage
when nodal involvement is not yet present. Therefore, axil-
lary lymph node dissection (ALND) is no longer an accept-
able staging procedure. Instead, sentinel lymph node biopsy
(SLNB) is now used in most centres and has gained
acceptance as a predictor of axillary lymph node status
with a reported accuracy of 95e100%.4e6If the sentinel
node (SN) is positive and contains metastatic tumor cells,
13e60% of patients will have positive non-sentinel axillary
nodes4,6e9depending on the size of the metastasis. Patients
with metastatic involvement of the axillary nodes should be
offered ALND or radiotherapy for better locoregional con-
trol.10Although radiotherapy has shown some evidence of
survival benefit,11e13it is unlikely that surgical dissection
will provide any such benefit.10,14
By concomitantly performing intraoperative lymph node
biopsy and primary tumor resection, patients with a positive
sentinel lymph node are not subjected to the inconvenience
and risks of a second surgical procedure. Two techniques
are currently applied to assess the axillary nodal status in-
traoperatively: imprint cytology (IC) and frozen section
* Corresponding author. Tel.:þ31 26 3786909.
E-mail address: firstname.lastname@example.org (J.H.G. Klinkenbijl).
0748-7983/$ - see front matter ? 2008 Elsevier Ltd. All rights reserved.
Available online at www.sciencedirect.com
EJSO 35 (2009) 276e280
(FS) examination. Until now there has only been one large
series concerning intraoperative FS examination in breast
cancer patients.15In this article we present our findings
of a large series of FS examinations in patients with mam-
Patients and methods
Between January 2000 and December 2006, 759 consec-
utive patients with operable breast cancer who had been ad-
mitted to the Rijnstate Hospital, Arnhem, the Netherlands
underwent a SLNB. All procedures were performed by spe-
cialised surgeons with extensive experience in the field of
breast cancer surgery. One hundred and five patients partic-
ipated in trials without FS and received radiotherapy in the
event of a positive SN. Frozen sections were made in 654
patients. One patient had a malignant phyllodes tumor
and 38 patients had a ductal carcinoma in situ (DCIS) as
the primary tumor. Six hundred and fifteen patients had
an invasive primary tumor and comprised the study group.
Lymph node mapping
One day prior to the operation, lymphoscintigraphy was
performed after injecting99mTc-labeled nanocolloid peritu-
moral or subareolar in the patient’s breast. Scans of the in-
volved breast and axilla were acquired 2e3 h after tracer
injection. The SN was localized using patent blue injection
and a g-ray detection probe. Surgically excised sentinel no-
des were submitted fresh for FS. During pathologic exam-
ination of the SN, the surgical procedure continued and
mastectomy or wide local excision of the tumor was per-
formed. Subsequent axillary lymph node dissection was
performed when the SN revealed malignant cells.
Sentinel nodes with a diameter of less than 5 mm where
frozen intact, whereas SNs with a diameter of more than
5 mm were bisected longitudinally and frozen. Frozen sec-
tions of the sentinel node were taken from the optimal
cross-sectional surface with a microtome setting of 4 mm.
The remaining node tissue was fixed in 10% formalin and
embedded in paraffin, whereafter serial sections of 150 mm
were sampled and stained with both hematoxylineeosin
(H&E) (Waldeck GMBH & Co. KG, Mu ¨nster, Germany)
and immunohistochemical anticytokeratin CK8/cam 5.2
(IHC) (Becton Dickinson, Franklin Lakes, USA).
Metastases were classified as micrometastatic (?2 mm)
or macrometastatic (>2 mm). A combination of both was
classified as macrometastatic. Isolated tumor cells (ITC)
were defined as single tumor cells or small clusters of cells
(<0.2 mm). Sentinel nodes with ITC were regarded as neg-
ative and required no further treatment.
Comparisons were made using the Chi-square test or the
nificance was denoted as p< 0.05. The sensitivity (SE) and
accuracy were calculated with the following formulas: sensi-
tivity ¼(true-positive)/(true-positiveþ false-negative)
accuracy ¼(true-positiveþ true-negative)/(total number).
The patients ranged in age from 29 to 90 years (median
59.0 years). All but 2 of the 615 patients were female. Wide
local excision was performed in 445 patients, the remaining
170 underwent mastectomy. Median tumor size was 1.5 cm
and ranged from 0.1 to 10 cm. Tumor characteristics are de-
scribed in Table 1. The total number of lymph nodes found
in the SN specimens was 994 (mean 1.6 lymph nodes).
During the sentinel lymph node dissection (SLND), five no-
des could not be located and one specimen contained no
lymph node. As a result, these six patients had an ALND
during the same procedure.
Frozen section examination of the SN
Frozen section examination accurately diagnosed 90.7%
of the patients (Table 2). Of the 615 FS reports, 50 were
false-negative, yielding a SE of 71.6%. There were no
false-positive FS examinations ascertained. The sensitivity
Basic characteristics of the tumors
Histology invasive tumor
Histology non-invasive tumor
S. van de Vrande et al. / EJSO 35 (2009) 276e280
of the FS for tumor stage T1a/b, T1c and T2 or greater were
80.0%, 65.4% and 76.3%, respectively (Table 2). These re-
sults showed no significant relation between tumor size and
FS sensitivity. Sentinel node metastases were found with
macrometastases in 81 cases, micrometastases in 95 cases
and ITC in 16 cases (Table 3). ITC were only detected with
IHC staining. Frozen section investigation was less sensitive
in ascertaining micrometastases (SE 61.1%) than macrome-
tastases (SE 84.0%); (Table 3, p < 0.001). Patients with tu-
mor size T2 or greater were found to have relatively more
macrometastases in the FS specimen than patients with
smaller size tumors (T1a/b 8.6%, T1c 32.1% and T2/3
59.3%); (Table 4). Micrometastases in the FS specimen
were most common in T1c tumors (Table 4).
Axillary lymph node dissection
Of the 50 patients with false-negative frozen section re-
sults, 22 received subsequent ALND and 28 received axil-
lary radiation. Follow-up (range 2e72 months, mean 36.3
months) of all false-negative cases demonstrated no devel-
opment of local axillary recurrence. In 13 cases, the false-
negative SN showed macrometastases in the paraffin slide
and in 37 cases, the false-negative SN showed micrometa-
stases in the definite slide.
The treatment for 126 patients with a positive SN in the
FS specimen was ALND in 118 cases and radiation in the
remaining 8 cases (personal choice of the patient). When
the false-negative FS results are taken into consideration,
a total of 140 patients received ALND.
A total of 2118 axillary lymph nodes were dissected
(mean 14.3 axillary lymph nodes; range 5e32 axillary
lymph nodes). Seventy-nine ALNDs were negative, with
a mean of 21.9 and a range of 5e32 axillary lymph nodes.
Sixty-one ALNDs were positive, with a mean of 4.0 and
a range of 1e21 axillary lymph nodes. In up to 56.4% of
the 140 patients with an ALND, the SN was the only pos-
itive node. Sentinel node specimens with micrometastases
after H&E and IHC staining demonstrated a greater number
of negative ALNDs compared to macrometastases after SN
staining (64.2% versus 49.3%, respectively); (p < 0.001).
Intraoperative FS examination of the SN for tumor stag-
ing is worthwhile because it allows patients with SN metas-
tases, in this study 28% of the patients, to undergo
immediate ALND, thereby avoiding the need for a second
surgical intervention. The sensitivity and accuracy of FS
examination of the sentinel lymph node has been reported
to range from 36.0% to 93.3% and 83.2% to 96.0%, respec-
tively.4,16e22However, these studies differ considerably in
size, tumor characteristics, number of nodes sampled, num-
ber of frozen section slides taken and the staining procedure
utilized for the pathological examination.
Frozen section technique
Viale et al. examined the entire SN by subserially sec-
tioning the nodes at 50 mm intervals.23On each level, one
section was stained with H&E and the other section with
IHC. The majority (64.3%) of metastases were found in
the first pair of sections. This time consuming (up to
65 min) and expensive method revealed a SE of 93.3%.
In our study, all paraffin sections which were found to be
negative with H&E staining were re-examined with IHC
staining. The literature shows that the omission of this
Relation between T-status and the sensitivity of intraoperative frozen section of the sentinel node
Frozen section ?/(FN)
Frozen section þ/(FP)
Unknown Sensitivity (%)a
FN, false-negative and FP, false-positive.
Relation between metastases in the sentinel node and the sensitivity of
intraoperative frozen section of the sentinel node
Relation between T-status and metastases in the intraoperative frozen
section of the sentinel node
Total811384.0 95 3761.1
FN, false-negative and SE: sensitivity.
S. van de Vrande et al. / EJSO 35 (2009) 276e280
technique leads to an overestimation of FS sensitivity, be-
cause a substantial number of predominantly micrometasta-
ses will be overlooked. Schreiber et al. found 36% of all SN
metastases only with IHC staining.24Celebioglu and col-
leagues reported an improvement in SE from 73.5% to
83.7% when H&E staining was coalesced with IHC stain-
ing. However, the SE for macrometastases was already
100% for H&E staining only. Combining H&E with IHC
staining raised the SE from 45% to 55% for micrometasta-
ses. Yet, almost half of the cases with micrometastases were
not found during intraoperative FS examination.25
In our study, we removed 995 SNs with a mean of 1.6
nodes and a range of 0e6 nodes per SN procedure. The
literature shows that 98.0e99.6% of all metastases are
located within the first 3e4 nodes.26,27The reported num-
ber of false-negative FS biopsies of SNs is significantly
higher when only one node is harvested.
Frozen section examination versus imprint cytology
Another method to increase the SE and accuracy of FS in-
vestigation is through the utilization of imprint cytology (IC)
during the intraoperative analysis ofthe SN. Nagashimaet al.
found a major improvement in diagnostic performance by
combining these two techniques.17In reported series, the
SE and accuracy of the combination of these two techniques
was 73.6e82.6% and 93.2e96.0%,17,28respectively. The
inexpensive and simple technique that also conserves tissue.
The disadvantages of IC are the lack of details regarding
thenodalarchitecture and theinabilitytodeterminethedepth
yields few cells for examination andleads tomore intermedi-
ate results. The SE and accuracy of IC of the SN, as a single
technique, has been reported to range from 54.0% to 97.3%
and 82.0% to 98.2%,17,19,20,29e31respectively. However, sev-
eral studies have reported cases of intraoperative false-posi-
tive IC. As a consequence hereof, patients would receive
Relation between T-status and SE
In our study, T1a/b tumors showed the greatest SE of FS
examination. However, we found no significant difference
between the SE in T1a/b, T1c and T2/3 tumors. We can ex-
plain this finding by the small number of metastases found
with T1a/b tumors compared to T1c and T2/3 tumors
(Table 4). Nevertheless, Weiser and colleagues found a sig-
nificant increase of FS sensitivity with the tumor size.15
Patients with T2/3 tumors benefited the most from FS in-
vestigation of the SN (Table 4).
The need for an axillary staging procedure in patients
with small (<1 cm) tumors remains controversial. Several
studies suggest that an axillary staging procedure can be
omitted in clinically node-negative patients with non-
high-grade small tumors.34,35Nevertheless, Cserni et al.
reported a SN involvement of >10% in tumors ranging
from 5 to 15 mm in greatest dimension, thereby indicating
the need for axillary lymph node staging.36
Routine axillary surgery should not be performed in pa-
tients with DCIS due to their low axillary nodal involve-
ment.36e38We therefore omitted 38 patients from our study
with grade III DCIS, who received a SN biopsy in our centre.
None of these patients had a positive SN after SLNB.
Relation between metastases size and SE
This study has revealed that the SE of FS examination
was significantly greater when the SN contained macrome-
tastases compared to micrometastases (84.0% versus
61.1%, respectively; p < 0.001). This demonstrates that
false-negative results are due to the failure of micrometa-
static detection. Nonetheless, the prognostic significance
of these metastases remains controversial. Recent studies
have shown that less than 15% of patients with micrometa-
static involvement of the SN had tumor deposits in the
non-SNs.7,39e41In the present study, ITC were onlydetected
with IHC staining. Patients with ITC did not receive ALND
in our hospital, since any benefit from this procedure can
only be expected in patients with micro- or macrometastatic
involvement of the axilla.36,42e44As of December 2006, not
houn et al. recently demonstrated that less than 5% of pa-
tients with ITC-positive SNs had non-SN containing tumor
deposits.42In contrast, macrometastatic SNs are associated
with a high rate of non-SN involvement. In our study, the
non-SNs of patients with macrometastases in the SN after
staining, were significantly more likely to contain tumor de-
posits than the non-SNs of patients with micrometastases
(60.7% versus 39.3%, respectively; p < 0.001).
Based on the available data, it appears that intraopera-
tive FS examination of the SN is a useful predictor of axil-
lary lymph node status in breast cancer patients. The
majority of node-positive cases allows for immediate
ALND in a one-stage surgical procedure.
Conflict of interest
The authors declare that there is no conflict of interest.
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