NEW ORLEANSPathologic examination of an intraoperative frozen
section of the sentinel lymph node (SLN) is less sensitive for breast
cancer patients with smaller tumors and/or micrometa-static disease.
In a recent study, use of routine frozen section avoided reoperation
in only 4% of patients with T1a cancers, but was more useful in other
stages, reported Martin R. Weiser, MD, of Memorial Sloan-Kettering
Pathologic examination of a biopsied sentinel lymph node during
surgery may avoid a second operation if the results are positive. But
this report indicated the method is not accurate for all patients.
At the Society of Surgical Oncology Cancer Symposium, Dr. Weiser
presented the results of a large Memorial Sloan-Kettering study.
Sentinel lymph node biopsy and intraoperative frozen section analysis
were performed in 890 of 1,000 consecutive patients with invasive
breast cancer. The results were matched against the outcomes of
enhanced pathologic analysis with serial sections of nonfrozen
samples from the same patients.
The study found that 231 patients (26%) had SLN metastases, and 58%
of these were diagnosed with intraoperative frozen section analysis.
But the sensitivity of the frozen section was related to the size of
the metastatic deposit.
The method yielded good results with SLN macrometastases (greater
than 2 mm), finding 92%. But it did not perform well in the case of
micrometastases (2 mm or smaller), correctly identifying only 23% of
these. The difference by lesion size was significant (P < .001),
Dr. Weiser reported.
If we look at just those patients with macrometastatic SLN
deposits, we see that the sensitivity of intraoperative frozen
section is quite high in all categories and is, in fact, independent
of the tumor stage. And if we look at only those patients with
micrometastatic SLN deposits, we see that the sensitivity of frozen
section is low in all groups and is also independent of primary tumor
stage, he said.
As patients move from stage T1a to T2, the proportion of patients
with mac-rometastatic disease increases, and this is paralleled by an
increase also in frozen section sensitivity (Table). Patients with
T1a tumors mostly had micrometastatic deposits that were missed by
frozen section, whereas patients with T2 disease mostly had
macrometastatic deposits that were picked up by frozen section, he
Indications for Frozen Section
Dr. Weiser said, Routine sentinel node frozen section is
indicated in all patients with T2 breast cancers, since 38% of these
patients would avoid a reoperation for completion of axillary
dissection. But in patients with T1a lesions, frozen sections may not
be indicated, since only 4% will benefit from the avoidance of
reoperation, he said.
Patients with T1b or T1c lesions have a 10% to 16% benefit for
avoidance of reoperation, and further cost-benefit analysis is
warranted in this group, he said. Ultimately, the benefit is
relative and should be determined by the expectation of the patient
and the surgeon, who will have to determine the acceptable rate of
reoperation, he said.
Commented Michael J. Edwards, MD, professor of surgery, University of
Louisville (Kentucky), This study tells us that if you have
smaller tumors, the frozen section is less likely to be sensitive.
The only question then becomes what to do with this information.
Dr. Edwards departed slightly from Dr. Weisers position on the
T1a category of patients. I would say that frozen sections
dont cost the patient much besides money. You are identifying 4
out of 100 women who dont have to return to the operating room
for these small T1a lesions, which seems logical from a cost analysis
standpoint, he said.