NEW ORLEANSPreoperative lymphoscintigraphy can be used to
identify women with primary breast cancer who have multidirectional
lymphatic drainage. This appears to occur in about 10% of breast
cancer patients, who can then have these areas dissected or included
in radiation ports.
Findings from a large prospective study, funded by the US Department
of Defense, were presented at the Society of Surgical Oncology (SSO)
Elizabeth Dupont, MD, of H. Lee Moffitt Cancer Center, Tampa, said
that the study included more than 500 breast cancer patients from 41 institutions.
She said that the study was initiated to define the role of
preoperative lymphatic mapping combined with intraoperative imaging
in identifying extra-axillary drainage.
We sought to identify a subgroup of patients who showed no
lymph drainage to the axillae and, therefore, might not require an
axillary staging procedure, but we were not reliably able to do
so, Dr. Dupont said.
Lymphoscintigraphy has been an important diagnostic tool in melanoma,
but has not been used routinely in breast cancer, since most
surgeons have been concerned only with mapping to the axillae,
she pointed out.
The researchers felt that preoperative lymphoscintigraphy might
identify a subset of women with extra-axillary drainage, serve as an
adjunct to sentinel lymph node (SLN) biopsy, and provide information
about numbers and location of nodes to be harvested.
Preoperative lymphoscintigraphy images were produced using filtered
technetium-99 sulfur colloid, and lymphatic drainage to the axillary
and internal mammary nodes was noted. Intraoperatively, a hand-held
gamma probe was used to identify the sentinel lymph nodes. Most
patients then underwent axillary node dissection at levels 1 and 2.
Drainage to an axillary sentinel lymph node was found in 336 patients
(65%). No axillary nodes were shown preoperatively in 181 patients
(35%), who were then taken to the operating room for intraoperative mapping.
At this point, 52 patients (10% of all patients imaged
preoperatively) demonstrated an extra-axillary node, such as an
internal mammary node; 45 of these patients showed bidirectional
drainage to the axillae and internal mammary sites, and 7 drained
only to the internal mammary, Dr. Dupont reported.
Although lymphoscintigraphy was unable to identify a sentinel lymph
node in 181 patients, 153 (85%) of these patients had an axillary
sentinel lymph node identified with intraoperative mapping using the
sensitive hand-held gamma probe and vital blue dye.
were 28 patients who failed to map either preoperatively or
intraoperatively, Dr. Dupont said. Thirteen of these patients (47%)
were found to have metastatic disease in the axillae upon complete
axillary node dissection.
Nearly half of these patients had more than one positive node. Some
had extensive positive nodes, such as extranodal extension or, in one
case, positivity in all 25 nodes dissected.
Four of the 13 had palpable tumors, and 6 patients had undergone
previous excisional biopsy. In each of these 13 cases, there had been
no massage with injection of the imaging agent, which might have
improved mapping success, Dr. Dupont said. (See Table 1 for factors
that may decrease success and Table 2 for factors that may improve success.)
In the majority of image-negative patients, sentinel lymph
nodes were still identified intraoperatively. Patients who had
negative imaging and no dye or radiocolloid in the axillae still need
level 1 or 2 node dissection, as 47% will have metastatic
disease, she said.
Dr. Dupont concluded, We showed through lymphoscintigraphy that
drainage is variable and
there may be multiple routes, which is important in decision-making
Treatment varied for the subset of patients with multidirectional
drainage. Some of our institutions chose to observe nodes;
others included them in radiation ports of breast-conserved patients;
others removed them, she said. How to best handle this
subset needs to be addressed in national trials.
David Craig, MD, of the University of Vermont, commented, This
is a large trial, and we have to pay attention to it. Gamma camera
imaging identifies extra-axillary nodes, but if you rely solely on
the gamma camera, you are going to miss SLNs. However, SLNs not seen
by the gamma camera are generally detected by hand-held probes. Our
challenge is to apply all of our tools to these new problems.