Sentinel lymph node biopsy has replaced axillary dissection for axillary staging in clinically node negative breast cancer patients [
On the day of surgery, a nuclear medicine technologist delivers a lead case to the operating room containing 0.25–0.5 mCi of technetium-99m sulfur colloid in a 0.4 mL volume. After induction of general anesthesia, the radioactive tracer is infiltrated intradermally as a skin wheal directly over the breast cancer site or injected into the subdermal plexus of the areola. In rare circumstances in which there is a scar between the areola and the axilla, the radioisotope is injected lateral to the scar so as to avoid interference from scar tissue (see Figure
Intradermal injection of Tc-99m above excisional biopsy scar.
The licensed nuclear radiology attending physician authorizes release of technetium for intraoperative injection. The surgeons have received instruction on how to properly handle the isotope. For each case where SLNB is scheduled, nuclear medicine staff delivers Tc-99m sulfur colloid in a lead box from the department of nuclear medicine to the appropriate operating room. The surgeon then carefully injects the Tc-99m sulfur colloid while wearing gloves and eye protection. The empty syringe, needle, and any gauze or alcohol wipes that come into contact with the isotope are immediately placed back into the lead box, which is then taken back to the nuclear medicine department for proper disposal. A radiation safety officer is available at all times for questions or to respond to spills. To date, there have been no radioactive spills in the operating room or any inappropriate disposal of radioactive waste. Surgeons and OR staff are not required to wear radioactive monitoring badges given the limited exposure.
The Breast Center maintains a prospectively collected database which contains data on all patients undergoing oncologic breast surgery. After approval by the Yale University Human Investigations Committee (HIC), patient deidentified data was abstracted from this database on all patients undergoing a sentinel lymph node biopsy for breast cancer between 2003 and 2014. Demographic data collected included patient age, ethnicity, cancer histology, molecular subtype, TNM stage, and breast surgical procedure, and endpoints collected included the number of sentinel lymph nodes obtained, number of positive sentinel lymph nodes, number of nonsentinel lymph nodes obtained, and number of positive nonsentinel lymph nodes. Because the data was merely descriptive, no statistical comparisons were needed.
There were 2,333 patients in the database who underwent a sentinel lymph node biopsy. All patients had radioisotope injection of technetium-99m sulfur colloid and approximately 56% of cases had dual tracer with both the radioisotope and blue dye. During the early part of the time period, there were 5 additional cases where a sentinel node biopsy was attempted but no node was found, for an identification rate of 99.8%. All of the five cases where a node was not found had an extensive scar between the injection site and the axilla. This leads to our current practice of injecting the isotope in a location to avoid interference with a surgical scar. We also had a number of cases where a second sentinel node biopsy was performed after a previous sentinel node biopsy, but these cases were excluded from this analysis.
The patient demographics for all 2,333 patients are shown in Table
Demographic data.
Frequency | Percent | |
---|---|---|
|
||
Caucasian | 1,874 | 80.3 |
Black | 222 | 9.5 |
Hispanic | 113 | 4.8 |
Asian | 66 | 2.8 |
Other | 58 | 2.5 |
|
||
<30 | 22 | 0.9 |
31–40 | 164 | 7 |
41–50 | 608 | 26.1 |
51–60 | 649 | 27.8 |
61–70 | 553 | 23.7 |
>71 | 337 | 14.4 |
|
||
Infiltrating ductal | 1,573 | 67.4 |
Infiltrating lobular | 242 | 10.4 |
Mixed ductal and lobular | 137 | 5.9 |
Ductal carcinoma in situ | 253 | 10.8 |
Other | 128 | 5.5 |
|
||
ER/PR positive, Her-2 negative | 1,494 | 64 |
ER/PR positive, Her-2 positive | 160 | 6.9 |
ER/PR negative, Her-2 positive | 102 | 4.4 |
ER/PR negative, Her-2 negative | 243 | 10.4 |
|
||
0 | 253 | 10.8 |
1 | 1,366 | 58.6 |
2 | 592 | 25.4 |
3 | 111 | 4.8 |
4 | 11 | 0.5 |
|
||
Well differentiated | 499 | 21.4 |
Moderately differentiated | 1,110 | 47.6 |
Poorly differentiated | 557 | 23.9 |
|
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Partial mastectomy | 1,277 | 54.7 |
Mastectomy (including bilateral, simple, and modified radical) | 1,056 | 45.3 |
The median number of sentinel nodes obtained was 2 and the mean number was 2.33 with a range of 1–15 nodes. About a third of cases had only one sentinel lymph node removed, a third had 2, and a third had 3 or more (Table
Sentinel lymph nodes obtained.
Frequency | Percent | |
---|---|---|
1 | 779 | 33.4 |
2 | 754 | 32.3 |
≥3 | 800 | 34.3 |
Total | 2,333 | 100 |
Positive sentinel lymph nodes.
Frequency | Percent | |
---|---|---|
0 | 1,821 | 78.1 |
1 | 365 | 15.6 |
2 | 101 | 4.3 |
≥3 | 46 | 2 |
Total | 2,333 | 100 |
Positive sentinel lymph nodes by histology.
Invasive carcinoma | Ductal carcinoma in situ | |
---|---|---|
0 | 1,569 (75.4%) | 252 (99.6%) |
1 | 365 (17.5%) | 0 (0%) |
2 | 100 (4.8%) | 1 (0.4%) |
≥3 | 46 (2.2%) | 0 (0%) |
Total | 2,080 | 253 |
Table
Nonsentinel lymph nodes obtained in sentinel lymph node positive patients.
Nonsentinel lymph nodes | Frequency | Percent |
---|---|---|
0 | 87 | 16.3 |
1–10 | 203 | 38 |
11–20 | 199 | 37.4 |
21–30 | 68 | 7.8 |
31–39 | 4 | 0.8 |
Positive nonsentinel lymph nodes following positive sentinel lymph node biopsy.
Positive nonsentinel lymph nodes | Cases with a positive sentinel lymph node | Percent |
---|---|---|
0 | 242 | 54.2 |
1 | 65 | 14.5 |
2 | 42 | 9.4 |
3 | 22 | 4.9 |
4 | 17 | 3.8 |
5–10 | 38 | 8.4 |
11–20 | 15 | 3.2 |
21–29 | 6 | 1.2 |
Although historically an axillary lymph node dissection was performed to stage the axilla, compared to sentinel lymph node biopsy, there was increased morbidity including lymphedema, nerve disruption, chronic shoulder pain, weakness, and joint dysfunction. As a result, sentinel lymph node biopsy has become standard of care to allow for proper axillary lymph node staging [
With the speed of lymph node localization provided by intradermal and subareolar injection [
The benefits of intraoperative injection in our experience include both patient and surgeon related factors as outlined in Box
(1) Patient factors (i) Decreased discomfort as patient is under anesthesia (ii) Improved logistics as patient does not need to go to nuclear medicine (2) Surgeon factors (i) Can have a first case start time and no case delay due to nuclear medicine schedule
It is important to point out that intraoperative injection requires collaboration between the surgeons and nuclear radiologists. Ultimately the nuclear radiologist bears the responsibility for the safe use of the isotopes. From a radiation safety standpoint, Miner et al. [
We are not advocating that intraoperative injection should become a standard of care that is used everywhere. Perhaps at institutions with a large number of low volume breast surgeons, intraoperative injection may not be feasible. Each institution should decide what works best for its particular situation. However, at Yale, with a small number of high volume breast surgeons, intraoperative injection works very well.
In our long-term, prospective experience, intraoperative injection of the radioisotope, technetium-99m sulfur colloid is convenient, effective, safe, and comfortable for the patient. The sentinel lymph node detection rate was essentially 100%.
The authors declare that there are no conflicts of interest regarding the publication of this paper.