32 2011
IMAGING & ONCOLOGY
SENTINEL NODE
Figure 1. Lymph node location for breast cancer. An anterolateral view of the right breast. Illustra- tion depicting cancer in glandular tissue and lymph nodes of the breast. Courtesy of Medical RF / Phototake
http://www.phototakeusa.com/results.asp?Image=ZEME027027775-01 Accessed January 2011. Annotated by the authors.
PRIMARY TUMOUR
Histology results achieved from SLNB have been used to plan surgery for a range of cancers, including breast, producing an optimal method for reducing morbidity in the node negative portion of the prevalent population7 would lead to node removal.
. Evidence of nodal metastatic spread
LOCATING THE SENTINEL NODE Ultrasound can be used to locate sentinel nodes, but when used alone it is inhibited by an inability to confidently establish whether a lymph node is sentinel (first in the lymphatic chain) or not. A more suitable role for ultrasound is in guiding lymph node fine needle aspiration (FNA) or core biopsy, and is standard in some countries. This method has been shown to have good correlation with histological results of surgically removed nodes8
. Ultrasound does, of course, have the benefits of no radiation burden, low
cost and good availability, helping to maintain the established role it holds in the management of nodal involvement in cancer.
A variety of techniques for localising the sentinel node in relation to breast cancer exist in current practice, using various combinations of the following methods: • ‘Blue dye’ injection intra-operatively • Nuclear medicine 99 • Nuclear medicine 99 • Nuclear medicine 99 • Nuclear medicine 99
Tcm Tcm
Tcm Tcm -colloid + planar imaging
-colloid + planar imaging + SPECT -colloid + planar imaging + SPECT/CT -colloid (No images acquired)
• Intra-operative gamma probe
The combination of blue dye, initially introduced for identifying the sentinel node in patients with malignant melanoma9
, and a radionuclide injection have proved to be
optimal for sentinel node identification, showing great success in guiding surgeons in intra-operative biopsy (prior to histology), node dissection and surgical resection.
Despite the advantage of a visual stimulus provided by the blue dye, there was still no indication that the node was sentinel. Consequently, a non-imaging radionuclide technique was introduced to aid localisation and it became apparent that the two techniques were complementary10
and successful in 81-100% of cases of melanoma11
Pre-operative sentinel node evaluation allows biopsy, followed by histology. Intra- operative evaluation allows biopsy (± excision) with histology results returned during the procedure. In both cases histology results dictate whether the node is removed.
Pre-operative localisation gives surgeons accurate numbers and locations of nodes, with the potential to perform less invasive surgery because less exploration is required. Operating time can also be reduced, which in turn may reduce complications and improve throughput of patients.
.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72