Sentinel Node Biopsy Technique for Breast Cancer (see diagram)

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lymphoscintography injected into breast (7:00 lesion) draining into right axilla nodes (A) and internal mammary nodes (B)

blue dye stain identifies the sentinel node

Rather than performing a routine axillary lymph node dissection, some women may be candidates for a more selective sentinel node dissection (see NCCN, some women may not need any axilla node sampling see NCCN.) A sentinel lymph node is the first lymph node to receive lymphatic drainage from a tumor. It can be detected by injection of a blue dye or radioactive colloid around the primary tumor, which travels to and identifies the first draining (sentinel) node. (see picture on left and here). Biopsy of a sentinel lymph node can reveal whether there are lymphatic metastases, thereby obviating the need for extensive dissection of the regional lymph-node basin.

Generally if the sentinel node is negative no further surgery is necessary. If the sentinel nodes show cancer then generally the rest of the level 1 and 2 nodes are removed. Recent studies (ACOSG Z11 trial)  have shown that it may not be necessary to remove these nodes (go here).

 

Because the tumor status of the regional lymph nodes is the most important prognostic factor in patients with early-stage breast cancer, accurate histopathologic assessment of these nodes is essential for optimal management, including the selection of candidates for adjuvant systemic therapies. Intraoperative lymphatic mapping using a vital blue dye, with or without a radiocolloid, can identify the first axillary node to receive lymphatic drainage from a primary breast carcinoma. Focused histopathologic assessment of this sentinel node can be used to determine the tumor status of the entire axillary basin.

The minimal morbidity and high accuracy of sentinel lymph node dissection (SLND) in breast cancer have been validated by multiple independent investigators, and the data suggest that this surgical technique may eventually replace complete lymph node dissection as the preferred axillary procedure for the management of early-stage disease. In experienced hands, SLND can be successfully performed in more than 90% of eligible breast cancer patients; the tumor status of the sentinel node accurately predicts the status of all axillary nodes in more than 95% of cases.

This article reviews the current status, controversies, and future directions of SLND as a staging technique for patients with primary breast carcinoma.  here, and Cancer Control 2001;8:408)

 

The Sentinel Node in Breast Cancer -- A Multicenter Validation Study

David Krag, Donald Weaver, Takamaru Ashikaga, Frederick Moffat, V. Suzanne Klimberg, Craig Shriver, Sheldon Feldman, Roberto Kusminsky, Michele Gadd, Joseph Kuhn, Seth Harlow, Peter Beitsch, Pat Whitworth, Jr., Roger Foster, Jr., Kambiz Dowlatshahi

Background. Pilot studies indicate that probe-guided resection of radioactive sentinel nodes (the first nodes that receive drainage from tumors) can identify regional metastases in patients with breast cancer. To confirm this finding, we conducted a multicenter study of the method as used by 11 surgeons in a variety of practice settings.

Methods. We enrolled 443 patients with breast cancer. The technique involved the injection of 4 ml of technetium-99m sulfur colloid (1 mCi [37 MBq]) into the breast around the tumor or biopsy cavity. "Hot spots" representing underlying sentinel nodes were identified with a gamma probe. Sentinel nodes subjacent to hot spots were removed. All patients underwent a complete axillary lymphadenectomy.

Results. The overall rate of identification of hot spots was 93 percent (in 413 of 443 patients). The pathological status of the sentinel nodes was compared with that of the remaining axillary nodes. The accuracy of the sentinel nodes with respect to the positive or negative status of the axillary nodes was 97 percent (392 of 405); the specificity of the method was 100 percent, the positive predictive value was 100 percent, the negative predictive value was 96 percent (291 of 304), and the sensitivity was 89 percent (101 of 114). The sentinel nodes were outside the axilla in 8 percent of cases and outside of level 1 nodes in 11 percent of cases. Three percent of positive sentinel nodes were in nonaxillary locations.

Conclusions. Biopsy of sentinel nodes can predict the presence or absence of axillary-node metastases in patients with breast cancer. However, the procedure can be technically challenging, and the success rate varies according to the surgeon and the characteristics of the patient. (N Engl J Med 1998;339:941-6.)

Positive Sentinel Node Biopsy
(Cox in Ann Rev Med 2000;51:525)
Tumor Size Positive Sentinel Nodes
T0 (DCIS) 9%
T1a (5mm) 18.8%
T1b (5.1 - 10mm) 19.7%
T1c (10.1 - 20mm) 31.9%
T2 (2 - 5cm) 53.5%
T3 (over 5 cm) 88.9%

1

Arm Morbidity in ALMANAC Trial - 2005
  Sentinel Node Standard Dissection
Numbness at 6 months 14% 37%
Arm Swelling at 6 months    
     mild 4% 14%
     moderate-severe 0.5% 3%
 

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