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Introduction

The concept of identifying and localizing the sentinel node or nodes before biopsy is that these nodes receive initial lymphatic drainage and are the first filter to remove metastatic cells; thus, if this sentinel node is free of disease, the rest of the nodes in the patient will also be free of disease. Three methods (along with marking of the skin) are used: (1) lymphoscintigraphy (preoperative), (2) nuclear probe localization (intraoperative), and (3) blue dye injection (intraoperative). Often, all three techniques are used together, the lymph nuclear scan being the most common (see Procedures).

These special prebiopsy procedures are done before biopsies to diagnose cancer of breast or melanoma. Indications for lymph nuclear scan lymphoscintigraphy include detection of metastasis, mapping of all sentinel nodes, and staging and monitoring cancers such as melanoma, breast, head, neck, and skin. Indications for using the nuclear gamma-radiation probe include detecting the most sentinel nodes and providing auditory confirmation. See Chapter 9 for more information on nuclear scans. Indications for blue dye staining include to provide visual confirmation of nodes and to map tumor route (urine will turn blue and skin will stain).

Procedure

  1. Lymph nuclear scan (lymphoscintigraphy):

    1. For the breast, inject the radiopharmaceutical (large volume) subcutaneously into the breast and adjacent to suspected breast tumor; for lymphedema, inject into webs of fingers and toes.

    2. For melanoma, make four to six intradermal injections around the tumor or excision site, avoiding scar tissue.

    3. Perform immediate imaging with the patient in the position expected during surgery.

  2. Nuclear radiation (gamma) probe:

    1. A previously administered radiopharmaceutical and the sound radiation detector permit node detection and localization to determine where the initial operative incisions can be made.

    2. Use the sound-radiation gamma probe to locate the area of radioactivity not associated with the injection sites. Of the three procedures, the probe is the most sensitive.

  3. Blue dye:

    1. In order to identify the nodes to undergo biopsy, inject the feet in the web between the toes and the hands between the second and third fingers (allergic reaction to the dye may occur).

    2. Operative biopsy procedure may follow this test.

Procedural Alert

Only when the sentinel node is positive is a complete nodal dissection performed

Clinical Implications

  1. Abnormal findings reveal metastatic nodes and routes of spread.

  2. Asymmetry may indicate lymph flow obstruction.

Interventions

Pretest Patient Care

  1. Explain purpose of sentinel node identification procedures.

  2. Inform the patient that if the results are positive, surgery usually follows soon after.

Intratest Patient Care

  1. Be aware that sedation or analgesia is not usually ordered.

  2. Mark the site of lymph nodes with indelible marker.

  3. Provide support, assist with positioning, and provide reassurance to the patient that testing is proceeding as expected.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Monitor injection site (breast, toes, fingers, or around tumor excision site). Check for signs of inflammation or bleeding.

  2. If surgery is planned, prepare according to established protocol. Also, see Biopsy Studies Overview section.

  3. When surgery is scheduled, take images just before transfer to the operating room.

  4. Counsel about outcomes and possible need for further testing or treatment.

Reference Values

Normal

No evidence of tumor activity

No blocked lymphatic drainage