Biopsy of sentinel lymph node for penile cancer Medical editor Bjørn Brennhovd MD
Oslo University Hospital
A sentinel node is the first lymph node the cancer cells metastasize to. At the biopsy, the sentinel node is resected and examined for pathology. If lymph node metastases are not deceted by light microscopy, an immunohistochemistry is perfomed to exclude sub- micrometastases. If there is no metastasis, the surgeon will limit the operation as if there is not tumor spreading (N0).
Dynamic sentinel node staging
In dynamic sentinel node staging, radioactive istopes are injected into the base of the primary tumor. The isotopes are then transported in the lymphatic system from the tumor to the first lymph node where they gather. This lymph node is identified with a gamma camera and peroperatively with a gamma detector. The sentinel node can be resected via a small incision.
The benefit of dynamic sentinel node staging is that the morbidity is low for the operative procedure. It is assumed that the sensibility and specificity is also higher than in anatomical sentinel node staging.
A close cooperation between the department of nuclear medicine and the surgeon is neccessary.
- Examine for lymph node metastasis.
- One hour before the radioactive isotope is injected, Emla® is applied to the skin where the injection will be made.
- Usual preparations for the operation day.
The injection is performed at the department of nuclear medicine in the morning of the operation day.
- The patient lies in the supine position.
- 99m Tc-labeled colloidal human albumin is injected into the base of the tumor.
- Images are taken after 30 minutes with a gamma camera to localize radioactivity in the nodes.
In the operating theater
- A gamma camera is used for precise preoperative localization of the sentinel node.
- A small incision is made in the skin over the node.
- The node is retrieved through the incision.
- The skin is sutured with absorbable sutures.
- The node is sent unfixed for frozen sectioning to the pathologist.
- Allergic reactions to human albumin can occur.
- Otherwise, the usual postoperative observations apply.