Patent Awarded For New Procedure To Detect Cancer Spread

Main Category: Breast Cancer
Also Included In: Radiology / Nuclear Medicine
Article Date: 25 Jun 2008 - 1:00 PDT

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Eugene A. Woltering, MD, FACS, The James D. Rives Professor of Surgery and Chief of the Sections of Surgical Oncology & Endocrine Surgery at LSU Health Sciences Center New Orleans, has been awarded a US Patent for a one-step method to rapidly identify "sentinel nodes;" the lymph nodes most likely to contain early metastasis from a primary cancer. Preliminary research indicates that the procedure which consists of injection of a radiolabeled dye around a cancer can identify sentinel nodes that receive lymphatic drainage from the tumor within 10 minutes.

Dr. Woltering's patent is based on linking a radioactive iodine molecule to the blue dye commonly used in these sentinel node procedures. One of the major ways to determining the prognosis of a cancer involves determining whether the cancer has metastasized into other areas of the body. As lymphatic fluid flows from the primary tumor, the lymph fluid flows through lymph channels and then into lymph nodes where it often begins to multiply and grow. The first lymph node that is reached by the lymphatic fluid as it drains from the tumor region is called the sentinel lymph node. The sentinel lymph nodes for breast tumors are usually found in the axilla, or armpit.. A tumor may have one or more sentinel lymph nodes.

In contrast to the current two-step sentinel node mapping process, Dr. Woltering's method involves injecting 125I-labeled methylene blue, mixed with an unlabeled dye to determine the location of the sentinel lymph nodes in or near the tumor or tumor site utilizing a hand held Geiger counter -like device. Within about 10 minutes, enough of the dye has accumulated in sentinel nodes to be visible with the naked eye, or detectable using a radiation- detecting device called a gamma probe.

A sentinel lymph node biopsy is used to determine whether all lymph nodes in the drainage area must be removed. This procedure depends upon an effective technique for identifying the sentinel lymph node. If the cancer has spread to the sentinel lymph nodes, the surgeon will then remove all lymph nodes in the region. If the sentinel lymph node is found to be cancer free; all other nodes of the same area are generally cancer-free. The accurate identification and biopsy of the sentinel lymph node (when pathologically negative) means that other nodes will not be removed. The retention of normal lymph nodes benefits the patient by preventing lymphatic fluid accumulation in the arm or other extremity.

Dr. Woltering's new method can be used with solid tumors from a number of cancers including melanoma, breast cancer, head and neck cancers, lung cancer, neuroendocrine cancers, squamous carcinoma and colorectal cancer. The current techniques for identifying the sentinel lymph node involve the use of a radioactive colloid compound, a vital dye, or both. When both a dye and a radiolabeled carrier are used, they have been injected separately. The radiolabeled carrier substance is injected either the afternoon prior to surgery or the morning of surgery while the patient is awake.

Dr. Woltering notes that "many patients consider the injection of the radiolabeled colloid carrier as painful as childbirth."

"This may be the most valuable part of our invention," says Woltering. "It prevents women from having a painful, scary procedure while they are awake and substitutes an equally effective injection performed while they are sedated or asleep."

The usual interval from radioactive injection until surgery is 2-4 hours and with the increasing demand for sentinel lymph node sampling, surgeons have been forced to deal with major delays in surgical schedules.

Next steps along the road to FDA approval of this novel radioactive drug include a Phase II clinical trial to be conducted at University Medical Center in Lafayette, LA.

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Source: Leslie Capo
Louisiana State University Health Science Center

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