A quick method of testing for the presence of melanoma skin cancer cells in special lymph nodes called ’sentinel lymph nodes,’ developed at the Medical College of Wisconsin, allows surgeons to get results while the patient is still on the operating table. In most cases, this will eliminate the need for a second operation in cases where additional local lymph nodes - called ‘regional lymph nodes’ - must be removed.

The “MCW Melanoma Cocktail” reveals with much higher accuracy than conventional methods whether cancer cells of melanoma have spread to the “sentinel” lymph node, the first lymph node to be affected. The test is conducted during the interval between two standard surgeries performed on melanoma patients, the sentinel lymph node biopsy and the wide excision of the biopsy site to remove the melanoma.

“The MCW Melanoma Cocktail was developed about four years ago and it has been used as a routine protocol since then,” said Vinod Shidham, MD, FIAC, MRCPath, Medical College Associate Professor of Pathology. “Before that we were using other immunomarker antibodies, and those were not giving good results.” Dr. Shidham is Executive Editor and Editor-in-Chief of the online research publication Cytojournal and Director of Fine Needle Aspiration Biopsy Service and Cytopathology Fellowship Training Program at Froedtert and Medical College

Antibodies are used in biopsies to stain certain cells so that they stand out under the microscope. The antibodies change the color of the cells so that cancer cells can be identified in the vast sea of normal cells, and the MCW Melanoma Cocktail has shown good results in staining just the melanoma cells and providing a very clean picture for the interpreting pathologist and accurate results for the surgeon.

Accuracy and Speed

“At many places people are still using the other markers, but those are difficult to read and result in problems interpreting some cases, said Dr. Shidham. “That’s the reason we came up with this alternative. The cocktail has three components, what we call MART-1, Melan-A and tyrosinase. To perform all three individually is more expensive, takes more time, and makes reading results more challenging.”

“So what I did was combine them and make a ‘cocktail’ of them in a standardized pattern. “We get the lymph node when the patient is still on the operating table, we make a smear from that lymph node, and we stain that with the MCW Melanoma Cocktail. Melanoma has its own marker, and we add on antibodies that combine with that marker. Wherever those antibodies go there is a molecule that generates a color. If it is a melanoma cell, it will look brown.”

Incidence of melanoma in the US has more than doubled in the past 20 years. It is the most deadly of skin cancers, and according to the American Cancer Society more than 55,000 new cases of melanoma will develop in 2004, with nearly 8,000 deaths.

Patients evaluated by routine protocol must wait 24 to 48 hours or longer for results of sentinel lymph node biopsy to come back from a lab. If the test shows that cancer has spread to the sentinel lymph node, an additional operation is performed at a later date to remove the regional nodes to which the melanoma drains. The MCW Melanoma Cocktail gives results in about 30 minutes after the initial sentinel lymph node biopsy operation.

Study Results Promising

A Medical College study evaluated MCW Melanoma Cocktail biopsies from patients at Froedtert Hospital and revealed a high degree of accuracy. The study’s co-investigators were Associate Professor of Plastic Surgery William W. Dzwierzynski, MD, and Associate Professor of Dermatology Marcelle Neuburg, MD. “We decided that if we could tell during the first operation, then the surgeon can go ahead with the removal of the patient’s regional lymph nodes during the same anesthesia, so the patient doesn’t have to go through a second round of anesthesia, pain and complications,” said Dr. Shidham. “It saves a lot of time and money, too. All those things are beneficial.

“If the cells are there, the physician goes ahead with the second operation during the same surgery,” said Dr. Shidham. “Usually the surgeon has already explained to the patient that if something is there they will proceed with the operation.”

Dr. Shidham stressed that early detection is still the key to treatment of melanoma. The disease originates in pigment producing cells of the skin, and unlike other skin cancers it spreads very rapidly through the lymph nodes.

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