Using an ultrasound-guided fine needle to biopsy lymph nodes could spare thousands of melanoma patients every year worldwide from having to undergo unnecessary and sometimes unpleasant surgery to verify whether their cancer has spread, new research indicates.
In a study presented at the European Cancer Conference (ECCO 14) in Barcelona, scientists found that the less invasive technique produced a false positive rate of only one percent, so that 99 percent of patients with healthy lymph nodes were correctly classified.
The study, the largest of its kind to date, tested the accuracy of the new technique in 590 patients with recently diagnosed melanoma who underwent an ultrasound of the lymph node region near their tumours before having the sentinel lymph node cut out for examination. If the ultrasound confirmed cancer or looked suspicious, patients also underwent the fine needle aspiration biopsy before the sentinel node surgery. Survival was tracked for an average of 28 months.
“The fine needle aspiration detected tumour cells in the lymph node of half of the patients who were later shown to have node-positive disease through the surgical sentinel node biopsy procedure. In nearly all the cases that it missed, the tumour deposit in the sentinel node was very small and those patients seem to have an excellent prognosis – their survival seems similar to that seen in patients with no spread to the lymph nodes,” said the study's leader, Dr Christiane Voit, a dermatologist and head of the diagnostic unit at the Skin Cancer Center at Charité – Universitätsmedizin Berlin, the Medical University of Berlin, Germany. “This study shows that the technique is highly accurate and we are recommending that it should now be performed routinely before automatically performing sentinel lymph node biopsies, as a way to reduce the need for unnecessary sentinel node operations.”
Whether cancer has spread to the lymph nodes is the most important factor influencing the prognosis and treatment plan for patients with melanoma. Lymph node surgery for tumour staging has become more refined and less debilitating over the last decade. Traditional operations involve the removal of all lymph tissue from the area that drains the site of the tumour, but in some cancers, including melanoma, doctors now more often cut out only one or two key nodes, called sentinel nodes. If the sentinel node is free of cancer, patients don't need to have more extensive lymph node removal.