Ultrasound predicts metastases, survival of patients with melanoma

Researchers in Germany and the Netherlands have discovered ultrasound-based patterns that can accurately diagnose the presence and stage of metastases in patients with melanoma. Sonography, they say, could replace surgical biopsies and predict patient survival.

The technique has the potential to spare patients unnecessary invasive procedures if combined with ultrasound-guided fine-needle biopsy of lymph nodes, said principal investigator Dr. Christiane Voit, chief of the Skin Cancer Center's diagnostic unit at the Charité Medical University of Berlin.

"For the first time we have established that ultrasound patterns can be used as criteria for diagnosing disease progression and tumor burden," Voit said.

The study is the product of an eight-year-long collaboration between Charité, the Daniel den Hoed Cancer Center at Erasmus University in Rotterdam, and the Department of Medical Oncology at the Armed Forces Hospital in Ulm, Germany. Voit and colleagues have thus far prospectively enrolled 850 melanoma patients. Of these, 400 have already undergone sonography, conventional sentinel node surgical biopsy as the reference standard test, and an average of nearly four years of follow-up. Patients with suspicious sonography findings also underwent ultrasound-guided fine-needle biopsy.

The investigators tested several different ultrasound patterns and found that two of them, peripheral perfusion and balloon-shaped lymph nodes, provided consistent signs, respectively, of early- and late-stage metastatic disease. Researchers also found these signs could accurately identify the tumor burden before surgical biopsy in up to 90% of cases.

Voit released findings Sept. 23 at the 2009 European Cancer Organization meeting, held jointly with the European Society for Medical Oncology meeting.

The balloon-shaped ultrasound pattern, with or without central echoes, indicated a large number of cancer cells in the sentinel node in more than 80% of cases, Voit said. The pattern appeared exclusively in cases of advanced metastasis. Peripheral perfusion, on the other hand, suggested an early sign of lymph node architecture disruption by angiogenesis, she said.

These two ultrasound patterns could predict overall survival, according to researchers. Based on their findings, they estimated five-year survival rates of more than 90% for patients with neither pattern. Five-year survival rates for patients with peripheral perfusion and balloon-shaped patterns were 87% and 56%, respectively.

Surgical biopsy of the sentinel nodes remains the standard of care in cases of suspected metastatic spread from melanoma, but the practice is controversial. The invasive procedure could be unnecessary for about 80% of patients, who have to endure side effects such as chronic inflammation and seroma, according to the researchers.

"Using ultrasound first to detect the presence-or not-of sentinel node metastases could be a noninvasive way of limiting the numbers of patients who require subsequent surgery or simply watchful follow-up care," the investigators said.