Researchers have shown for the first time that patterns of ultrasound signals can be used to identify whether or not cancer has started to spread in melanoma patients, and to what extent. The discovery enables doctors to decide on how much surgery, if any, is required and to predict the patient's probable survival.
Dr Christiane Voit told Europe's largest cancer congress, ECCO 15 - ESMO 34 [1], in Berlin today (Wednesday 23 September): "We have identified two ultrasound patterns of lymph node metastasis in melanoma patients which can identify correctly any amount of tumour cells in the sentinel lymph nodes in 75-90% of cases before proceeding to surgery on the sentinel lymph nodes."
Dr Voit, who is a dermatologist and head of the diagnostic unit at the Skin Cancer Centre at Charit- - Universit-tsmedizin Berlin, the Medical University of Berlin, Germany, said that although her research needs to be confirmed in multi-centre, randomised clinical trials, it had the potential to spare patients unnecessary surgery, especially if it was combined with ultrasound-guided fine needle biopsy of lymph nodes rather than conventional surgery.
Since 2001 Dr Voit and her colleagues in Germany and The Netherlands have included 850 melanoma patients in a prospective study to investigate the use of ultrasound in diagnosis and treatment planning. They have already demonstrated that ultrasound-guided fine needle biopsy of sentinel nodes before conventional sentinel node surgery can identify up to 65% of patients in whom the cancer has started to spread. The study presented today shows how far ultrasound patterns correlate with disease progression, tumour burden, survival and prognosis in the first 400 of these patients with stage I/II melanoma and with the longest follow-up.
Before having sentinel node surgery the patients were investigated using ultrasound, and these results were checked against the results of the subsequent surgery. The researchers found that two ultrasound patterns together could correctly identify the amount of cancer cells in the lymph nodes in 80% of cases.
A balloon shape ultrasound pattern with or without loss of central echoes (where the lymph node has lost central echoes or still has some residual central echoes, but these are wandering toward the rim, giving an asymmetrical shape to the centre) was an indicator in up to 83% of cases of a large amount of cancer cells in the sentinel node. "This ultrasound pattern was a late sign, only occurring in cases of advanced metastasis," said Dr Voit.
A pattern of peripheral perfusion (where small blood vessels start to surround the lymph node) was an early sign of a small number of cancer cells present. "The early signs are signs of first disruption of the normal lymph node architecture by an early stage metastasis. The most important one is peripheral perfusion, which shows angiogenesis (the formation of new blood vessels) is occurring," she explained.