Sentinel node biopsy to check for systemic spread of malignant melanoma is cheap but is it really effective?
A recent editorial in the BMJ suggests not.
According to surgeon J.M. Thomas and research fellow E.J. Patocskai, Royal Marsden Hospital, London, the benefits of this popular procedure are assumed rather than proven.
There is some evidence that a negative result can indicate that a patient has an 88.5 per cent chance of being disease free three years after the procedure. However, there is no evidence that a negative biopsy correlates with long term survival. While the procedure is often used to select patients for 'therapy', there currently is no effective therapy to prolong survival in cases where the cancer has spread.
Sentinel needle biopsy is also often used to select patients who will then go on to have the more invasive and more expensive procedure of node dissection. So, argue Thomas and Patocskai, where is the real benefit?
Complications of the procedure include seroma (a tumour like collection of blood in the tissues), wound infection, allergic reactions and, more disturbing, spread of the cancer. In addition, the false negative rate can vary from 0 to 25 per cent.
Sentinal node biopsy is used widely in the US and Australia. However, in the UK, doctors are more cautious, using observation and the more extreme procedure of therapeutic lymph node dissection only for patients who develop metastasis (BMJ, 2000; 321: 3-4).