The need to expand global access to radiotherapy.

378 www.thelancet.com/oncology Vol 15 April 2014 tumour is malignant melanoma. Likewise, sentinel lymphadenectomy is not useful for staging disease in the management of atypical Spitz tumours because metastases from these tumours are not prognostic. The results of Lallas and colleagues’ study establish that sentinel lymph node metastasis is not of diagnostic or prognostic signifi cance in patients with atypical Spitz tumours. What has not been determined is the therapeutic usefulness, if any, of sentinel lymphadenectomy. This question is important because some investigators suggest that sentinel lymphadenectomy is an unnecessary test if there is no prognostic signifi cance. Additionally, some would argue against sentinel lymphadenectomy since no action will be taken if there is a positive sentinel lymph node (completion lymphadenectomy and adjuvant therapy are no longer recommended in patients with atypical Spitz tumour and sentinel lymph node metastases). Continued use of sentinel lymphadenectomy in the setting of atypical Spitz tumour is supported by the hypothesis that removal of any lymph node harbouring metastatic disease is therapeutic and prolongs the disease-free interval. There is not enough data to prove or disprove this hypothesis; however, in the current study, six of 541 patients died from complications of metastatic disease and only one of these patients had been treated with sentinel lymphadenectomy. However, no patient had disease progression in a recent report of children with atypical Spitz tumours who were not treated with sentinel lymphadenectomy. Overall the small number of patients and absence of 20 years of follow-up in these studies does not support a specifi c conclusion; the possibility that sentinel lymphadenectomy is of therapeutic benefi t in patients with atypical Spitz tumours remains. Interestingly, molecular staging of the primary tumour might have a role in atypical Spitz tumour. In a landmark study by Gerami and colleagues, a subset of patients with atypical Spitz tumours was identifi ed as having chromosomal copy number aberration and homozygous 9p21 deletions. In atypical Spitz tumours these specifi c molecular abnormalities in the primary cutaneous tumour correlate with progression beyond the sentinel lymph node. Although the presence of lymph node metastases is not a sign of poor prognosis in patients with atypical Spitz tumours, it is unknown whether removing these metastases is of therapeutic benefi t. Ultimately, this might be an arena where molecular analysis provides the best staging data.