Editor—The arguments put forward by Thomas and Clark against the use of sentinel node biopsy in malignant melanoma have not changed over the past four years.1,2 However, data are now available to test the hypothesis that completion lymphadenectomy might increase the rate of in-transit disease.
We identified 10 studies, including our own, which report patterns of relapse separately according to sentinel node status.3 Overall we found 701 relapses among 4713 subjects, of which 94 were nodal, 201 were either in-transit or local recurrence, and 406 were distant, giving an absolute rate of 2%, 4.3%, and 8.8%, respectively. In cohorts not subjected to selective lymphadenectomy the equivalent figures are 7.8% nodal, 3.4% in-transit, and 4.4% distant.4 In other words, selective lymphadenectomy reduces the absolute rate of nodal relapse mainly at the expense of an increased rate of distant metastases. It is difficult to attach too much importance to the modest increase in the rate of in-transit disease as the cohorts subjected to selective lymphadenectomy commonly excluded patients with stage 1A disease, whereas the historical cohort was unselected.
As expected, the overall relapse rate among patients with a positive node was almost three times that of the cohorts negative node result (11.6% v 31%), but it is also instructive to compare patterns of relapse according to sentinel node status. Among sentinel node negative subjects, 16% of all relapses were nodal, 53% were distant, and 31% were in-transit. Among sentinel node positive cohorts 8% were nodal, 59% were distant, and 33% were in-transit. This small difference for in-transit disease is not significant and does not support the hypothesis that completion lymphadenectomy increases the likelihood of in-transit disease.
We also take issue with the statement that adjuvant treatment with interferon confers no survival benefit. The meta-analysis quoted by Thomas and Clark shows an unequivocal and dose related improvement for disease free survival (P < 0.0001) and, if the analysis is confined to the high dose studies, a marginal benefit for overall survival (P = 0.05).5 The fact that the NHS is not prepared to fund this treatment owes more to cost than toxicity.
Competing interests: None declared.
References
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