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Value of sentinel node status as a prognostic factor in melanoma: prospective observational study

BMJ 2006; 332 doi: (Published 15 June 2006) Cite this as: BMJ 2006;332:1423

Author's response

We thank Dr MacCabe for his comments on our paper. The Kaplan Meier
plots in this are based on melanoma free survival and therefore include
both deaths from and also recurrences of melanoma. Deaths from other
causes are censored. Dr MacCabe will see that in table 1 in the groups in
which he has an interest, patients with a primary melanoma 1-1.99mm thick
and a negative sentinel node biopsy, there are 6 events during the period
of observation, 2 deaths from melanoma and 4 recurrences. In fact only 5
of these are included in the Kaplan Meier curve as the exact date of one
of the recurrences was not established. Thus these curves do give a
reasonable assessment of melanoma free survival.

Dr MacCabe's calculations in paragraph 3 of his letter fail to take
account of the fact that our mean follow-up time, when the paper was
written, was 42 months as stated in the text. These patients are not
discharged at 6 years and very few have been lost to follow-up.

Competing interests:
None declared

Competing interests: No competing interests

27 June 2006
Rona M Mackie
Senior Research Fellow
University of Glasgow G12 8RZ