Reader TTS

Access through your institution Buy or subscribe ARISING FROM: Thomas MJ (2008) Prognostic false-positivity of the sentinel node in melanoma. _Nat Clin Pract Oncol_ 5: 18–23

[doi:10.1038/ncponc1014] We would like to take the opportunity to comment on the Review article by Thomas.1 Thomas has calculated that the incidence of false positivity in the sentinel lymph

node (SLN) group reported by Morton _ et al_.2 is 24%. Using a different calculation method we have produced an alternative interpretation of the MSLT-1 subgroup analysis results. The

randomized design of MSLT-1 trial and its large sample size allow us to estimate the number of patients in the observation arm who were sentinel node positive at the time of randomization,

and who subsequently died from melanoma. We have used these estimates to calculate a theoretical risk ratio that compares the survival of patients with positive sentinel nodes in the biopsy

and observation groups. The steps are as follows: * 16% of the biopsy group (764 patients) were SLN positive2 * Therefore, we would expect 16% of 500 patients of the observation group to

have been SLN-positive, i.e. 80 patients * Of the SLN-negative patients in the biopsy group, 62 (9.7%) died from melanoma2 * Therefore, we would expect 9.7% of the SLN-negative patients in

the observation group to have died from melanoma, i.e. 40 of 420 patients * In the whole observation group, 69 died from melanoma,2 which means that 29 (i.e. 69–40) who died were patients

who would have been SLN-positive at randomization * Thus, we estimate that for the observation group, 29 of 80 (36%) SLN-positive patients died from melanoma * In the biopsy group, 32 of 122

(26.2%) SLN-positive patients died from melanoma2 * Thus, the crude theoretical risk ratio is (32/122)/(29/80) = 0.72 * The crude risk ratio from the comparison made by Morton and

coauthors2 is (32/122)/(38/78) = 0.54 * The hazard ratio reported2 was 0.51, which is very close to the crude relative risk of 0.54 that we calculated This is a preview of subscription

content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 12 print issues and online access $209.00 per year only $17.42 per issue

Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL

ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support REFERENCES * Thomas JM (2008) Prognostic false-positivity of the sentinel node

in melanoma. _Nat ClinPract Oncol_ 5: 18–23 Article  Google Scholar  * Morton DL _ et al_. (2006) Sentinel-node biopsy or nodal observation in melanoma. _N Engl J Med_ 355: 1307–1317 Article

  CAS  Google Scholar  * Morton DL _ et al_. (2007) Authors' reply to a letter to the editor re: Sentinel-Node Biopsy in Melanoma. _N Engl J Med_ 356: 418–419; author reply 419–421

Article  Google Scholar  Download references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Cutaneous Pathology, 26 Leura Street, Nedlands, 6009, Western Australia Peter J Heenan, Dallas R

English & Minh H Lam Authors * Peter J Heenan View author publications You can also search for this author inPubMed Google Scholar * Dallas R English View author publications You can

also search for this author inPubMed Google Scholar * Minh H Lam View author publications You can also search for this author inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to

Peter J Heenan. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS

ARTICLE Heenan, P., English, D. & Lam, M. Prognostic false-positivity of the sentinel node in melanoma. _Nat Rev Clin Oncol_ 5, E1 (2008). https://doi.org/10.1038/ncponc1190 Download

citation * Issue Date: July 2008 * DOI: https://doi.org/10.1038/ncponc1190 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link

Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative