Chowdhury et al — Truncal Melanoma Contralateral SLN Drainage Prevalence

Retrospective review, The Christie NHS Foundation Trust, Manchester, UK, Oct 2006–Nov 2024.

Correction — see Fact-Check Log

Original note said “1300 patients… 1.1%… most relevant location was at the back, 21%.” Corrected below.

Verified findings

  • 1308 consecutive patients (not 1300) underwent WLE + SLNB for truncal melanoma
  • Contralateral drainage occurred in 14 patients (1.1%)
  • Location of primary scar in the 14: left lower back 4 (28.6%), right upper back 4 (28.6%), right lower back 2 (14.3%), right upper abdomen 2 (14.3%), left lower abdomen 1 (7.1%), right upper chest 1 (7.1%) → 10/14 (71%) posterior torso, of which 6/14 (43%) specifically lower back
  • 3 patients (21.4%) experienced melanoma recurrence during follow-up — this is the recurrence rate, not a location statistic
  • Authors hypothesise congenital lymphatic variation as a contributing factor

My take

This is our closest epidemiological comparator — same drainage direction question (truncal melanoma → contralateral axilla) as our case. Use the corrected numbers above directly in the Introduction/Discussion.