A new study suggests that in young patients with thin melanomas (0.5 -1mm depth) there may be an approximately 5% risk of lymph nodes being involved. As such, even though present guidelines do not recommend it, in young patients with melanomas between 0.5 and 1mm sentinel node biopsy may be considered.

Association Between Patient Age and Lymph Node Positivity in Thin Melanoma

Andrew J. Sinnamon, MD1; Madalyn G. Neuwirth, MD1; Pratyusha Yalamanchi, BA1; et alPhyllis Gimotty, PhD
JAMA Dermatol. Published online July 19, 2017. doi:10.1001/jamadermatol.2017.2497

Link to abstract:
http://jamanetwork.com/journals/jamadermatology/article-abstract/2643739