Age, anatomical location-related factors dictate biopsy considerations for T1b melanomas

Key takeaways:

• T1b melanomas on the face, ear or scalp had a 31% increased risk of lymph node or distant metastasis.
• T1b melanomas on all other anatomic sites combined had a much lower risk of 3.6%.

Younger patients and those with T1b melanomas on the face, ear or scalp should undergo sentinel lymph node biopsies, according to a study.

“Critical to guiding recommendations for [sentinel lymph node biopsy (SLNB)] in T1b melanomas is understanding the incidence of lymph node metastasis,” Margaret Y. Huang, BS, a student at Keck School of Medicine at University of Southern California, Los Angeles, and colleagues wrote. “In this study, we aimed to investigate whether particular anatomic locations of T1b melanomas are associated with an increased risk of lymph node or distant metastasis. We also sought to examine age-related effects on lymph node or distant metastasis in T1b melanomas as well as all melanomas combined.”

Using data from two hospitals in Los Angeles County from January 2010 through January 2020, the retrospective study included 620 patients with primary melanomas, 566 of which were staged.

Of the 41 melanoma cases that were T1b, 13 were located on the face, ear or scalp. Results showed that T1b melanomas on the face, ear or scalp had an increased risk of lymph node or distant metastasis vs. T1b melanomas on all other anatomic sites combined (31% vs. 3.6%; P = .028).

For all melanomas diagnosed among patients aged 64 years and older, the risk of lymph node (OR = 0.26; 95% CI, 0.12-0.53) or distant metastasis (OR = 0.51; 95% CI, 0.27-0.94) combined decreased with age. In contrast, the risk of distant metastasis for T1b melanomas increased with age (OR = 1.26; 95% CI, 1.06-1.73). According to the authors, the small sample size limited the risk analysis of lymph node metastasis with T1b melanomas.

“Based on our study findings, T1b melanomas of the face, ear or scalp, with a higher risk of lymph node or distant metastasis, may warrant stronger consideration of SLNB as well as consideration of whole-body imaging and closer surveillance compared to T1b melanomas of other anatomic locations,” the authors wrote.

Additionally, the authors recommended that younger patients may be more strongly considered for SLNB, whereas older patients may be more strongly considered to have whole-body imaging.