Representation of melanoma depth staging with limited central section sampling

BACKGROUND AND OBJECTIVESFor thick melanomas, retaining the primary lesion during neoadjuvant therapy may enhance immune response through increased antigen load. This study assessed whether a central section from serially processed melanoma specimen, representing a transectional incisional biopsy, accurately reflects Breslow thickness and ulceration compared to full serial sectioning.

PATIENTS AND METHODSFrom a single center, histological slides of 78 invasive melanomas from 76 patients were retrospectively collected. Specimen were digitized, tumor-thickness and ulceration were measured across all tissue sections. The most central section was compared to the overall specimen.

RESULTSAcross 78 paired comparisons, the median difference between central and maximum depth measurement was below 0.2 mm (0 mm, IQR 0.02, p < 0.001), with 64 (82.1%) cases ≤ 0.2 mm. Ulceration was present in 9 cases (11.5%), always detectable in the central section. T-stage remained unchanged in 73/78 cases (93.6%), the remaining 5 cases showed higher stages with full workup within T-stages ≤ 2.

CONCLUSIONSIn this retrospective cohort, a central section provided Breslow thickness and T-stage equivalent to full serial sectioning in most cases, underestimation occurred only in thin melanomas. These findings provide a pre-clinical foundation for trials testing whether retaining the primary melanoma during neoadjuvant therapy may enhance treatment efficacy.

Abstract from PubMed