62: Validation of Invasive Area for Predicting Sentinel Node Status and Survival in Melanoma

Friday, March 24, 2023

11:14 AM – 11:24 AM

Location: Veterans Memorial Auditorium

Abstract Presenter(s)

Sophie E. Orme, MChem MBBS (she/her/hers)

Academic Foundation Doctor
Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK, England, United Kingdom

Disclosure(s): No financial relationships to disclose

First Author(s)

Sophie E. Orme, MChem MBBS (she/her/hers)

Academic Foundation Doctor
Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK, England, United Kingdom

Disclosure(s): No financial relationships to disclose

Author(s)

MB

Mark Bamford, FRCPath

Consultant Histopathologist
University Hospitals of Leicester NHS Trust, Leicester, UK, United States

Disclosure information not submitted.
MO

Marie O’Riordan, FRCPath

Consultant Histopathologist
University Hospitals of Leicester NHS Trust, Leicester, UK, United States

Disclosure information not submitted.
PD

Philip D. Da Forno, MD FRCPath

Consultant Histopathologist
University Hospitals of Leicester NHS Trust, Leicester, UK, United States

Disclosure information not submitted.
AS

Andrew Snelling, FRCS(Plast.)

Consultant Plastic & Reconstructive Surgeon
Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK
Norwich, England, United Kingdom

Disclosure information not submitted.
MH

Martin Heaton, MD FRCS(Plast.)

Consultant Plastic & Reconstructive Surgeon
Norfolk & Norwich University Hospital Foundation NHS Trust
Norwich, Norfolk, England, United Kingdom

Disclosure information not submitted.
RS

Rachael Stanley, PhD

Biorepository Manager
Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK, United States

Disclosure information not submitted.
RB

Roxanne Brunton-Sim, n/a

Research Consent Lead
Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK, United States

Disclosure information not submitted.
Marc D. Moncrieff, MD FRCS(Plast.)

Professor of Plastic and Reconstructive Surgery
Norfolk & Norwich University Hospital
Norwich, United Kingdom

Disclosure(s): No financial relationships to disclose
GS

Gerald Saldanha, PhD FRCPath

Consultant Histopathologist
University Hospitals of Leicester NHS Trust, Leicester, UK, United States

Disclosure information not submitted.

Disclosure(s):

Sophie E. Orme, MChem MBBS: No financial relationships to disclose

Marc D. Moncrieff, MD FRCS(Plast.): No financial relationships to disclose

Introduction: With the advent of adjuvant systemic therapy for micrometastatic stage III melanoma, there has been a recent renewed interest in identifying novel primary tumour biomarkers for predicting sentinel node (SN) status and survival outcome. We aimed to independently validate the previously-described calculated tumor area (CTA), measured as the calculated percentage of dermis occupied by invasive melanoma in a primary tumor.

Methods: 177 primary melanomas were assessed for standard histological characteristics, in addition to maximum primary tumor width and CTA. Multivariate analysis was undertaken to assess the performance of CTA as an independent predictor of both SN status and survival outcomes.

Results: The SN positive rate was 19.2% (34/177). Mitotic rate, ulceration status, lymphovascular invasion, age and primary tumor AJCC stage were all associated with SN status. The median CTA for SN negative patients was 3.2mm2 [IQR:1.2-10.9] compared to 6.7mm2 [IQR:4.2-26.9] for SN positive patients (p < 0.01). Multivariate analysis identified CTA, mitotic rate and age as independent predictors of SN status. There was significant correlation between Breslow thickness and dermal width of the primary tumor (R2=0.527; p< 0.001)

Maximum threshold analysis identified an optimal cutpoint of 6.3mm2 for disease-specific survival (DSS) (HR=1.01 (1.00-1.02); p=0.008), distant metastasis-free survival (HR=1.01 (1.00-1.02); p=0.005) and disease-free survival (HR=1.01 (1.00-1.02); p=0.005). The 5-year DSS for low-risk CTA tumors was 91.2% versus that of 61.3% for high-risk tumors (Figure 1). The two primary tumor characteristics shown by Cox regression to be independent predictors of DSS were ulceration status and CTA (HR=3.5 (1.21-10.81); p=0.021).

Furthermore we simplified CTA measurement, by transforming maximum tumor width with Breslow thickness as follows: (ln(width) + ln (Breslow)). Remarkably similar results were seen as before in terms of SN status and survival outcomes.

Conclusions: Our data shows that CTA is a better predictor of sentinel node status and survival outcome for primary melanoma compared to Breslow thickness. It is a simple measurement to obtain and could potentially lend itself to automation to increase objectivity.
Learning Objectives:
Understand the importance of accurate prognostic biomarkers and their role in risk stratification in the context of emergent therapies for micrometastatic melanoma
Define Calculated Tumor Area
Critically appraise Calculated Tumor Area as a predictor of sentinel lymph node status and survival outcome in comparison to standard histological characteristics including Breslow thickness