1120P - Development and external validation of a clinical prediction model to predict recurrence-free survival and melanoma-specific survival in patients with melanoma after sentinel lymph node biopsy

Background

The introduction of adjuvant systemic treatment for patients with high-risk melanoma has increased the importance of adequate melanoma staging. However, inconsistencies in outcomes between disease stages exist, as an increase in stage does not necessarily correspond to improved recurrence-free survival (RFS) or melanoma-specific survival (MSS). Therefore, there is a need for a tool that can predict patient-specific outcomes rather than grouping patients according to outcome.

Methods

A total of 4071 patients who underwent sentinel lymph node biopsy between 1997 and 2013 in four European melanoma centers were included in the development cohort. A prognostic model and nomogram were developed to predict recurrence and melanoma-specific mortality (MSM) on a continuous scale in patients with >pT1a melanomas. From this model, individual values for RFS and MSS were derived. For the purpose of external validation, a cohort consisting of 4822 patients was provided by the Melanoma Institute of Australia. Model performance was assessed by discrimination (C-index) and calibration.

Results

The prediction model for recurrence and MSM contained six prognostic factors: positive sentinel node (SN) status, Breslow depth, ulceration, age, location and SN tumor burden. The C-index for the recurrence model was 0.76, and was 0.79 for the MSM model. External validation showed good calibration for both outcomes with a C-index of 0.74 for recurrence and 0.76 for MSM.

Conclusions

This EORTC-MIA prediction model and nomogram provides patient-specific risk probabilities for recurrence and MSM and consequently RFS and MSS using only readily-available variables. The nomogram can support clinical decision-making for adjuvant treatment in patients with high-risk melanomas.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

A.A.M. Van der Veldt: Financial Interests, Institutional, Speaker, Consultant, Advisor: BMS, MSD, Merck, Roche, Novartis, Pfizer, Sanofi, Pierre Fabre, Ipsen, Eisai. J. Thompson: Financial Interests, Institutional, Advisory Board: BMS, MSD, GSK, Provectus; Financial Interests, Institutional, Other, travel & conference support: GSK, Provectus, Novartis. P. Rutkowski: Financial Interests, Personal, Invited Speaker, honoraria for lectures: MSD, BMS, Pierre Fabre; Financial Interests, Personal, Advisory Board: MSD, BMS, Pierre Fabre, Merck, Sanofi, Blueprint Medicines, Philogen; Financial Interests, Personal, Invited Speaker: Merck, Sanofi, Novartis, AstraZeneca; Financial Interests, Institutional, Research Grant, research grant for ISS: Pfizer; Financial Interests, Institutional, Funding, research grant for institution: BMS; Non-Financial Interests, Member of Board of Directors: Polish Society of Surgical Oncology; Non-Financial Interests, Member of Board of Directors, President: Polish Oncological Society. A.C.J. van Akkooi: Financial Interests, Institutional, Advisory Board: Amgen, Bristol Myers Squibb, Novartis, MSD - Merck, Merck-Pfizer, Pierre Fabre, Sanofi, Sirius Medical, 4SC, Provectus; Financial Interests, Institutional, Research Grant, NIVEC study: Amgen; Financial Interests, Institutional, Research Grant: Merck-Pfizer. All other authors have declared no conflicts of interest.