External validation of a prognostic model to predict survival of patients with sentinel node-negative melanoma
Menée à partir de données portant sur 4 235 patients atteints d'un mélanome cutané sans envahissement du ganglion sentinelle (durée médiane de suivi : 50 mois), cette étude évalue la performance du modèle de l"European Organisation for Research and Treatment of Cancer", basé sur l'épaisseur de Breslow, la présence d'une ulcération et le site de la tumeur primitive, pour prédire la survie des patients
Background : Identifying patients with sentinel node-negative melanoma at high risk of recurrence or death is important. The European Organisation for Research and Treatment of Cancer (EORTC) recently developed a prognostic model including Breslow thickness, ulceration and site of the primary tumour. The aims of the present study were to validate this prognostic model externally and to assess whether it could be improved by adding other prognostic factors.
Methods : Patients with sentinel node-negative cutaneous melanoma were included in this retrospective single-institution study. The
β values of the EORTC prognostic model were used to predict recurrence
‐free survival and melanoma-specific survival. The predictive performance was assessed by discrimination (c-index) and calibration. Seeking to improve the performance of the model, additional variables were added to a Cox proportional hazards model.
Results : Some 4 235 patients with sentinel node-negative cutaneous melanoma were included. The median follow-up time was 50 (i.q.r. 18·5–81·5) months. Recurrences and deaths from melanoma numbered 793 (18·7 per cent) and 456 (10·8 per cent) respectively. Validation of the EORTC model showed good calibration for both outcomes, and a c-index of 0·69. The c-index was only marginally improved to 0·71 when other significant prognostic factors (sex, age, tumour type, mitotic rate) were added.
Conclusion : This study validated the EORTC prognostic model for recurrence-free and melanoma-specific survival of patients with negative sentinel nodes. The addition of other prognostic factors only improved the model marginally. The validated EORTC model could be used for personalizing follow-up and selecting high-risk patients for trials of adjuvant systemic therapy.
British Journal of Surgery , article en libre accès, 2019