A new large retrospective international study involving more than 4,000 patients aimed to develop a novel model to predict recurrence-free survival and melanoma-specific survival after sentinel lymph node biopsy in patients with melanoma. Recently published in The Lancet Oncology, the results showed that the prediction model accurately predicted patient-specific risk probabilities for 5-year recurrence-free and melanoma-specific survival.1
The introduction of adjuvant systemic treatment for patients with high-risk melanomas necessitates accurate staging of the disease. Yet, inconsistencies in outcomes persist across disease stages as defined by the American Joint Committee on Cancer (8th edition). Here, the authors aimed to develop a predictive tool for patient-specific outcomes following sentinel lymph node biopsy in melanoma.1
Methods
This international, multicentre, retrospective study included patients >13 years of age with confirmed primary melanoma who underwent sentinel lymph node biopsy (SLNB) between October 29th, 1997, and November 11th, 2013, at four European melanoma centres (Berlin, Germany; Amsterdam and Rotterdam, the Netherlands; and Warsaw, Poland). Potential predictors of recurrence-free and melanoma-specific survival assessed were sex, age, presence of ulceration, primary tumour location, histological subtype, Breslow thickness, sentinel node status, number of sentinel nodes removed, maximum diameter of the largest sentinel node metastasis, and Dewar classification. A prognostic model and nomogram were developed to predict five-year recurrence-free survival on a continuous scale in patients with stage pT1b or higher melanomas. This model was also calibrated to predict melanoma-specific survival. Model performance was assessed by discrimination (area under the time-dependent receiver operating characteristics curve [AUC]) and calibration. External validation was done in a cohort of patients with primary melanomas who underwent SLNB between January 30th, 1997, and December 12th, 2013, at the Melanoma Institute Australia (Sydney, Australia).
Findings
The development cohort included 4,071 patients, with 889 having sentinel node-positive disease and 3,182 having sentinel node-negative disease. The validation cohort comprised 4,822 patients, including 891 with sentinel node-positive disease and 3,931 with sentinel node-negative disease. Median follow-up was 4.8 years in the development cohort and five years in the validation cohort. At the 5-year mark, recurrence-free survival rates were reported at 73.5% and 66.1% in the development and validation cohort, respectively, while 5-year melanoma-specific survival rates stood at 86.5% and 83.3%. The final model contained six prognostic factors: sentinel node status, Breslow thickness, presence of ulceration, age at SLNB, primary tumour location, and maximum diameter of the largest sentinel node metastasis. In the development cohort, for the model’s prediction of recurrence-free survival, the AUC was 0.80 (95%CI: 0.78-0.81); for the prediction of melanoma-specific survival, the AUC was 0.81 (0.79-0.84). External validation showed good calibration for both outcomes, with AUCs of 0.73 (0.71-0.75) and 0.76 (0.74-0.78), respectively.
Conclusions
The prediction model and nomogram accurately predicted patient-specific risk probabilities for 5-year recurrence-free and melanoma-specific survival. These tools could have important implications for clinical decision-making when considering adjuvant treatments in patients with high-risk melanomas.1
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