BILLCD8 - A Multivariable Survival Model as a Simple and Clinically Useful Prognostic Tool to Identify High-risk Cutaneous Melanoma Patients

Abstract

Aim: To develop a multivariable survival model based on histopathological parameters that would provide the best possible estimate of the risk of death in cutaneous melanoma patients.

Materials and methods: Breslow thickness and Infiltrating Lymphocytes (BILL(CD8)) is based on two key parameters, namely Breslow thickness and tumor-infiltrating lymphocytes (TILs) shown to be the most important prognostic factors using logistic regression model. The next step was to apply a decision tree method to analyze the impact of the percentage of CD8+ lymphocytes on the risk of cancer death.

Results: A patient is given two points if Breslow thickness is >2 mm and one point if TILs are not found in the tumor. The probability of death over a 4-year follow-up is 75% if the patient's score is 3 points; in patients with 0 point score the risk of death is 0%. A significant positive impact of high percentage of CD8+ lymphocytes on the risk of death was shown in the subgroup of melanoma patients with Breslow thickness >2 mm where the risk of death is only 28%. In the case of low percentage of CD8+ lymphocytes in melanomas with Breslow thickness over 2 mm, the risk is as high as 67%.

Conclusion: Breslow thickness and TILs, with the evaluation of the CD8+ lymphocytes, may be used for precise prognostic stratification of patients and may help intensify the follow-up, diagnose a relapse sooner and apply proper treatment.

Keywords: Prognosis; histopathology; malignant melanoma; survival model.