e22094 Background: The success of adjuvant therapy for patients with AJCC stage III melanomas coupled with the increased risk of mortality for patients with AJCC stage IIB compared to IIIA tumours has paved the way to adjuvant immunotherapy trials for patients with sentinel lymph node (SLNB) –ve AJCC stage II disease. However, the lack of biomarkers able to appropriately stratify high-risk tumour subsets limits patient recruitment. We have recently identified the combined immunohistochemical (IHC) expression of AMBRA1 and Loricrin (AMBLor) in the epidermis overlying non-ulcerated AJCC stage I melanomas as a robust prognostic biomarker and valuable pre SLNB test. Methods: Retrospective analysis of AMBLor was performed in three geographically distinct cohorts of AJCC stage II melanomas using a clinically validated automated IHC assay and semi quantitative binary scoring analysis to define high vs low risk subgroups. Results: Data revealed loss of AMBLor overlying non-ulcerated high risk AJCC stage IIA or B tumours correlated with a significant reduction in disease free survival (DFS) at 12 years to 55% compared to 89% for patients with AMBLor low risk tumours (P = 0.015; HR 4.83, 95% CI: 2.29-10.14). Sub-cohort multivariate analysis of 80 non ulcerated stage IIB tumours also revealed reduced DFS at 12 years to 68% in AMBLor high-risk compared to 83% in AMBLor low-risk tumour subsets, with an assay sensitivity of 97% and a negative predictive value of 90%. Furthermore, sub-cohort analysis of SLNB –ve AJCC stage IIA or B tumours additionally identified 5 genuinely low risk cases in which DFS at 10 years was 100% compared to only 36% in 37 patients in which AMBLor was lost. Conclusions: Collectively these data indicate AMBLor as a novel prognostic biomarker for patients with non-ulcerated AJCC stage II melanomas as well as companion/stratifying biomarker for adjuvant immunotherapy, the use of which will increase clinician confidence for patient recruitment as well as reduce patient morbidity.
Utilization and Survival Benefit of Adjuvant Immunotherapy in Resected High-Risk Stage II Melanoma