Trend and socioeconomic disparities in survival outcome of metastatic melanoma after approval of immune checkpoint inhibitors: a population-based study.

backgroundThe approval of immune checkpoint inhibitors (ICI) for metastatic melanoma in 2011 has changed the treatment landscape of this disease. However, current trend of the population-based survival remains unclear.

methods8078 patients with metastatic melanoma diagnosed in the pre-ICI (2005-2010) and post-ICI period (2011-2016) were enrolled from the Surveillance, Epidemiology, and End Results (SEER) program for survival comparison. Propensity score matching (PSM) was performed to reduce selection bias. Cox proportional hazards model was applied for identifying survival-related factors and constructing a prognostic nomogram. The accuracy of the nomogram was determined by concordance index (C-index), calibration curves, and validated by an internal cohort.

resultsPatients in the post-ICI period had a significantly longer median overall survival (OS) than those in the pre-ICI period, even after performing PSM between the two periods. We also found socioeconomic disparities in the survival improvement. Significant differences in OS between the two periods were only observed in cases with medical insurance and patients living in urban or low-poverty area, but not uninsured cases and patients from rural or high-poverty area. For patients in the post-ICI period, multivariate analysis demonstrated that socioeconomic and insurance status were independent prognostic factors, which can be combined with other clinical variates into a nomogram for OS prediction with promising C-index of 0.672 and 0.650 in the training- and testing cohort, respectively.

conclusionAn overall trend to favorable survival at the population level and socioeconomic disparities in the survival trend are observed in metastatic melanoma after the ICI approval. The proposed nomogram is available for prognostication in the current melanoma management.