The studies in this thesis aimed to provide insight in the real-world treatment patterns and outcomes of advanced melanoma patients in the Netherlands, to investigate the outcomes of BRAF V600-mutant and wild-type patients, to describe advanced melanoma care during the COVID-19 pandemic, and to assess and describe the added value of quality registries. Chapter 2. Real-world outcomes of first-line ipilimumab plus nivolumab Ipilimumab plus nivolumab is the most recent major addition of systemic therapies for the treatment of advanced melanoma. We observed that real-world patients receiving first-line ipilimumab plus nivolumab can achieve long-term survival, including patients with characteristics that were not represented in the clinical trial. Chapter 3. Hospital variation survival outcomes of advanced melanoma patients In 2014-2015, there was significant hospital variation in 2-year survival outcomes, even after correcting for case-mix and treatment with new systemic therapies. This significant variation may be caused by differences in uptake of new systemic therapies. From 2016 onwards, no significant differences in 2-year overall survival (OS) probabilities existed. Chapter 4. Population mortality in advanced melanoma patients In this chapter we investigate the relative contribution of population mortality in each response state for different age groups. Population mortality only played a large role for older patients alive at 1 year after diagnosis with a partial response (PR) or CR. Even though survival outcomes of advanced melanoma patients have improved over the last decade, the vast majority of patients still die due to melanoma-related mortality. Chapter 5. Outcomes of advanced melanoma according to BRAF V600 status Anti-PD-1 antibodies and BRAF/MEK inhibitors are the two main groups of systemic therapy in the treatment of BRAF V600-mutant advanced melanoma. Patients with BRAF V600-mutant disease are able to receive both systemic therapies while patients with BRAF V600 wild-type disease can only use ...