There has been longstanding uncertainty surrounding the optimal surveillance strategies for people with melanoma after completion of treatment. In 2015, NICE recommended that imaging only be considered in stage III disease and higher (or stage IIC disease if the person has not had a sentinel lymph node biopsy [SLNB]). However, the exact role imaging should play in these stages was unclear, particularly for people with high-risk stage II disease (IIB-C) for which evidence shows poor long-term survival. NICE also recommended a stage-stratified follow-up for clinic visits for stages I-III. However, these recommendations were made on very little evidence and needed to be re-evaluated following the introduction of adjuvant therapies to the treatment of stage III disease and recent changes to how melanoma is staged in the AJCC 8 edition. There was little guidance for the follow-up of stage IV (and unresectable stage III) disease. The role of ultrasound during follow-up also needed clarifying. Ultrasound is better than alternative modalities at detecting lymph node recurrence but there has been uncertainty as to whether its use leads to improved outcomes such as mortality and distant disease progression. The 2015 update also recommended that the brain be included as part of imaging for the staging of people with suspected stage IV melanoma and to consider imaging the brain as part of follow-up for all people with melanoma. These recommended were made on very limited evidence and needed to be updated to consider whether a wider range of people (particularly people with stage III melanoma) deemed to be at sufficiently high risk for brain metastases (BM) would benefit from a brain scan. Additionally, clinical practice would benefit from more prescriptive recommendations around how and when imaging of the brain should be conducted during follow-up. Finally, the diagnostic accuracy of different brain imaging modalities for detecting brain metastases is unclear. NICE recommended the use of CT for brain imaging in adults and MRI in children. MRI is thought to be more accurate but is also more costly. Review questions 6.1 and 6.4 attempted to establish whether different follow-up strategies (less intensive compared to more intensive) identify more recurrences, identify recurrences earlier/later or impact differentially on quality of life. It also looked at the risk of recurrence over time for difference stages and how this is affected by the presence of risk factors (such as ulceration and a high mitotic rate). This review question focused on the follow-up of stages I-III following surgery and/or conclusion of treatment. Review question 6.2 assessed the diagnostic accuracy of imaging strategies for detecting recurrence or spreading of melanoma in stage IIB-III melanoma in the following scenarios: during surveillance in asymptomatic patients; in those people suspected of recurrence; for re-staging after completing treatment/surgery. Review question 6.3 assessed the diagnostic accuracy of different imaging modalities in detecting brain metastases. Additionally, it aimed to identify those people at greater risk of brain metastases, who would therefore benefit most from additional investigations of the brain. Review question 6.4 focused on stage IV (and unresectable III) disease and incorporated all elements covered in questions 6.1 and 6.2. For the purposes of this review, questions 6.1 and 6.4 were combined into a single search looking at risk factors and patterns of recurrence and/or survival across all stages of melanoma. Review question 6.2 focused specifically on diagnostic accuracy of different imaging modalities and strategies during follow-up and 6.3 looked specifically at the development of brain metastases (and included analyses of both risk factors and diagnostic accuracy for detecting brain metastases). See the PICO below for further information.