Appropriate surveillance of patients with melanoma treated with curative intent is vital to improve patient outcomes. A systematic review was conducted to capture locoregional recurrence and metastatic disease, and to evaluate the effectiveness of various surveillance strategies. MEDLINE, EMBASE, PubMed, Cochrane Database of Systematic Reviews, and National Cancer Institute Clinical Trials Database were searched. Randomized controlled trials (RCTs) and comparative studies reporting at least one patient-related outcome were included. Exclusion criteria included: published in non-English or recruited >20 % or an uncertain percentage of non-target patients without conducting a subgroup analysis for the target patients. This review was registered at PROSPERO (CRD42021246482). Among 17,978 publications from the literature search, one RCT and five non-randomized comparative studies were included and comprised 4016 patients. The aggregate evidence certainty was low for the RCT and very low for the comparative studies, as assessed by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. For patients with stage IA-IIC melanoma, a reduced follow-up schedule with clinical follow-up strategies alone may be safe and cost-effective. For stage IIC-IIIC patients, at least two serial PET/CT or whole-body CT and brain MRI imaging within a median follow-up of 31.2 months may detect 50 % of recurrences that lead to additional management, such as surgery. PET/CT may have a higher positive predictive value and lower false positive rate compared with CT alone in detecting recurrence in stage I-III patients. Surveillance protocols should be based on individual risk of recurrence and established best practices when formulating follow-up strategies, as suggested by the studies reviewed. Future high-quality studies are needed to clarify the frequency of imaging follow-up strategies, especially in patients with high-risk stage II melanoma.

Background/Objectives: Merkel cell carcinoma (MCC) is an uncommon but aggressive skin malignancy with a rising incidence. Limited data exist on the survival of MCC patients in Canada. This study analyzes the survival of patients diagnosed with MCC in Canada between 2000 and 2018 compared to those reported by the American Joint Committee on Cancer (AJCC) 8th edition. Risk factors included in the database were sex, age, and immunosuppression. Methods: We conducted a multicenter retrospective cohort study including patients diagnosed with stage I–IV MCC aged ≥18 from 10 Canadian university centers and three provinces. We evaluated differences in survival compared to the cohort included in the AJCC 8th edition. Results: Among 899 patients diagnosed with MCC in Canada, 327 (36.4%) had stage I, 195 (21.7%) had stage II, 305 (33.9%) had stage III, and 72 (8.0%) had stage IV at presentation. When examining risk factors, 61.1% (549) were male, 10.2% (92) were immunosuppressed, and age at diagnosis was 75 years (±11). The five-year overall survival for patients diagnosed in Canada at stage I was 56.8%, stage IIA 54.0%, stage IIB 28.0%, stage IIIA 52.7%, stage IIIB 40.2%, and stage IV 13.9%. Conclusions: Survival from MCC is low in Canada across all stages. Compared to the AJCC 8th edition, patients diagnosed with MCC in Canada have similar survival rates, except for patients diagnosed with stage IIIB, who have lower survival rates in the AJCC 8th edition. Further research is needed to improve the survival of this rare malignancy.