Association of Sentinel Node Biopsy and Pathological Report Completeness with Survival Benefit for Cutaneous Melanoma and Factors Influencing Their Different Uses in European Populations.

Objectives: Standard care for cutaneous melanoma includes an accurate pathology report (PR) and sentinel lymph node biopsy (SLNB) for staging clinically node-negative >1 mm melanomas. We aimed to investigate the frequency of these indicators across European countries, also assessing consequences for survival. Methods: We analyzed 4245 melanoma cases diagnosed in six European countries in 2009-2013. Multivariable logistic regression was used to estimate the Odds Ratio (OR) of receiving complete PR with eight items or SLNB and model-based survival to estimate the five-year relative excess risks of death (RER). Results: Overall, 12% patients received a complete PR (range 2.3%, Estonia-20.1%, Italy); SLNB was performed for 68.8% of those with cN0cM0 stage (range 54.4%, Spain-81.7%, Portugal). The adjusted OR of receiving a complete PR was lower than the mean in Estonia (OR 0.11 (0.06-0.18)) and higher in Italy (OR 6.39 (4.90-8.34)) and Portugal (OR 1.39 (1.02-1.89)); it was higher for patients operated on in specialized than general hospitals (OR 1.42 (1.08-1.42)). In the multivariate models adjusted for age, sex, country and clinical-pathological characteristics, the RER resulted in being higher than the reference for patients not receiving a complete PR with eight items (RER 1.72 (1.08-2.72)), or for those not undergoing SLNB (RER 1.76 (1.26-2.47)) Patients with non-metastatic node-negative thickness >1 mm melanoma who did not undergo SLNB had a higher risk of death (RER (RER 1.69 (1.02-2.80)) than those who did. Conclusions: Accurate pathology profiling and SLNB carried survival benefit. Narrowing down between-countries differences in adhesion to guidelines might achieve better outcomes