Simple SummaryThe risk of melanoma is higher in first-degree relatives (FDRs, i.e., brother, sister, father, mother, or children) of a patient with melanoma than in the general population. FDRs are advised to undergo annual screening to detect any melanoma earlier and to adopt sun-protective behavior by seeking shade, wearing a hat and long-sleeved clothing, staying indoors between 12 noon and 4 p.m., and applying sunscreen with SPF > 50. We know that these general instructions, usually given orally to the patients, are inconsistently followed by FDRs. Our goal was to determine whether written support intended for FDRs of patients would improve early detection and photoprotection as compared with usual oral advice. We developed and evaluated the use of a tip sheet given by patients to their FDRs. The adherence of FDRs to early detection by medical examination and to sun protection was not improved by delivery of the tip sheet as compared with the usual oral advice.Background: First-degree relatives (FDRs, defined as parents, children, and siblings) of melanoma patients are at a two-to-fivefold increased risk of developing melanoma themselves. FDRs are advised to perform self-skin examination (SSE) and annual medical total cutaneous examination (TCE) performed either by a dermatologist or a general practitioner, and to change their sun-related behavior. This advice is given orally to melanoma patients who are asked to relay the information to their FDRs. Objective: Our aim was to determine the impact of providing a tip sheet to melanoma patients intended to their first-degree relatives (FDRs) on early detection and sun-related behaviors in this group at increased risk of melanoma. Methods: A superiority, cluster-randomized trial was conducted at nine hospital centers. In the intervention group, dermatologists were asked to deliver to melanoma patients (index cases) the tip sheet and oral advice intended to their FDRs. The control group were asked to deliver the usual oral advice alone. The primary outcome was early detection of melanoma in FDRs with a medical TCE performed within one year after the first visit of the index case. Secondary outcomes were SSE and sun-related behaviors in FDRs. Results: A total of 48 index cases and 114 FDRS in the control group, 60 index cases and 166 FDRS in the intervention group were recruited. In the intervention group, 36.1% of FDRs performed a medical TCE as compared to 39.5% of FDRs in the control group (OR 0.9 [95% CI 0.5 to 1.5], p = 0.63). We did not find a between-group difference in SSE and sun-related behaviors. Conclusion: A tip sheet added to the usual oral advice did not increase medical TCE among FDRs of melanoma patients. Overall, the rate of TCE among FDRs was low. Research on other strategies is needed to increase melanoma detection in this population.