The impact of longitudinal surveillance on tumor thickness for melanoma-prone families with and without pathogenic germline variants of cdkn2a and cdk4

Abstract

Background: Skin cancer screening is routinely performed for members of melanoma-prone families, but longitudinal studies evaluating the efficacy of surveillance in this high-risk population are lacking. Methods: We evaluated thickness for first primary melanomas diagnosed in melanoma-prone families (≥2 individuals with melanoma) enrolled in NCT00040352 (NCI familial melanoma study) from 1976 through 2014; enrolled patients received routine skin cancer screening and education about skin self-exams. We used linear and ordinal logistic regression models adjusted for gender and age with a generalized estimating equations approach to report changes in thickness and tumor (T) stage over time, comparing outcomes for NCI cases diagnosed before (pre-study) versus after study participation (prospective) and for NCI cases versus nonfamilial cases [Surveillance, Epidemiology, and End Results (SEER) 9 registries]. Results: Tumor thickness was evaluated for 293 NCI (pre-study = 246; prospective = 47) patients. Compared with NCI pre-study cases, NCI prospective melanomas were thinner (0.6 vs. 1.1 mm; P < 0.001) and more likely to be T1 stage [39/47 (83%) vs. 98/246 (40%); P < 0.001]. Similar findings (P < 0.05) were observed for familial cases with and without germline CDKN2A and CDK4 mutations. Peters.Belson modeling suggested that calendar period effects of decreasing thickness in the general population (SEER 9) did not fully explain thickness trends in NCI families. Conclusions: Participation in a longitudinal surveillance program providing skin cancer screening and education about skin selfexams was associated with thinner melanomas for members of melanoma-prone families. Impact: The study findings support the clinical benefit of screening (physician and self) for this high-risk population.