Clinical Presentations and Decreasing Incidence of Melanoma in Pediatric and AYA Patients: 76,108 Cases from a Nationally Representative Cohort.

Background: Knowledge of melanoma presentations among pediatric and adolescent and young adult (AYA) patients are limited due to studies with small sample sizes.

Objective: To determine the incidence trends and melanoma presentations based on age, sex, race and ethnicity using a large cohort of diagnoses from 1997-2020.

Methods: A retrospective cohort study was completed using the National Childhood Cancer Registry (NCCR) from 1997-2020.

Results: Incidence rates were 1.74 (95% CI 1.64-1.84) and 62.05 (95% CI 61.6-62.5) per one-million-person years for pediatric and AYA patients, respectively. Females encompassed 62.3% of the cohort. Non-Hispanic White patients represented 87.5% of all diagnoses, with significantly higher incidence rates of melanoma compared to all other racial and ethnic groups in both age groups, respectively (p <0.001; p < 0.001). Superficial spreading was the most common of the specified histologic subtypes. The most common location in pediatric patients was the lower extremity, compared to trunk in AYA. There were statistically significant differences in the distributions of primary tumor location by sex, as well as by race and ethnicity, in both pediatric and AYA groups.

Limitations: Limitations in this study include retrospective data, selection, and miscoding from individual registries.

Conclusion: There are significant differences in tumor characteristics among pediatric and AYA patients with cutaneous melanoma. Trends in incidence rates are decreasing for young patients diagnosed with cutaneous melanoma.