Risk factors for the development of acral melanoma: A multi-institutional, retrospective cohort study.

BACKGROUND

Acral melanoma (AM) is a rare but aggressive melanoma subtype. Understanding demographic and clinical risk factors is essential for advancing prevention and early detection.

OBJECTIVES

To identify demographic and clinical risk factors for AM compared with nonmelanoma and cutaneous melanoma (CM) controls.

METHODS

This multi-institutional retrospective cohort study of patients evaluated at the Mass General Brigham and Dana-Farber Cancer Institute. Three cohorts were created via manual curation of pathology reports: AM cases, nonmelanoma controls, and CM controls. AM patients were matched 1:4 to controls based on pre/postindex follow-up time and dermatologic care history. Multivariable logistic regression and structural equation modeling assessed direct and indirect pathways linking sex, actinic keratoses, and melanoma subtype.

RESULTS

A total of 2115 patients were analyzed. AM patients were more often female and disproportionately Asian or Black compared with both controls. Relative to non-melanoma controls, AM was associated with female sex, Asian, or Black race, leukemia/lymphoma, nonmelanoma skin cancer, and actinic keratoses. Similar findings were present against CM controls.

CONCLUSIONS

AM risk is associated with female sex, Asian or Black race, and select prior malignancies. Findings demonstrate an association between markers of UV exposure (actinic keratoses) and AM risk, though significantly weaker than in CM. These insights may guide prevention, risk stratification, and mechanistic research.