Description
- Abstract:
- Background Melanoma is a highly aggressive skin cancer with rising incidence, especially among non-Hispanic White individuals.1 Early detection improves prognosis, but disparities in access to care, health literacy, and socioeconomic status influence stage at diagnosis.2 Although increasing early-stage diagnoses raises concern for overdiagnosis of indolent lesions,3-5 underdiagnosis in underserved populations can delay treatment and worsen outcomes.2,6 Geographic variation is well recognized; areas with better access to dermatologic services often show higher rates of early detection, while resource-limited regions face delays and more advanced disease.7 While cancer surveillance programs provide state-/county-level cancer risk data, no sub-county analysis of stage-stratified melanoma incidence has been conducted in Rhode Island. This study aims to identify high-risk geographic areas that may benefit from targeted interventions. Methods We retrospectively analyzed 3,058 melanoma cases diagnosed from 2004 to 2024 in the Brown University Health Tumor Registry. Inclusion required confirmed melanoma, known stage, a Rhode Island address, and self-identification as non-Hispanic White. Cases missing demographic, address, or staging data were excluded. Staging followed AJCC guidelines: early-stage (0 to II), late-stage (III to IV).8 Using National Cancer Institute population data, we calculated age-adjusted incidence rates and standardized incidence ratios (SIRs) by town and stage, applying a 95% confidence level to both. Spatial clustering was assessed via Anselin Local Moran’s I (LISA) in GeoDa software. Results Of 3,058 cases, 2,257 met inclusion criteria. The mean age at diagnosis was 64.3 years. Most cases (n=1,932; 85.6%) were early-stage; 325 (14.4%) were late-stage. Age-adjusted incidence rates varied across Rhode Island municipalities. The mean age-adjusted incidence rate for melanoma is 0.61 cases per 100,000 persons per year (interquartile range [IQR]: 0.45-0.71). The lowest rate was observed in Woonsocket (0.20, 95% CI: 0.13-0.30), whereas the highest rate was found in Portsmouth (1.11, 95% CI: 0.88-1.41). The early-stage incidence (mean: 0.53, IQR: 0.38-0.64) showed a similar pattern, reflecting the fact that the majority of cases were early-stage: the highest in Newport (1.00, 95% CI: 0.81-1.26) and again lowest in Woonsocket (0.16, 95% CI: 0.10-0.26). LISA clustering analysis identified a high-risk cluster of coastal towns (Portsmouth, Middletown, Newport, Narragansett, Jamestown) for both total and early incidence. The late-stage incidence (mean: 0.09, IQR: 0.06-0.11) demonstrated a distinct pattern, characterized by elevated risks distributed across the western rural/suburban towns. No significant clusters were identified for late-stage incidence. SIRs for total and early-stage melanoma identified seven towns with significantly elevated risk compared to the Rhode Island average. The high-risk towns include the coastal towns mentioned above and Barrington, with the highest in Newport (total SIR: 2.02, 95% CI: 1.66-2.41; early SIR: 2.17, 95% CI: 1.76-2.60). Late-stage SIR analysis suggested Barrington (SIR: 2.10, 95% CI: 1.05-3.32) is the sole town with significant excessive risk. LISA analysis of total SIRs revealed high-risk clusters (i.e., coastal towns) consistent with those found in the incidence analysis. No significant geographic clusters were found for early or late SIRs. Discussion Melanoma incidence varies substantially across Rhode Island, with notable disparities in both early and late-stage disease. Several towns showed significantly elevated or reduced SIRs, and early-stage clustering was identified in high-resource coastal communities. These findings highlight the impact of spatial and sociodemographic factors on melanoma detection, underscoring the need for equitable access to dermatologic care. Targeted screening, outreach in underrepresented areas, and improved access to dermatologic care may reduce late-stage melanoma and promote earlier diagnosis statewide.
- Notes:
- Scholarly concentration: Caring for Underserved Communities
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Citation
Danes, Emma, Hoffman, Victoria, Harikrishnan, Nikhil, et al.,
"The Geography of Melanoma: Exploring Staging Patterns in Rhode Island"
(2025).
Warren Alpert Medical School Academic Symposium.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/fzn9-5t09
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Warren Alpert Medical School Academic Symposium
The Warren Alpert Medical School Academic Symposium is an annual event at Warren Alpert Medical School of Brown University that provides Year II medical students a venue to present their summer research in a poster format. Participation in the Symposium …...