Analysis of relationship between distance to diagnosing provider and Breslow depth at diagnosis

Abstract

6018 Background: Mediators of access to medical care, such as geographic isolation, rurality and socioeconomic status, have been associated with stage at diagnosis, treatment, clinical trial involvement and prognosis for various cancers. For melanoma, little is known about the relationship between mediators of access and various outcome measures. We hypothesize that Breslow depth at diagnosis is related to the distance patients travel to reach their diagnosing providers. Methods: An IRB-approved secondary data analysis was performed of all incident cases of invasive cutaneous melanoma in 2000 from a 42 county ascertainment area. Patients and physicians were geocoded to street address; Euclidian distances between patients and providers were calculated. The outcome variable, Breslow depth at diagnosis, was logged for analysis. Simple and multiple linear regression were used to test associations between Breslow depth and distance to provider, age, gender, census tract poverty rate, rurality and availability of local dermatologists. Results: Of 655 eligible cases, 6% were excluded for missing histopathologic data. Median Breslow depth was 0.6mm (mean 1.1±1.6; range 0.1–20.0mm). Median distance to provider was 8 miles (mean 15±31; range 0–386 miles). For every ten mile increase in distance, Breslow depth increased by 6% (p=0.002). For every 10% increase in poverty rate, the Breslow depth increased by 10% (p=0.041). The relationship between Breslow depth and age wasn’t linear: depth was 17% greater for patients 51–80 than for those ≤50 (p=0.016), while depth was 74% greater for patients >80 than for those ≤50 (p<0.001). Gender, rurality, and availability of local dermatologists were not significantly associated with Breslow depth. On multivariate analysis, the associations between Breslow depth at diagnosis and distance to provider (p=0.002) and age (p<0.015) were significant. Conclusions: Distance to provider may be a significant measure of access to melanoma care that captures different information than proxy measures of rurality, poverty, and local availability of providers. Further research is needed to elucidate factors that mediate how far patients travel to reach their diagnosing providers. No significant financial relationships to disclose.