Multivariate Survival Analysis of Adult Skin Cancers in Florida (1981-2009)

Introduction: Skin cancer (SC) is the most common cancer in the US; 1-in-5 develops it in their lifetime. The rates have increased steadily over the past few decades worldwide. The increasing incidence in SC is a public health threat and warrants study to determine which groups carry the greatest burden of mortality due to skin cancer. We report the demographics and survival trends of SC from 1981 to 2009 in the Florida adult population (>=18 yrs) to study disparities between certain ethnic, racial, gender, and socioeconomic (SES) groups and mortality due to skin cancer.

Methods: The Florida Cancer Data System (1981-2009) was linked with US census to explore median survival and 5-year survival rates by sociodemographics for all SC. Survival was compared by type, gender, race, ethnicity, SES and modeled with multivariate Cox regression to calculate adjusted hazard ratio (AHR) and 95% confidence interval (95%CI).

Results: There were 80,924 patients with SC where 67% malignant melanoma (MM), 19% UV-related, and 14% other types of skin cancer including 2.4% Merkel Cell Carcinoma (MCC). The majority were male (59.3%), White (99%), middle-high/highest SES (75%), living in urban (95%) and had localized cancer (53%). Overall median survival was 4.5 yrs (95%CI:4.5-4.6) including MM (4.8), UV related (5.5). Higher median survival time was seen in White (4.5) than Black (3.4), female (5.4) vs. male (4.1) and non-Hispanic (4.5) vs. Hispanic (3.9). The 5-yr survival rates were higher in UV-related SC (54.3%) than MM (48.7%), White (46.8%) vs. Black (35.4), non-Hispanic (46.8%) vs. Hispanic (42.5%), female (52.6%) vs male (43.3%). Compared to MM, MCC ([AHR =1.35];1.24–1.46) and other skin cancer subtypes ([1.13];1.08–1.18) had significantly worse survival, but UV-related SC ([0.87];0.84–0.9) had better survival. Significantly worse survival was seen in Black vs. White ([1.3];1.11–1.53), and females showed better survival compared to males ([0.78]; 0.76–0.81). Current smokers ([1.24];1.18–1.31) and those with a history of smoking([1.05];1.01–1.09) showed worse survival compared to those who had never smoked.

Conclusions: There are survival disparities in skin cancer across types, ethnicities, races, genders, and SES. This study identifies groups with the highest skin cancer mortality burden in addition to high-risk types of skin cancer.