Demographic, clinical, and social characteristics of anal cancer among patients stratified by age (<50 and ≥50 years) in Alabama between 2012 and 2018.

BACKGROUND

Anal cancer is increasing globally, with a high number of new cases occurring in highly developed countries, including the U.S. The incidence of anal cancer is higher among people living with HIV (PLHIV), and the U.S. South continues to see higher HIV incidence rates and lagging HPV vaccination rates. We aimed to identify factors associated with early onset anal cancer in Alabama which may help explain cancer disparities in the South.

METHODS

Using a cross-sectional study design, we examined demographic, clinical, and social characteristics among anal cancer patients stratified by diagnosis age (<50 and ≥50 years) in the Alabama cancer registry between 2012 and 2018. We used Wilcoxon rank sums and Pearson chi-square tests to assess associations between age at diagnosis, demographic (i.e., sex, race, marital status), clinical (i.e., BMI, HIV infection, site, stage, and histological type), and social (i.e. social vulnerability) characteristics, and multivariable logistic regression to estimate the odds of early onset cancer.

RESULTS

Among 519 patients with anal cancer in Alabama, 92 (17.7 %) were diagnosed at <50 years. The majority of patients were female (66.5 %) and White (83.4 %). Male sex, Black race, and HIV infection were associated with younger age at diagnosis. Black patients had a 4-fold increased odds of early onset anal cancer compared to White patients (AOR=4.39, CI=1.54-12.49). Black patients disproportionately lived in areas with higher social vulnerability. About 42 % of patients in areas with the highest social vulnerability were diagnosed with stage 3 or 4 cancer. About 8 % of cases were among people aged 35-44 years, which is close to double the proportion of anal cancer cases in this age group in the U.S. (4.7 %).

CONCLUSIONS

Patients who are Black, male, and PLHIV may be at higher risk of early onset anal cancer compared to other populations in the South.