Trends in incidence, survival, and cause of death in Kaposi sarcoma in the antiretroviral therapy era.

Abstract

1563 Background: Kaposi sarcoma (KS) is a malignancy driven by human herpesvirus-8 infection and is most commonly associated with HIV. Although often considered indolent, KS can cause significant morbidity and mortality, particularly if HIV is uncontrolled. This study aimed to characterize current incidence and survival trends in KS using the Surveillance, Epidemiology, and End Results (SEER) Database. Methods: Cases of KS were identified using ICD-O-3 codes 9140-9143 in the SEER Research Plus Data (17 Registries, 2000-2022). SEER registry incidence rates were calculated over time. Overall survival (OS) across diagnostic eras was estimated using Kaplan-Meier methods. Multivariable Cox models were used to assess associations between race/ethnicity, neighborhood income, rural-urban status, and mortality, adjusting for age, sex, and year of diagnosis. Cause-of-death analyses were performed using SEER cause-specific recodes. Results: 9,931 patients with KS were identified, 91% male and 9% female. Racial and ethnic distribution was 45% non-Hispanic White (NHW), 24% Hispanic, 24% Black, 3.7% Asian/Pacific Islander (A/PI), and 0.7% American Indian/Alaska Native (AI/AN). Registry incidence of KS declined from 0.33 per 100,000 in 2000-2004 to 0.22 in 2015-2019 and 0.20 in 2020-2022. One-year OS in 2000-2004 was 77.3% (95% CI 75.7-78.9), in 2015-2019 was 82.2% (95% CI 80.4-83.9), and in 2020-2022 was 80.9% (95% CI 78.3-83.5). In multivariable analyses, Black patients had higher mortality compared with NHW patients (HR 1.55, 95% CI 1.43-1.67), while mortality did not differ significantly among Hispanic, A/PI patients, or AI/AN patients. Residence in the highest neighborhood income quartile was associated with improved overall survival compared with the lowest quartile (HR 0.81, 95% CI 0.73-0.89). Across 2000-2022, HIV/infectious causes accounted for 55.6% of deaths (95% CI, 53.9-57.2), followed by cardiovascular disease (15.1%) and cancer-related causes (13.3%). In cause-specific analysis, later year of diagnosis was strongly associated with lower HIV/infectious mortality (HR 0.96 per year, 95% CI 0.96-0.97), whereas mortality from cancer did not improve over time. Conclusions: In the modern antiretroviral therapy era, KS incidence and HIV-related mortality have declined. Despite these advances, inequities persist, with higher mortality observed among Black patients and persons residing in poorer neighborhoods. These findings highlight the need for focused efforts to address disparities in KS outcomes. Adjusted hazard ratios for overall survival in Kaposi sarcoma. Variable Adjusted HR 95% CI P value Race/Ethnicity Non-Hispanic White Reference - - Black 1.55 1.43-1.67 <0.001 Hispanic 1.02 0.95-1.11 0.54 Asian/Pacific Islander 1.02 0.86-1.20 0.82 American Indian/Alaska Native 1.26 0.89-1.80 0.20 Neighborhood Income Highest vs Lowest Quartile 0.81 0.73-0.89 <0.001