Fifth subtype of Kaposi sarcoma in HIV-negative MSM: a retrospective single-arm cohort study from a tertiary care center in NYC from 2000 to 2022.

Abstract

Background: Kaposi sarcoma (KS) is a vascular tumor caused by human herpesvirus 8, also known as Kaposi sarcoma herpesvirus. There are 4 distinct subtypes: classic, endemic, iatrogenic, and epidemic (HIV-associated). A fifth subtype is increasingly recognized: non-epidemic KS in men who have sex with men (MSM) who are HIV-negative. Our primary objective was to characterize non-epidemic KS to identify associated risk factors, presentation, treatment course, and prognosis of these patients.

Patients and methods: This retrospective cohort included all patients evaluated at Memorial Sloan Kettering Cancer Center from 2000 to 2022 with pathologically proven KS who identified as MSM status, without diagnosis of HIV. Data were collected on demographics, comorbidities, coinfections, treatments, and outcomes.

Results: Seventy-two patients were identified. The median age at the time of diagnosis was 58. At initial diagnosis, 44% of patients underwent observation, 51% received localized treatment and 5% received systemic treatment. In follow-up, 47% of patients had a progression of disease requiring recurrent treatment: 25% received localized treatment while 18% received chemotherapy. In follow-up, 7 patients died, with only 2 deaths attributed to KS; 10% of patients were diagnosed with a lymphoproliferative disorder.

Conclusions: This study is the largest yet to characterize the non-epidemic KS subtype in HIV-negative MSM. These individuals are younger, HIV-negative, MSM with a favorable prognosis. Additional research is needed to understand the potential risk associated with lymphoproliferative disorders.