The emerging fifth epidemiologic subtype of Kaposi sarcoma in HIV-negative men who have sex with men at a tertiary care center in NYC from 2000 to 2021.

Abstract

11579 Background: Kaposi sarcoma (KS) is a vascular tumor caused by human herpesvirus 8, also known as Kaposi sarcoma herpesvirus. There are 4 widely accepted distinct epidemiologic subtypes of KS: classic, endemic, iatrogenic, and epidemic (HIV-associated) forms. An emerging 5th subtype is increasingly recognized: non-epidemic KS in men who have sex with men (MSM) who are HIV-negative and have no other known causes for immunodeficiency. Objectives: To characterize a cohort of non-epidemic KS seen at the Sarcoma Medical Oncology or Dermatology Clinics at Memorial Sloan Kettering Cancer Center in New York City from 2000 to 2021 to identify risk factors, presentation, treatment course, and prognosis of these patients. Methods: Following IRB approval, a retrospective observational study was performed. Eligible patients were identified through the Electronic Health Records (EHR). The patients were characterized based on age at presentation, sex, gender identity, comorbidities, coinfections, and treatments and outcomes amongst other factors. Study data were collected and managed using REDCap electronic data capture tools. Results: Seventy-two patients were identified. The median age at time of diagnosis was 58 (range: 32-83). At initial diagnosis, 46% (33/72) of patients underwent observation, 50% (36/72) received localized treatment (i.e. excision, cryotherapy or topical therapy), and 4% (3/72) received systemic treatment with chemotherapy. The median duration of follow-up was 22 months. In follow-up, 43% (31/72) of patients had progression of disease requiring recurrent treatment: 24% (17/72) received localized treatment while 18% (13/72) received chemotherapy. Patients who received chemotherapy, predominantly pegylated liposomal doxorubicin, received treatment for a median duration of 13 months (range: 2-72 months). By the end of the follow-up period, 7 patients had died, of which 2 deaths were attributed to KS. During follow up, 10% (7/72) of patients were diagnosed with a lymphoproliferative disorder. Conclusions: This study is the largest yet, to our knowledge, to characterize the non-epidemic KS subtype in HIV-negative MSM. It is important to recognize this KS subtype to identify these individuals, who despite not having HIV are at increased risk for KS. Accurate recognition of this subtype may also allay patient concerns regarding overall prognosis, given that the majority of these patients present with indolent disease and have favorable outcomes compared to the epidemic variant of KS. Additional research is needed to understand the potential increased risk of lymphoproliferative disorders.