Emerging Nonepidemic Kaposi Sarcoma Subtype Shows Favorable Outcomes According to Study

Nonepidemic Kaposi sarcoma (KS) in men who have sex with men who are not living with HIV and have no other known causes for immunodeficiency, an emerging fifth subtype of KS, has been characterized in the largest study yet, conducted by researchers from Weill Cornell Medical College.

These results were presented at the recent American Society of Clinical Oncology Annual Meeting.

Their overall findings show patients with this KS subtype present with indolent, or slow-growing, disease and have favorable outcomes.

KS is a vascular tumor cause by human herpesvirus 8 (KS herpesvirus). This subtype differs from the 4 widely accepted epidemiologic subtypes of KS: classic, endemic, iatrogenic, and epidemic, or HIV-associated, forms.

“It is important to recognize this KS subtype to identify these individuals, who despite not having HIV are at an increased risk for KS,” wrote the authors.

A retrospective observational study was conducted to categorize a cohort 72 patients who had nonepidemic KS and were receiving care at the Sarcoma Medical Oncology or Dermatology Clinics at Memorial Sloan Kettering Cancer Center in New York City from 2000 to 2021. The median age at time of diagnosis was 58 (range, 32-83) years, and the median duration of follow-up was 1.95 (range, 0-17) years.

IRB approval was obtained, and electronic health records were reviewed to identify risks factors, presentation, treatment course, and treatment of the patients studied. Patients were characterized based on age at presentation, sex, comorbidities, coinfections, and treatments and outcomes.

Following initial diagnosis, the following treatments were administered:

• 46% of patients underwent observation
• 50% received localized treatment (ie, excision, cryotherapy, or topical therapy)
• 4% received systemic treatment with chemotherapy

During follow-up, 43% of patients had disease progression that required recurrent treatment:

• 24% received localized treatment
• 18% received chemotherapy

Findings showed 5-year progression-free survival was 39% for those requiring recurrent treatment, as well as 83% overall after 10 years—which was higher than historical data at 65% for all men with KS reported by SEER data.

Patients who received systemic chemotherapy received treatment for a median of 13 (range, 2-72) months, and the most common regimen was pegylated liposomal doxorubicin. The overall median duration of chemotherapy (localized and systemic) was 14.5 (range, 3-60) months.

Additionally, 10% of patients had evidence of a lymphoproliferative disorder as a preexisting condition, concurrent with KS diagnosis, or detected during active surveillance.

By the end of the follow-up period, 7 patients had died. Of these patient deaths, 2 were attributed to KS.

“The 10-year survival for all-cause mortality was higher than historical data for all men with KS reported by SEER data,” concluded the authors. “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.”

Reference

Morales AE, Benson G, Glavan S, Giuliano R, Dickson MA. 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 presented at: 2022 American Society of Clinical Oncology Annual Meeting; June 3-7, 2022; Chicago, IL. Abstract 11579. Accessed June 16, 2022. https://meetings.asco.org/abstracts-presentations/211407