(P 372) CLINICOPATHOLOGICAL FEATURES AND OUTCOMES OF PATIENTS WITH KAPOSI SARCOMA: A SINGLE CENTER RETROSPECTIVE REAL WORLD ANALYSIS

Objective: Kaposi sarcoma(KS) is a chronic, rare, multifocal angioproliferative neoplasm associated with immunodeficiency. Four clinical subtypes are recognized: classic KS(CKS), immunosuppression-associated KS, acquired immune deficiency syndrome(AIDS)-related KS, and endemic African KS. While often indolent and limited to the skin, KS can exhibit aggressive behavior. This study aims to characterize the clinicopathological features, treatment patterns, and outcomes of KS patients treated at the Instituto Português de Oncologia de Lisboa(IPOL) from 2004 to 2024.

Methods: We conducted a retrospective review of medical records from KS patients treated at IPOL between 2004 and 2024. Data collected included demographics, disease characteristics, treatment modalities, and clinical outcomes. Survival analyses were conducted using the Kaplan–Meier method.

Results: A total of 69 patients were included, of whom 88% were male. The median age at diagnosis was 69 years(range, 36–91), and 84% had an ECOG performance status of 0-1. The CKS subtype was the most common(81%) followed by AIDS-related KS(9%). At presentation, 46% had locally advanced or metastatic disease. Nodal and mucosal involvement were observed in 13% and 9% of cases, respectively. The lower limbs were the most frequently affected site(74%). Initial treatment modalities included surgery(64%), radiotherapy(30%), and chemotherapy(29%). Systemic treatment was administered to 45% of patients during their disease course, most commonly with pegylated liposomal doxorubicin(PLD, 78%), followed by paclitaxel(25%), and etoposide(25%). The median follow-up was 4.1 years. Median progression free survival was 2.3 years(95% CI,1.6-2.9), and median overall survival was 4.6 years(95% CI,0.2-21.3). Among 20 patients(29%) who received chemotherapy as first-line treatment, the objective response rate was 75%, including 3 complete and 12 partial responses. Systemic treatments were well tolerated, with only three reported cases of grade 3 toxicity(hematologic and neurologic).

Conclusion: This real-world, single-center study highlights the clinical heterogeneity of KS and the diversity of treatment approaches. Chemotherapeutic agents demonstrated encouraging efficacy and manageable toxicity profiles, particularly PLD. However, the disease often remains a chronic, relapsing disease requiring diverse treatment approaches. Given its rarity and complexity, optimal management benefits from a multidisciplinary approach to guide diagnosis, treatment, and long-term follow-up.