(P 404) OUTCOMES OF NEOADJUVANT THERAPY IN ANGIOSARCOMA PATIENTS: A KAPLAN-MEIER-RECONSTRUCTED INDIVIDUAL PATIENT-LEVEL META-ANALYSIS

Author(s)

IM

Isabella Michelon, MD

MD
Department of Medicine, Catholic University of Pelotas, Brazil
Pelotas, Rio Grande do Sul, Brazil

Co-Author(s)

GG

Gabriela Gazzoni, MD

Institute of Medical Assistance to the State Public Servant (IAMSPE), São Paulo, Brazil
Sao Paulo, Sao Paulo, Brazil
Isadora Mamede, MD (she/her/hers)

Medical Doctor
Federal University of São João del Rei, Divinópolis, Brazil
Divinopolis, Rio de Janeiro, Brazil
WC

Wellington Carneiro, n/a

Universidade de Fortaleza (UNIFOR)
Fortaleza, Ceara, Brazil
WK

Wallace Klein Schwengber, n/a

Department of Internal Medicine, Mayo Clinic, Phoenix, Arizona
Phoenix, Arizona, United States
AS

Anderson Simões, MD

Federal University of São Paulo, São Paulo, Brazil
Sao Paulo, Sao Paulo, Brazil
Ruyun Jin, MD, M.C.R. (she/her/hers)

Senior Biostatistician
University of Virginia School of Medicine, Department of Public Health Sciences, Charlottesville, VA, USA
Charlottesville, Virginia, United States
HZ

Hong Zhu, PhD

University of Virginia School of Medicine, Department of Public Health Sciences, Charlottesville, VA, USA
Charlottesville, Virginia, United States
RW

Russell G. Witt, MD

Assistant Professor
University of Virginia
Charlottesville, Virginia, United States
Steven Attia, DO

Consultant
Mayo Clinic in Florida, Jacksonville, FL, USA
Jacksonville, Florida, United States
LC

Ludimila Cavalcante, MD

Dr
Division of Hematology and Oncology, University of Virginia Comprehensive Cancer Center, Charlottesville, Virginia, USA
Charlottesville, Virginia, United States

Objective: The benefit of neoadjuvant therapy (NAT) in angiosarcoma (AS) patients remains unclear due to limited available evidence and the rare nature of this disease. We evaluated the impact of NAT in an individual patient-level meta-analysis using reconstructed Kaplan-Meier data from over 1,000 AS patients.

Methods: We searched three databases for studies exploring NAT in primary/secondary AS. Analyses included patients who did (NAT group) or did not (non-NAT group) receive NAT. We evaluated disease-free survival (DFS), distant metastasis-free survival (DMFS), and overall survival (OS) using Cox proportional hazards models, reporting hazard ratios (HRs) with 95% confidence intervals (CIs). The proportional hazards assumption was violated in all models (Grambsch-Therneau test, p< 0.05). Accordingly, we performed landmark analyses and restricted mean survival time (RMST). Analyses were conducted on R (v.4.2.2).

Results: Six studies met our eligibility criteria. Out of 1,112 AS patients included, 243 (21.9%) received NAT and 869 (78.1%) did not. Most NAT patients had primary cutaneous AS (84.4%), and breast was the most common site (40.7%). All but one study explored systemic NAT regimens. Taxane-based regimens were commonly administered (64%, n=75/117; three studies). Patients on NAT had a 24% (HR: 0.76, 95% CI 0.60-0.98, p=0.03) and 39% (HR: 0.61, 95% CI 0.45-0.81, p=0.0001) lower risk of disease recurrence and death, respectively, compared to non-NAT. The DMFS was nonsignificant (HR, 0.80, 95% CI 0.59-1.07, p=0.13). In the first 24 months (mos) after treatment, a significant DFS (HR: 0.70, 95% CI 0.52−0.94, p=0.016) and OS (HR: 0.27, 95% CI 0.13-0.55, p=0.00001) benefit were observed for NAT. The OS benefit was sustained in the following mos (landmark analysis up to 60 mos, HR, 0.48; 95% CI 0.35−0.67, p< 0.0001). The RMST analysis up to 60 mos revealed longer mean survival times in the NAT group compared to non-NAT across all three outcomes (p < 0.03, Table 1).

Conclusion: This study suggests a strong survival benefit of NAT compared to non-NAT in AS patients.

RMST up to 60 mos.
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