78: Detection of Circulating Tumor DNA Predicts Recurrence in Soft Tissue Sarcomas

Thursday, March 23, 2023

11:36 AM – 11:46 AM

Location: Ballroom A

Abstract Presenter(s)

Beatrice J. Sun, MD

Resident
Stanford University School of Medicine
Stanford, California, United States

Disclosure(s): No financial relationships to disclose

First Author(s)

Beatrice J. Sun, MD

Resident
Stanford University School of Medicine
Stanford, California, United States

Disclosure(s): No financial relationships to disclose

Author(s)

Amy Y. Li, MD (she/her/hers)

Resident
Stanford University School of Medicine, United States

Disclosure information not submitted.
WA

Wilson Alobuia, MD

Resident
Stanford University School of Medicine, United States

Disclosure information not submitted.
DH

Dong Hur, BS

Medical Student
Stanford University School of Medicine, United States

Disclosure information not submitted.
Sara K. Daniel, MD (she/her/hers)

CGSO Fellow
Stanford University School of Medicine, United States

Disclosure information not submitted.
Amanda R. Kirane, MD, PhD-c, FACS, FSSO (she/her/hers)

Assistant Professor
Stanford University
PALO ALTO, California, United States

Disclosure information not submitted.
George Poultsides, MD (he/him/his)

Chief, Section of Surgical Oncology; Professor of Surgery
Stanford University
Stanford, California, United States

Disclosure(s): No financial relationships to disclose
Byrne Lee, MD (he/him/his)

Clinical Professor of Surgery
Stanford University School of Medicine
Stanford, California, United States

Disclosure information not submitted.

Disclosure(s):

Beatrice J. Sun, MD: No financial relationships to disclose

George Poultsides, MD: No financial relationships to disclose

Introduction: Soft tissue sarcomas (STS) exhibit a high rate of relapse. While systemic and local-regional therapies are improving, early detection of recurrence is limited to cross-sectional imaging. We aimed to evaluate whether the use of personalized circulating tumor DNA (ctDNA) profiling may aid in identifying recurrence and whether this could alter treatment paradigms.

Methods: A retrospective review of adult patients diagnosed with leiomyosarcoma, pleomorphic sarcoma, and dedifferentiated liposarcoma treated at a tertiary cancer center from 2019-2022 was performed. All patients had at least one ctDNA assay sent. These sarcoma subtypes were chosen due to their propensity for high mutational burden. ctDNA values were compared with imaging findings and medical records to determine whether ctDNA levels were predictive of disease recurrence. Alterations of previously planned surgical and medical treatments were also evaluated. ctDNA level and genomic profiling were obtained via a commercially available test.

Results: Forty-five patients with soft tissue sarcomas were included: 29 leiomyosarcoma, 9 pleomorphic sarcoma, 7 dedifferentiated liposarcoma. A total of 228 ctDNA assays were sent among the group. Twenty-nine out of 34 patients with documented disease progression or recurrence had ctDNA levels rise accordingly (sensitivity 85%). All 29 patients with positive assays had changes in their treatment plans. After treatment, ctDNA levels dropped in correlation with radiographic findings in 24 of the 29 patients (83%). All 11 patients with no known STS recurrence had no detectable levels of ctDNA (specificity 100%).

Conclusions: Recurrence in STS can be predicted in some patients utilizing ctDNA profiling to identify molecular (or minimal) residual disease. Early detection can lead to prompt treatment changes with potential for better outcomes. Further investigation is needed to determine which subgroups of STS will benefit from these assays. Additional evaluation of specific mutational signatures may aid in improving the performance of ctDNA assays (and developing tailored individualized treatment).

Learning Objectives:

Discuss role of ctDNA in cancer surveillance
Identify use of ctDNA assays to detect recurrence in soft tissue sarcoma
Discuss potential strategies for treating sarcoma recurrence