(P 53) CURATIVE-INTENT SURGERY FOR A SOLITARY ISOLATED BONE METASTASIS FROM EXTREMITY SARCOMA: WHO UNDERWENT METASTASECTOMY AND WHAT WAS THE PROGNOSTIC OUTCOME?

Location: The Liffey, Level 1

Author(s)

Liuzhe Zhang, MD (he/him/his)

Clinical fellow
Mount Sinai Hospital, Department of Surgery, University of Toronto, Toronto, Canada
Toronto, Ontario, Canada

Co-Author(s)

JM

Jean-Camille Mattei, MD

University Musculoskeletal Oncology Unit, Mount Sinai Hospital, Department of Surgery, University of Toronto, Toronto, Canada
Toronto, Ontario, Canada
AG

Anthony Griffin, MSc

Clinica Research Manager
Mount Sinai Hospital
Toronto, Ontario, Canada
KT

Kim Tsoi, MD, PhD

University of Toronto
Toronto, Ontario, Canada
PF

Peter Ferguson, MSc., MD

University of Toronto
Toronto, Ontario, Canada
JW

Jay Wunder, M.Sc, MD

University of Toronto
Toronto, Ontario, Canada

Objective: Approximately 40% of sarcoma patients will develop lung metastasis, and 10% will develop bone metastasis. The survival benefit of metastasectomy for solitary lung metastasis has been shown, but the role of surgery for solitary bone metastases remains unclear. We investigated the impact of curative-intent surgery on solitary bone metastasis from sarcoma.

Methods: This is a single-center retrospective cohort study. From 1987- 2019, 47 patients who underwent curative-intent treatment for localized extremity bone or soft tissue sarcoma developed a solitary bone metastasis as the first distant recurrence. The median age at the primary surgery was 46 years (Interquartile range [IQR], 35–60), and 51% (24/47) received curative-intent metastasectomy.
We compared the metastasectomy versus non-metastasectomy group characteristics and used the log-rank test and multivariate analysis to evaluate the impact of solitary bone metastasectomy. The primary outcome was overall survival after development of an isolated bone metastasis.

Results: After the first solitary bone metastasis, the metastasectomy group had longer overall survival in univariate analysis (median 43 vs. 11 months, p< 0.001; Figure 1). However, the metastasectomy group had fewer patients with metastasis in the spine or pelvis (58% vs. 96%, p=0.004) and a longer interval from primary sarcoma treatment to the identification of bone metastasis (median 28 vs. 13 months, p=0.03). In multivariate analysis, metastasectomy remained a positive prognostic factor for improved survival (HR 0.18, 95%CI 0.07 – 0.45, p< 0.001).

Conclusion: Curative-intent surgery for solitary bone metastasis from sarcoma is associated with a better prognosis and may be a reasonable treatment strategy whenever feasible. Future studies are needed to validate our findings and to investigate which patient group will benefit more from the surgery.