The Treatment and Outcomes of Extraskeletal Osteosarcoma: Institutional Experience and Review of The Literature

Abstract

Background: Extraskeletal osteosarcoma is a rare tumor with a poor prognosis. The purpose of this study is to examine the oncologic outcomes of this disease as they relate to surgical treatment and use of adjuvant therapies.

Methods: We retrospectively analyzed all patients treated at our institution for high-grade extraskeletal osteosarcoma of the limb or chest wall. We recorded demographic data, presenting stage, surgical margin, use of adjuvant chemotherapy or radiation, incidence of local recurrence, metastases, and death. Overall and event-free survival were calculated using Kaplan-Meier survival methods.

Results: There were 12 patients treated with primary wide resection or re-excision of a previously operated tumor bed. Four patients presented with metastases. Seven patients received chemotherapy and four patients received radiation therapy. There were two local recurrences, six patients developed new metastases, and nine patients died. There was no difference in overall survival in patients who received chemotherapy. There was, however, a trend towards increased length of survival in patients who received chemotherapy compared to those who did not (16.4 months vs. 9.3 months, p=0.16).

Conclusions: Despite no difference in overall survival, patients treated with adjuvant chemotherapy have a trend towards increased length of survival. We suggest that extraskeletal osteosarcoma be treated with standard osteosarcoma chemotherapy regimens in addition to wide resection.

Figure 1.

(a) Plain radiographic image demonstrating an ossific mass in the region of the right hip. (b) Axial T1 post-contrast MRI demonstrating the mass arising from the right gluteal musculature with a thin peripheral rim of enhancement. (c) Positron emission tomography scan demonstrating the mass with very high standardized uptake value. (d) Hematoxylin and eosin slide demonstrating immature osteoid formation by malignant appearing spindle cells.

Figure 2.

Kaplan-Meier survival plot of overall survival (OS) for the twelve patients in this series.

Figure 3.

Kaplan-Meier survival plot of OS in patients who received chemotherapy compared to those who did not.

Figure 4.

kaplan-meier analysis of event-free survival (efs) for the entire patient cohort.