Malignant giant cell tumor of bone or soft tissue treated by surgery with or without radiotherapy

Malignant giant cell tumor of bone or soft tissue (MGCTBS) is one of the malignant tumors associated with poor prognosis. However, it remains controversial whether the combined treatment of both surgery and radiotherapy (surgery + RT) leads to better survival outcomes than surgical treatment alone (surgery alone) does for patients diagnosed with MGCTBS. We compared the two treatment strategies using the data provided by Surveillance, Epidemiology, and End Results (SEER) program. About 357 patients with MGCTBS who received either surgery + RT or surgery alone between 1975 and 2016 in the USA were identified and then matched based on their propensity scores estimated using the patients' baseline characteristics. We also performed a subgroup analysis for patients with high-grade and regional/distant tumor extension. Unadjusted Kaplan-Meier curves suggested that the surgery alone group had a better 10-year survival profile than the surgery + RT group. After propensity score matching, there was no statistical difference between the two treatment groups with respect to the 10-year cancer-specific survival and overall survival distributions. A subsequent subgroup analysis demonstrated that the surgery alone group has a similar 10-year survival comparing with the surgery + RT group for patients with high-grade and regional/distant tumor extension. The results of our study suggest that RT should not be recommended as a regular therapeutic method for MGCTBS, even for patients with high-grade histology and distant metastasis Clinical Significance: This study may provide better decision making for surgeons dealing with malignant giant cell tumor of bone or soft tissue. Type of study: Observation study. Level of evidence: Level III.