Aims. Patients with soft-tissue sarcoma (STS) who undergo unplanned excision (UE) are reported to have worse outcomes than those who undergo planned excision (PE). However, others have reported that patients who undergo UE may have similar or improved outcomes. These discrepancies are likely to be due to differences in characteristics between the two groups of patients. The aim of the study is to compare patients who underwent UE and PE using propensity score matching, by analyzing data from the Japanese Bone and Soft Tissue Tumor (BSTT) registry. Methods. Data from 2006 to 2016 was obtained from the BSTT registry. Only patients with STS of the limb were included in the study. Patients with distant metastasis at the initial presentation and patients with dermatofibrosarcoma protuberans and well-differentiated liposarcoma were excluded from the study. Results. A total of 4,483 patients with STS of the limb were identified before propensity score matching. There were 355 patients who underwent UE and 4,128 patients who underwent PE. The five-year disease-specific survival (DSS) rate was significantly better in the patients who received additional excision after UE than in those who underwent PE. There was no significant difference in local recurrence-free survival (LRFS) between the two groups. After propensity score matching, a new cohort of 355 patients was created for both PE and UE groups, in which baseline covariates were appropriately balanced. Reconstruction after tumour excision was frequently performed in patients who underwent additional excision after UE. There were no significant differences in DSS and LRFS between the patients who underwent PE and those who had an additional excision after UE. Conclusion. Using propensity score matching, patients with STS of the limb who underwent additional excision after UE did not experience higher mortality and local failure than those who underwent PE. Reconstruction may be necessary when additional excision is performed. Cite this article: Bone Joint J 2021;103-B(12):1809–1814

Aim. Local treatment of Ewing sarcoma of the hip bones and sacrum remains one of the most difficult tasks in the treatment of bone sarcomas. We investigated the difference between size, local treatment and overall survival in Ewing sarcoma of the sacrum and hip bones. Methods. Patients with Ewing sarcoma of the hip bones or sacrum, diagnosed between 1986 and 2009, were identified through the Scandinavian Sarcoma Group registry. Data regarding tumour size, local treatment (radiation or surgery), local recurrence, surgical margin, metastatic disease, and overall survival were analyzed and compared between the two locations (hip bone or sacrum). Results. 99 patients with Ewing tumour in the hip bones (74 patients) or the sacrum (25 patients) were identified. The mean size was 7.8 cm (sacrum) and 10.6 cm (hip bones), p=0.007. For tumours localised to the sacrum, 9% of the patients underwent surgery, 68 % received radiotherapy and 5% received both. For patients with tumours in the hip bones, 28% underwent surgery, while 32% received radiotherapy and 28% received both. All of the 6 patients with local recurrence died. There was a tendency (p=0.059) for better overall 5 year survival for patients with a tumour localised to the sacrum compared with patients with a tumour localised to the hip bones (58 vs. 32%). Conclusion. Ewing tumours are smaller in the sacrum than in the hip bones. Radiotherapy alone appears to give sufficient local control of Ewing sarcoma of the sacrum. Ewing sarcoma of the sacrum most probably has a better prognosis than Ewing sarcoma of the hip bones