Purpose: To investigate the outcome following adjuvant doxorubicin and ifosfamide in a prospective non-randomised study based on a soft tissue sarcoma (STS) patient subgroup defined by specific morphological characteristics previously shown to be at a high-risk of metastatic relapse. The expected 5-year cumulative incidence of metastases in patients with this risk profile has previously been reported to be about 50% without adjuvant chemotherapy. Methods: High-risk STS was defined as high-grade morphology (according to the Federation Nationale des Centres de Lutte Contre le Cancer [FNCLCC] grade II-III) and either vascular invasion or at least two of the following criteria: tumour size amp;gt;= 8.0 cm, infiltrative growth and necrosis. Six cycles of doxorubicin (60 mg/m(2)) and ifosfamide (6 g/m(2)) were given. Postoperative accelerated radiotherapy was applied and scheduled between cycles 3 and 4. Results: For the 150 eligible patients, median follow-up time for metastases-free survival was 3.9 years (range 0.2-8.7). Five-year metastases-free survival (MFS) was 70.4% (95% confidence interval [CI]: 63.1-78.4) with a local recurrence rate of 14.0% (95% CI: 7.8-20.2). For overall survival (OS), the median follow-up time was 4.4 years (range: 0.2-8.7). The five-year OS was 76.1% (95% CI: 68.8-84.2). Tumour size, deep location and reduced dose intensity (amp;lt;80%) had a negative impact on survival. Toxicity was moderate with no treatment-related death. Conclusions: A benefit of adjuvant chemotherapy, compared to similar historical control groups, was demonstrated in STS patients with defined poor prognostic factors. Vascular invasion, tumour size, growth pattern and necrosis may identify patients in need of adjuvant chemotherapy. (C) 2018 Elsevier Ltd. All rights reserved.