Local relapse of soft tissue sarcoma of the extremities or trunk wall operated on with wide margins without radiation therapy

BACKGROUND: The quality of surgical margins is the most important factor affecting local control in soft tissue sarcoma (STS). Despite this, there is no universally accepted consensus on the definition of an adequate surgical margin or on which patients should be offered radiation therapy. This study focuses on local control and its prognostic factors in patients with trunk wall and extremity STS. METHODS: Adult patients with a final diagnosis of trunk wall or extremity STS referred to a single tertiary referral centre between August 1987 and December 2016 were identified from a prospective institutional database. Patients were treated according to a protocol instituted in 1987. The classification of surgical margins and indications for radiation therapy were based on anatomy and strict definition of surgical margins as metric distance to the resection border. Local treatment was defined as adequate if patients received either surgery with wide margins alone or marginal surgery combined with radiation therapy. Margins were considered wide if the tumour was excised with pathological margins greater than 2.5 cm or with an uninvolved natural anatomical barrier. After treatment, patients were followed up with local imaging and chest X-ray: 5 years for high-grade STS, 10 years for low-grade STS. RESULTS: A total of 812 patients were included with a median follow-up of 5.8 (range 0.5-19.5) years. Forty-four patients had a grade 1 tumour: there were no instances of recurrence in this group thus they were excluded from further analysis. Five-year local control in the 768 patients with grade 2-3 STS was 90.1 per cent in patients receiving adequate local treatment according to the protocol. Altogether, 333 patients (43.4 per cent) were treated with wide surgery alone and their 5-year local control rate was 91.1 per cent. Among patients treated with wide surgery alone, deep location was the only factor adversely associated with local relapse risk in multivariable analysis; 5-year local control was 95.3 per cent in superficial and 88.3 per cent in deep-sited sarcomas (hazards ratio 3.154 (95% c.i. 1.265 to 7.860), P = 0.014). CONCLUSION: A high local control rate is achievable with surgery alone for a substantial proportion of patients with STS of the extremities or superficial trunk wall.