Tumour volume changes following pre-operative radiotherapy in borderline resectable limb and trunk soft tissue sarcoma

AimsTo evaluate tumour volume changes after preoperative radiotherapy (PRT) for borderline operable soft tissue sarcomas (STS).Materials and methodsA retrospective review was performed of 68 patients who received PRT between December 2004 and July 2011. Endpoints were radiological response, surgical margins, local control and survival.ResultsMedian tumour size was 12.5 cm. Tumour location was extremity (87%), trunk (12%), and neck (1%). Commonest histological subtypes were myxoid liposarcoma (32%) and myxofibrosarcoma (16%). The majority of patients (88%) received 50 Gy in 25 fractions. Post-radiotherapy imaging was available in 55 cases. By RECIST there was stable disease in 89%, partial response in 7% and progressive disease in 4%. Tumour volumes reduced in 80%. Median change in maximal tumour dimension was −13.6%; median change in volume was greater, at −33.3%. Tumour volumes increased in 11 cases (20%). However, surgical margins were clear in all 11 cases, with no local recurrences in this group. For the entire group, surgical margins were clear in 93%, and microscopically positive in 7%. Eight patients (12%) had local relapse at 2–24.8 months after surgery. Two year local relapse free survival was 87.5%; 2 year overall survival was 74.7%.ConclusionThe majority of tumours showed reduction in volume. A small number of tumours increased in volume, but there was no definite relationship between volume increase and poor surgical outcomes or lower local control rates. Local control was equivalent to published series' of PRT. PRT is a reasonable approach in patients with borderline resectable tumours.