START VALID Project: Soft Tissue sARcomas of the extremiTies - VALIDation of follow up practice in the West of Scotland

Introduction: Soft issue sarcomas (STSs) are rare tumours treated with surgical resection as the mainstay of treatment. Current national STS follow- up imaging guidelines are for MRI scan of primary site up to five years post treatment, with 6 monthly scan in the first two years and annual thereafter. By examining our population of patients with STS we aim to report the incidence of local recurrence and validate current follow-up practice. Methods: The electronic clinical records of patients treated for STS in the West of Scotland were interrogated. Data was extracted from clinical letters, pathology and radiology reports. Results: 211 patients were identified, 89 patients are analysed at this stage, 11 patients were excluded because they had M1 disease at presentation(n=9); or were lost to follow up(n=2), leaving 78 patients. Local recurrence occurred in 8 patients(10.26%); median age 61.5(range 45-88); all high risk; 5 patients had postoperative and 1 patient preoperative radiotherapy. 6 had local recurrence only(7.69%), of which 5 were symptomatic; 1 was asymptomatic. 2 patients had local recurrence and distant relapse(2.56%), 1 was symptomatic; 1 was asymptomatic. The mean time to recurrence was 32.38 months (range 6 -108, mean 21.57) Conclusions: Symptomatic local recurrences were more common than asymptomatic local recurrences. Both asymptomatic recurrences were picked up in year 1. The mean time to recurrence was within five years and when adjusted to exclude the outlier, the mean and median time was in year 2 - suggesting current guidelines are suitable. We will report results for whole cohort of patients in the final abstract.