The significance of size change of soft tissue sarcoma during preoperative radiotherapy.

AIM: To assess the significance of change in tumour size during preoperative radiotherapy in patients with soft tissue sarcoma (STS).
METHODS: A retrospective review of 91 cases with STS was performed. Inclusion criteria were localised extremity and truncal STS with measurable disease, older than 18 years, treated with preoperative radiotherapy and wide local excision, in the period between January 1966 and December 2005. Patients with head and neck STS, or who received neoadjuvant chemotherapy were excluded. A difference in excess of 10% of the greatest tumour diameter of the pre-radiotherapy and the post-radiotherapy MRI scans was considered as change in tumour size.
RESULTS: Increase in tumour size was noted in 28 patients (31%) (Group 1). No change or decrease in size was observed in 63 patients (Group 2). There were no significance differences in local control or overall survival rates between the 2 groups. The estimated overall actuarial local recurrence free, event-free and overall survival rates were 90.5%, 64.4%, 62.9% in Group 1, and 85.7%, 60.8%, 68.9% in Group 2 respectively.
CONCLUSION: Increase in tumour size during preoperative radiotherapy for soft tissue sarcoma does not seem to associate with inferior local tumour control or compromise survival. Lack of reduction in tumour size is not necessarily a sign of lack of response to preoperative radiotherapy.