PATTERNS OF METASTASIS AND OUTCOME FOR PATIENTS WITH MYXOID LIPOSARCOMA

Abstract

Myxoid liposarcoma (MLS) is an unusual type of soft tissue sarcoma as it tends to metastasize frequently to sites other than the lungs. This study was aimed to investigate the natural history of patients with MLS to try and identify prognostic factors which could help predict outcome and aid earlier detection of metastases.

Data was prospectively collected from patient notes and analysed retrospectively. Prognostic factors and metastatic pattern were examined using Kaplan-Meier curves. There were 124 patients with MLS, aged between 28 and 93, the median size of the tumours was 12cm and the most common site was the thigh. Following treatment with excision and radiotherapy the 5yr survival was 65%. Survival was related to younger age (p=0.010) and proximal site (p=0.003) and was also related to the % round cell component of the tumour but was not related to either size or depth of the tumour. Site and margins of excision were significant prognostic factors for local recurrence of disease. 32% of patients developed metastases, of whom 18 cases (46.2%) developed pulmonary metastases and 21 (53.8%) developed extra pulmonary metastases. The sites of these varied hugely and was not significantly related to the site or size of the primary tumour. There was no difference in time to develop metastases or in overall survival between the two groups. Median survival following metastases was 24 months.

Although MLS has an unusual pattern of metastases the site of metastases does not predict a better or worse outcome. Intensive follow up for extraskeletal metastases is probably not justified until they become symptomatic.