Metastatic Pattern, Local Relapse, and Survival of Patients with Myxoid Liposarcoma: A Retrospective Study of 45 Patients

Purpose. To assess the metastatic pattern of the histological subtype myxoid liposarcoma (MLS) with no or few round cells. Methods. Forty-five patients (F/M？=？27/18, mean age 49 (range 17–85) years) were diagnosed with MLS at two Danish sarcoma centres in the period 1995–2004. A retrospective review of patients' files combined with an extraction of survival data from the Danish Centralised Civil Register was performed. Results. Seven patients had distant metastases during the observation period. Two patients had metastases at the time of diagnosis, while metastases occurred within 2.5 years in four patients, and in one patient 11.9 years after primary diagnosis. All metastases occurred at extrapulmonary sites. The first local relapse occurred within 3 years after surgery in six patients, in one patient after 4.0 years, and in one patient 7.7 years after surgery. The 5- and 10-year overall survival was 80% and 69%, respectively. Both the 5- and 10-year distant metastases-free survival was, respectively, 86%. The 5- and 10-year local relapse-free survival was, respectively, 83% and 80%. Conclusions. Patients with MLS had only extra-pulmonary metastases, and no lung metastases were found. Most local relapses and distant metastases occurred within the first 2-3 years after surgery. 1. Introduction Sarcomas are very rare tumours and comprise approximately 1% of all newly diagnosed cancers [1]. The incidence is around 6 per 100,000 and has been rather constant during the last many years [2]. Liposarcomas are the second most frequent type of soft tissue sarcoma (STS), comprising 15–20% of all STS [3], and 30% of all liposarcomas are of the myxoid or myxoid round cell liposarcoma subtype [4, 5]. Originally, the myxoid and round cell liposarcomas (RCLS) were looked upon as two different histological subtypes but are now considered to represent a continuum of the same type, and the occurrence of areas with round cells is well known to be a poor prognostic factor [4]. STS has a tendency to, for most of the histological types, to metastasise haematogenously to the lungs whereas metastases to lymph nodes are uncommon [6]. Therefore, most guidelines recommend X-ray or computed tomography (CT scan) of the chest as the preferred method for evaluation of metastatic disease in the postoperative follow-up period [7–9]. Previously published studies have shown that the metastatic pattern in liposarcoma and especially myxoid liposarcoma (MLS) also includes extrapulmonary sites [10–18]. The purpose of this study was to evaluate the metastatic pattern, local relapse, and