Background: Myxoid liposarcomas (MLS) are intermediate to high grade liposarcomas, which are the most common type of soft tissue sarcoma. Although MLS most frequently develops in the legs, it can arise in any of the body’s soft tissue adipose. Previous studies of MLS survival have been limited in terms of geography, cohort size, variety of treatment settings, and assessment of primary site role. We retrospectively studied survival data for a nationwide cohort of MLS patients to identify prognostic factors and assess their effects on survival.
Methods: Using the National Cancer Database, we obtained data on 4636 patients diagnosed with MLS (ICD-O-3 8852) between 2004 and 2016. 5- and 10-year survival curves were estimated with Kaplan-Meier analysis and compared with log-rank analysis. Cox hazard regression was also used to compare multiple variables’ effects on survival.
Results: Approximately 59.2% of the cohort was male with a median age of presentation of 49 years. The most common site of metastasis was the bone followed by lung, liver, and brain. The majority (46.8%) of patients were stage I at time of diagnosis, followed by stage II with 18.1%, stage III with 13.1%, and stage IV at 5.3%. Overall 5- and 10-year survival probabilities for the cohort were 76.1% and 62.0%. Female patients (5-year: 79.6% and 10-year: 65.5%) had better survivals than male patients (5-year: 73.8% and 10-years: 59.6%). As stage increased, overall survival decreased with stage IV patients having 5- and 10-year survival probabilities of 21.2% and 9.4%, respectively. Patients with tumors localized to the extremities (5-year: 81.2%) had the best overall survival followed by tumors in the head or neck (5-year: 79.9%), pelvis (5-year: 77.3%), pelvis (5-year: 78.0%), thorax or trunk (5-year: 66.5%), and the retroperitoneum or abdomen (5-year: 53.1%). Finally, adjuvant radiation treatment correlated with decreased mortality to surgical resection of primary tumor alone (HR: 0.847; 95% CI: 0.726-0.989), whereas adjuvant chemotherapy correlated with increased mortality (HR: 2.769; 95% CI: 1.995-3.841).
Conclusion: Primary anatomical site was determined to be a major prognostic factor along with treatment facility type, sex, stage, and surgical margins for patients with myxoid liposarcoma.
