Evaluation of prognostic factors and oncological outcomes in patients with limb-localized myxoid liposarcoma

OBJECTIVES: This study aims to evaluate the prognostic factors and treatment outcomes of patients with extremity-localized myxoid liposarcoma (MLS). PATIENTS AND METHODS: Between January 2001 and October 2019, a total of 43 patients (29 males, 14 females; mean age: 56.3±11.4 years; range, 34 to 76 years) who were histopathologically diagnosed with MLS in our clinic were retrospectively analyzed. Data including demographic characteristics, tumor localization, tumor volume and length, histopathological characteristics, the surgery and chemotherapy (CT)/radiotherapy (RT) applied, survival rates, and complications such as local recurrence and metastasis were recorded. The treatment results and potential prognostic factors were identified. The overall survival (OS) and cancer-specific survival (CSS) rates were evaluated. RESULTS: The mean follow-up was 106.8±54.1 (range, 29 to 204) months. The mean tumor size was 11.4±6.5 (range, 4.7 to 36) cm. Tumor localization was determined as lower extremity in 76.7% of cases and upper extremity in 23.2%. The patients were divided into two groups according to the type of RT they received as follows: the patients who underwent neoadjuvant RT + wide surgical resection (n=14, 32.5%) and patients who underwent extensive surgical resection + adjuvant RT (n=29, 67.4%). To four patients who developed distant metastasis and to two who developed local recurrence, adjuvant CT was applied. In the whole cohort, the OS rate was 87.1% at five years and 73.2% at 10 years. The five and 10-year CSS rates were 83.5% and 66.4%, respectively. Local recurrence developed in 12 (27.9%) and distant metastasis in four (9%) patients. In the multivariate analysis, high tumor grade, R2 margins, and metastasis were found to be independent risk factors for OS. Although wide resection provided significantly good local control, neoadjuvant RT and adjuvant CT were not found to be prognostic factors for OS or CSS (p>0.05). CONCLUSION: High tumor grade, R2 margins, and metastasis are independent risk factors for increased OS and OSS. Surgery with CT and neo/adjuvant RT is not an independent risk factor for OS or CSS. Despite patients with a larger tumor size and neurovascular proximity, similar disease-free survival rates can be achieved in the patients receiving neoadjuvant RT. Neoadjuvant RT can be considered in lesions close to neurovascular structures or in large lesions, with a high risk of wound complications.