Localized Myxofibrosarcoma: A Retrospective Analysis of Primary Therapy and Prognostic Factors in 134 Patients in a Single Institution.

ABSTRACT

BACKGROUND: Primary therapy of localized myxofibrosarcoma (MFS) remains controversial. Primary resection is complicated by a high rate of local recurrence, and the refractoriness to non-surgical treatment results in a higher risk of metastasis. The aim of the present study was to contribute the findings of a single sarcoma-specialized center and encourage investigating new treatment options. PATIENTS AND METHODS: We analyzed 134 patients treated with localized MFS in our center regarding prognostic factors defining overall survival, local recurrence, and metastasis. We focused on multimodal treatment of localized MFS surgery, radiation, chemotherapy, hyperthermia, and isolated limb perfusion. RESULTS: The 5-year OS was 74.9%. From a total of 134 patients 74 (55.2%) stayed disease free, 48 (35.8%) had a local recurrence (LR), and 23 (17.2%) developed a distant metastasis (DM). The 5-year LR-free survival (LRFS) and DM-free survival (DMFS) were 66.1% and 80.8%, respectively. Older age, tumor size (cT) cT ≥ 2, non-extremity localization, and distant metastasis were adverse predictive factors for OS. Performing an incision biopsy, surgery in a sarcoma-center, wide local excision or compartment-oriented excision, negative margins, and radiotherapy were positive predictive factors for LR. Tumor size cT ≥ 3 was a negative predictive factor for DM. Grading was a negative predictive factor for LR (G ≥ 2) and for DM (G3) in the multivariable analysis. CONCLUSION: Adjuvant radiation had a positive impact on LRFS in all localized tumor stages, even in cT1 tumors. Chemotherapy did not have a significant impact on DMFS, regardless of tumor stage. Our findings indicate that myxofibrosarcoma may be a chemotherapy-resistant entity and a much closer monitoring is required, in case of neoadjuvant treatment.