Analysis of clinical factors impacting recurrence in myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a malignant fibroblastic/myofibroblastic neoplasm with a prominent myxoid area. It has the clinical features of frequent local recurrence (LR) and occasional distant metastasis. Robust epidemiological data on MFS in China are lacking. The aim of this retrospective analysis was to determine the natural history of MFS, identify prognostic factors for recurrence and describe the real-life outcomes of MFS. We reviewed 52 patients with primary MFS from the First Affiliated Hospital of Nanjing Medical University diagnosed between 2016 and 2020. All tumors were subjected to retrospective univariate analysis for prognostic factors of the disease, including tumor size, grade, location and sex; patient age; planned operation; surgical margin; and laboratory results. The significant factors identified by univariate analysis were subsequently analyzed via multivariate analysis. Overall survival (OS), post-treatment LR and metastatic-free survival were assessed as outcomes. The median age was 61 years (range, 13-93). Fourteen (26.92%) patients exhibited low grade disease, and 38 (73.08%) exhibited high grade disease. Among the 29 males, and 23 females, 15 (28.85%) had tumors in the trunk, 37 (71.15%) had tumors in the extremities, 26 had undergone planned surgery, and 26 had unexpected unplanned operation. The margin was negative in 39 (75%) patients and positive in 13 patients (25%). The serum creatine kinase (CK) concentration was high level in 33 (63.46%) patients and low level in 19 (36.54%) patients. The serum lactate dehydrogenase (LDH) levels were low in 23 (44.23%) patients and high in 29 (55.77%) patients. LR was observed in 25 patients (48.08%), and 4 patients developed metastasis. A worse LR rate was found for patients with a low CK level (84.21%) than for those with a high CK level (27.27%) at 5 years (p < 0.05). The LR rate of patients who underwent planned surgery was lower than that of patients who underwent unplanned surgery (p < 0.05). There were significantly more patients with positive margins than patients with negative margins (92.30%, and 33.33%, respectively; p < 0.05). Moreover, superficial tumors were also associated with greater recurrence rate (2/20 [10%]) than deep tumors, (23/32 [71.86%]) [p < 0.05]. The probability of LR in patients with MFS was significantly greater in association with unplanned operations, positive margins, low serum CK levels or superficial tumor depth. These data could help identify high-risk patients; thus, more careful follow-up should be performed for higher-risk patients. Diagnosis and treatment at qualified regular medical centers can reduce the local recurrence rate of MFS.