1753P - Outcomes of multidisciplinary treatment of localized myxofibrosarcoma: Retrospective analysis from a reference center

Background

Myxofibrosarcoma (MFS) are malignant tumors usually diagnosed in the extremities or trunk of elderly patients. Prognosis in this sarcoma subtype is dismal due to high risk of local recurrence. Our aim was to analyze the treatment results of patients (pts) diagnosed with localized myxofibrosarcoma, taking into account also surgical complications.

Methods

245 pts (51% male) with locally advanced myxofibrosarcoma treated in 2015-2020 were included in this retrospective analysis. Data on tumor characteristic and long-term survival and surgical complications were collected. Kaplan-Meier estimator with log-rank test was used for survival analysis. Median follow-up was 70 months (95%CI 67.2-79.7).

Results

The mean age was 63 years. 65% of the pts had no prior treatment, and 24% were referred after non-radical excision outside our center. Median size of the tumor was 9 cm (SD:6), 73% were high grade, 63% of cases were located on the lower limb (most often on the thigh). 82% had perioperative radiotherapy (72% preoperative). 22% of pts had preoperative chemotherapy. 76% pts underwent R0 resection, the others - R1. 56 pts (22%) had local recurrence and 29 of them had had another radical surgery, most of them extremity amputation (20 pts). 32% pts (79) developed metastases. Median OS was 115 months (95%CI 90.3-NA), while disease free-survival and local recurrence free survival (were 53.5 CI: (39.7 - NA) and not reached, respectively. In a multivariate analysis neoadjuvant radiotherapy was associated with longer LRFS (HR 0.36, 95%CI 0.21-0.65). T3 or T4 tumors and grade 2 or 3 tumors were associated with shorter DFS. Preoperative chemotherapy did not improve DFS (HR 0.82, 95%CI 0.51-1.33). 103 (42%) patient had complications after surgery resulting in prolonged wound healing, 40 of them had more than one complications, 10% patient required hospitalization due to complications, and 8.5% had another surgery for treatment of the complications.

Conclusions

Myxofibrosarcoma is a rare sarcoma subtype, local recurrences after adequate surgery are relatively common and most patient require adjuvant treatment and close follow-up. Treatment should be conducted in experienced sarcoma center with access to multidisciplinary team.

Clinical trial identification

Editorial acknowledgement

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.