(P 196) TOLERABILITY AND OUTCOMES FOR TREATMENT OF OLDER MYXOID LIPOSARCOMA POPULATION

Objective: Myxoid liposarcoma (MLPS) has highest incidence in middle age. Little is known regarding treatment and outcomes in older patients (pts). This study aims to better understand this older pt population.

Methods: Chart review was performed of pts aged 70 years and above with non-metastatic MLPS between 1992 to 2021 who were seen at an academic sarcoma center. Analysis was performed on pts with at least two years (yrs) of follow up.

Results: Twenty pts with MLPS were identified, with a median age of 74 yrs (range 70 to 89) at diagnosis (Table 1). Over half were female (11, 55%). Most tumors were extremity in location (16 pts, 80%) with median tumor size of 11 cm (3.6 to 30 cm). Seven pts (35%) had round cell component (percentage not reported).

Eighteen of 20 pts (90%) received perioperative radiation. Over half had postoperative radiation (10 pts, 55%). One of 8 pts who received preoperative radiation developed metastasis prior to planned resection. Only 1 of 19 patients who underwent surgery developed a postoperative wound complication. Three pts (15%) with high grade disease received perioperative chemotherapy.

The median follow-up from surgery was 75 months (mos) (5-239). Eleven (55%) pts died from MLPS. The median progression free and overall survival were 39 mos (3-76) and 62 mos (5-108), respectively. Four of 7 pts (57%) with a round cell component died from their disease.

The median survival after relapse was 9 mos (0-32). Ten pts had distant metastasis (most commonly to bone), and one had local relapse (to retroperitoneum). Two pts (18%) had additional surgery. Five (45%) had RT and six (55%) had systemic therapy for relapse. Pts had minimal side effects from RT, mainly fatigue, gastrointestinal side effects, and erythema of RT site. Systemic therapies included: doxorubicin alone or in combination with ifosfamide, olaratumab, or mitomycin C/cisplatin; trabectedin, gemcitabine, ifosfamide/etoposide, nivolumab. One patient stopped trabectedin due to toxicity and was hospitalized due to gemcitabine toxicity; otherwise, systemic therapies were well tolerated, with fatigue, anorexia, and emesis commonly reported.

Conclusion: MLPS is considered a chemotherapy and RT sensitive sarcoma subtype. In this cohort of pts age ≥70 yrs with MLPS, the majority received surgery with perioperative radiation therapy. Few pts received perioperative chemotherapy for localized high grade MLPS, precluding meaningful analysis. Pts who received systemic therapy for recurrent disease tolerated treatment well, and systemic therapy should be considered for older pts with advanced disease.