(P 300) FEATURES AND OUTCOMES OF PATIENTS WITH GASTROINTESTINAL LEIYOMYOSARCOMA

Objective: Gastrointestinal (GI) leiomyosarcomas (LMS) are aggressive spindle cell neoplasms from GI smooth muscle. The incidence is low and limited to a few case series. This study evaluated treatment (tx) and outcomes of patients (pts) with GI LMS.

Methods: We performed a chart review for pts aged 18 and above with GI LMS from 1/1/00 to 12/31/24 treated at Mayo Clinic.

Results: Twenty-nine pts had GI LMS. Ten (34.5%) were female, median age was 67 years (range 35 – 81 yrs). Twenty-one (72.4%) pts had symptoms: GI bleed (8/29, 27.6%), abdominal pain (8/29, 27.6%), and odynophagia (3/29, 10.3%). Most common site was small intestine (11/29, 37.9%) followed by stomach (8/29, 27.6%), colorectal (5/29,17.2%), and esophagus (5/29, 17.2%). Median tumor size was 5.8 cm (0.7 – 25 cm).

Of pts with localized disease (n=25), 24 had surgery (sx). One pt had neoadjuvant chemotherapy (chemo); 1 had neoadjuvant radiation therapy (RT). One pt received adjuvant chemo. One pt with esophageal LMS had definitive RT with stable scans 6 yrs later.

Seven (28%) pts relapsed, median relapse-free survival was 7 months (range 5 – 20). Of these, 1 (14.2%) had local and 6 (85.7%) had distant recurrence, most commonly to liver. Six (85.7%) pts received tx for recurrence, one pursued hospice. Three pts received chemo; 2 pts had sx, and 1 pt had RT followed by gastrectomy. Three pts died from recurrent LMS. Median overall survival (OS) for pts with localized disease was 40 months (range 3 – 290).

Four (13.8%) of 29 pts had metastatic disease at diagnosis (Table 1). Of these, 3 had chemo, 1 had RT, and 1 had sx. Median OS was 20 months (range 10 – 30).

Conclusion: In this cohort of GI LMS, pts with localized disease had favorable outcomes, and few relapsed within the first two years of surgery. Perioperative chemo or RT was uncommon. Outcomes for localized LMS originating in GI tract appear more favorable compared to other sites.

Table 1: Pts with metastasis at dx