PROGNOSTIC FACTORS FOR SURGICAL RESECTION OF LEIOMYOSARCOMA LIVER METASTASIS | Poster Board #1093

Background: Sarcomas are rare mesenchymal tumors with a propensity for hematogenous metastasis, leading to liver metastasis. Advancements in liver surgery have led to increased resection of sarcomatous liver metastasis as discussed in several studies. However, said studies are limited by small cohorts and/or poor distinction of pathological sarcoma subtypes. Studies properly distinguishing subtypes contain mostly gastrointestinal stromal tumor (GIST) patients, with fewer leiomyosarcoma patients. The purpose of this study is to investigate the role of surgical intervention in a sizeable cohort of patients with leiomyosarcoma liver metastases (LLM).

Methods: We retrospectively analyzed patients who underwent hepatic resection for LLM from 1999 – 2020 at a single center. Demographic, histopathological, and survival data were analyzed.

Results: 54 patients were included (10 male, 44 female) with a median age of 62.5 years. 45 patients (83%) had an R0 resection margin of the primary tumor. The median interval between diagnosis of leiomyosarcoma and LLM was 19 months, with synchronous presentation (< 6mos) in 13 patients (24%). The median size of the largest LLM was 3.0 cm, although only 24 patients (45%) had multiple LLM. 30 patients (56%) received neoadjuvant chemotherapy prior to LLM resection. 17 patients (32%) underwent major hepatectomy, and 11 (20%) required radiofrequency ablation (RFA). Median overall survival (OS) following LLM resection was 62 months. Increased OS (all p ≤ 0.035) was seen in patients with R0 resection of the primary tumor (69 vs. 38mos), diagnosis of LLM ≥ 12mos after resection of primary tumor (69 vs. 34 months), largest LLM < 5cm (n = 42; 69 vs. 25mos), and those NOT requiring RFA (69 vs. 31mos). Amongst patients who received neoadjuvant chemotherapy, increased OS was seen in those who responded (n = 17) compared to those with stable (n=8) or progressive (n=5) disease (64, 34, 55 months respectively, p = 0.029). On multivariate analysis, R0 primary resection margin was the only prognostic factor significantly associated with increased OS (HR = 0.307, p = 0.035) while lack of RFA was borderline significant (HR = 0.144, p = 0.103). 50 (93%) patients recurred, with a median recurrence free survival (RFS) of 10mos after LLM resection. The 9 patients with liver AND multiorgan recurrence had significantly worse OS (34mos; p = 0.008) compared with lung only (n = 13; OS = 68mos), liver only (n = 17; 74mos), and multiorgan excluding liver (n = 11; 69mos) recurrence.

Conclusion: Patients with R0 margin after resection of primary leiomyosarcoma should be considered for resection of LLM. Similar to previous reports, requiring RFA, poor response to neoadjuvant chemotherapy, and LLM within 12mos of primary resection was associated with decreased OS. Of patients who recur, those with liver AND multiorgan recurrence have markedly worse OS.