Siontis, Brittany

Abstract Background: Solitary fibrous tumors (SFT) make up less than 5% of sarcomas. The Demicco model stratifies risk of metastasis based on age, tumor size, mitotic count, and necrosis. Patients (pts) with relapsed disease have limited options. We evaluated outcomes of systemic therapies (tx) to treat SFT. Methods: A retrospective analysis was performed of pts with intermediate-to-high risk SFT confirmed by soft tissue pathologists at a multi-site health system from 1999 – 2024. Demographics, tx, and pt outcomes were analyzed. Radiographic response was abstracted from documentation by treating provider. Results: Sixty pts had intermediate-to-high risk SFT, of which 21 pts received systemic tx. Of these, 12 were male, median age at diagnosis 62.8 years (41.0 – 82.7 yrs). Tumors originated from chest (11, 52.4%), abdomen (5, 23.8%), pelvis (4, 19.0%), and skull (1, 4.8%). All pts had surgery for primary tumor, median size 16.0 cm (7.8 – 43.0), and 14 (66.7%) had surgery at relapse. Eight pts (38.1%) had perioperative radiation therapy (RT); 12 (57.1%) had palliative RT. Five (23.8%) had ablation. Of the 21 pts, 2 (9.5%) had perioperative chemotherapy (chemo). Twenty pts (95.2%) received median 2 lines (1 – 6) of palliative systemic tx (1 pt did not pursue any). One pt had partial response on dacarbazine, otherwise best clinical response was stable disease (SD, 53.1% vascular endothelial growth factor inhibitors (VEGFi), 40% chemo) or disease progression (PD). Most pts received VEGFi: 11 pts had sunitinib (median 3.1 months, range 1.0 – 10.6 mo), 11 pts had pazopanib (4.1 mo, 0.1 – 38.7), and 10 pts had temozolomide/bevacizumab (5.6 mo, 1.0 – 15.8). VEGFi was dose reduced or held in 59.4% . Discontinuation due to toxicity occurred in 34.4% of pts treated with VEGFi vs 26.7% of pts treated with chemo. Five pts received liposomal doxorubicin (median 4.8 mo, range 3.5 – 11.3). Four pts had doxorubicin with dacarbazine, ifosfamide or olaratumab (2.8 mo, 0.7 – 8.5). Two pts received dacarbazine (1.9 and 9.6 mo, respectively), and 2 pts received gemcitabine/docetaxel (0.9 and 4 mo). Eribulin and trabectedin (1 pt, respectively) were used for less than 1 mo. Tx was held or dose reduced for 1 pt on doxorubicin/dacarbazine and 1 pt on gemcitabine/docetaxel. Three pts had immunotherapy (IO, 2 pts pembrolizumab, 1 pt nivolumab/ipilimumab) and stopped for PD (2 pts) or toxicity (1 pt) after 2 mo or less. Two pts participated in clinical trials. Median time from primary surgery to relapse was 2.0 yrs (0.0 – 12.3). Sixteen pts died (76.2%), 14 from SFT. Median time from relapse to death or last contact was 4.1 yrs (0.5 – 14.7). Median overall survival from diagnosis to death/last contact was 6.6 yrs (0.6 – 27.0). Conclusion: Perioperative chemo was rarely used to treat intermediate-to-high risk SFT. For relapse, VEGFi use was more common than chemo, with more pts achieving SD and receiving longer duration of tx. VEGFi had greater toxicity and subsequent discontinuation. No benefit was observed in few pts who received IO. Clinical trial participation was uncommon. Citation Format: Miranda Lin, Brittany Siontis, Steven Robinson, Scott Okuno, Thanh Ho. Systemic Therapy and Outcomes in Patients with Intermediate or High-Risk Solitary Fibrous Tumor [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Breaking Barriers in the Fight against Rare Cancers; 2026 Jul 18-20; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(14_Suppl):Abstract nr B054.

Aims Limited data exist on atypical lipomatous tumour (ALT)/well‐differentiated liposarcoma (WDL) and de‐differentiated liposarcoma (DDLPS) in children and young adults. Methods and results Cases of ALT/WDL/DDLPS arising in patients aged ≤ 40 years were collected from multiple institutional and consultation archives. A total of 116 cases of ALT/WDL (75) and DDLPS (41) were identified, representing fewer than 5% of these tumours seen at our institutions during this time‐period. The patients (59 male/57 female) ranged in age from 8 to 40 years. Sites included deep central (abdomen/retroperitoneum/pelvis/groin) ( n = 60), extremity ( n = 42), trunk ( n = 5), head/neck ( n = 8) and mediastinum ( n = 1). De‐differentiated patterns included: high‐grade pleomorphic sarcoma, myxofibrosarcoma‐like, heterologous rhabdomyoblastic differentiation, low‐grade spindle cell sarcoma and homologous lipoblastic differentiation. Forty‐one patients experienced a local recurrence and 11 patients with DDLPS developed metastasis. ALT arising in the extremities had lower recurrence rates than deep central WDL (5‐year recurrence‐free survival 88.9% versus 59.0%; P = 0.002), while patients with deep central DDLPS experienced significantly more adverse events compared to WDL at this site (5‐year event‐free survival 11.9% versus 59.0%) ( P < 0.0001). Seven (of eight) head/neck tumours had follow‐up available; five recurred, and one patient (DDLPS) with recurrence also experienced a metastasis. The single mediastinal tumour (DDLPS) recurred and metastasised. Conclusion ALT/WDL and DDLPS occurring in patients aged ≤ 40 years is rare, but exhibits similar morphological features to its counterparts in older adults, including potential for heterologous and homologous de‐differentiation in the latter. Although case numbers are limited, tumours arising in the head and neck exhibit high rates of adverse events, suggesting that classification as WDL rather than ALT is more appropriate.

Despite knowledge that EGDT improves outcomes in septic patients, staff education on EGDT and compliance with the CPOE order set has been variable. Based on results of a resident survey to identify barriers to decrease severe sepsis/septic shock mortality in the medical intensive care unit (MICU), multifaceted interventions such as educational interventions to improve awareness to the importance of early goal-directed therapy (EGDT), and the use of the Computerized Physician Order Entry (CPOE) order set, were implemented in July 2013. CPOE order set was established to improve compliance with the EGDT resuscitation bundle elements. Orders were reviewed and compared for patients admitted to the MICU with severe sepsis/septic shock in July and August 2013 (controls) and 2014 (following the intervention). Similarly, educational slide sets were used as interventions for residents before the start of their ICU rotations in July and August 2013. While CPOE order set compliance did not significantly improve (78% vs. 76%, p = 0.74), overall EGDT adherence improved from 43% to 68% ( p = 0.0295). Although there was a trend toward improved mortality, this did not reach statistical significance. This study shows that education interventions can be used to increase awareness of severe sepsis/septic shock and improve overall EGDT adherence.