(P 213) EXPERIENCE WITH THE USE OF TRABECTEDIN IN ADVANCED SOFT TISSUE SARCOMA IN IRELAND

Objective: Soft tissue sarcoma (STS) is comprised of 80 pathologic subtypes based on a combination of distinctive histological features. Adult-type soft tissue and visceral sarcomas are rare, with an estimated incidence of 4-5/100,000 per year in Europe. Trabectedin is licensed for advanced soft-tissue sarcoma in Europe, after failure of anthracyclines and ifosfamide, or for patients who are unable to receive these agents. Our aim of this project is to retrospectively analyse the use of trabectedin in an Irish cohort and assess its efficacy and tolerability.

Methods: All adult patients who received at least one cycle of trabectedin in the palliative setting for soft tissue sarcoma between June 2014 and June 2023 were retrospectively analysed across five Irish cancer centres. Data regarding clinicopathological characteristics, toxicity and outcomes were collected. Overall survival (OS) and progression-free survival (PFS) was recorded and assessed using Kaplan Meier method for time to event analysis.

Results: One hundred and sixteen patients were included in the overall analysis, with a median age of 57 (range, 23-82 years). The most common subtypes were leiomyosarcoma (n=46), liposarcoma (n=16), synovial sarcoma (n=12), and pleomorphic sarcoma (n=8), with a further 24 subtypes with less than five patients each. The median number of previous palliative chemotherapy regimes was 1 (range, 0-5), with 53% of patients (n=62) having received an anthracycline in the palliative setting. Patients received a median number of 3 cycles of trabectedin (range, 1-40). Median PFS and OS of the entire cohort was 2.5 months (range 0-30 months) and 7 months (range 0-67 months), respectively. This varied considerably by subtype. Patients with leiomyosarcoma or liposarcoma (abbreviated as L-type sarcoma) had a progression free survival of 3 months (range 0-67 months), compared to 2 months (range, 0-21 months) for all other subtypes (p < 0.05). For patients with toxicity data collected (n=67), 10% stopped treatment due to toxicity, 31% had an unscheduled admission and 14.9% required a dose reduction.
There were 26 patients total with a progression free survival of over six months. They had received a median of 1 line of previous systemic treatment in the palliative setting (range 0-2). They had diagnoses of soft tissue leiomyosarcoma (n=9), myxoid liposarcoma (n=8), poorly differentiated sarcoma (n=3), uterine leiomyosarcoma (n=2), and one patient each with dedifferentiated liposarcoma, solitary fibrous tumour, synovial sarcoma and sclerosing epithelioid fibrosarcoma. They received a median of 12 cycles of trabectedin with a median PFS of 13 months and OS of 38 months. Of those who had data collected regarding toxicity (n=14), five (35.7%) required a dose reduction.

Conclusion: This retrospective real-world study underlines trabectedin’s role as a well-tolerated second line treatment in advanced sarcoma. Further studies are required to identify the patients who may benefit most from trabectedin.