(P 370) DEFYING NORMS - CENTRALIZATION OF SARCOMA CARE ON AN ISLAND NATION

Objective: Current guidelines recommend that management of retroperitoneal sarcomas (RPS) be carried out in high-volume referral centers with specialized and multi-disciplinary teams. This has been shown to significantly improve both oncological and surgical outcomes. In Asia, however, there is limited data pertaining to centralization of sarcoma care. Traditional surgical units tend to be organ-centric and lack experience in the management of RPS which typically do not respect anatomical boundaries and frequently demonstrate multi-visceral involvement. The Department of Sarcoma, Peritoneal and Rare Tumors (SPRinT) was established in National Cancer Centre Singapore (NCCS) and Singapore General Hospital (SGH) as the first and only surgical oncology service in Singapore dedicated to the care of patients with peritoneal surface malignancies, soft tissue sarcomas, skin cancers and other rare tumors. With SPRinT also came the implementation of the Sarcoma Pre-Emptive Evaluation and Diagnosis (SPEED) protocol to facilitate prompt referrals of sarcomas in Singapore. This has resulted in a higher number of referrals and consequently an improved malignancy pick-up rate. This study aims to describe the early experience and outcomes of RPS treatment since the conception of SPRinT in 2019.

Methods: All patients who underwent RPS resection at SPRinT from September 2019 to October 2022 were reviewed from a prospectively maintained database. Tumor histology was reviewed by minimally two experienced pathologists and each case was discussed comprehensively at a specialized multi-disciplinary tumor board comprising surgical oncologists, medical oncologists, radiation oncologists, radiologists and pathologists. All treatment plans were guided by international evidence-based guidelines and tailored for each patient by the multi-disciplinary team. The patient, disease and treatment characteristics, as well as surgical and oncological outcomes were summarized.

Results: 42 patients were included in this study. The median age was 62 years. 22 patients (52.4%) were male and 33 (78.6%) were of Chinese ethnicity. In terms of functional status, 21 patients (50.0%) were Eastern Cooperative Oncology Group (ECOG) performance status 2 and 35 (83.8%) were American Society of Anesthesiologists (ASA) physical status class 2. 23 patients (54.8%) had dedifferentiated liposarcoma (DD-LPS) which was the most common histological subtype and 22 (52.4%) had Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) grade 3 disease. (Table 1)

9 patients (21.4%) received neoadjuvant radiotherapy while 2 (4.8%) received neoadjuvant chemotherapy. The median operative time was 190 minutes and median blood loss was 250ml. Macroscopically negative margins were achieved in 40 patients (95.2%). The most common multi-disciplinary surgical specialties involved were Vascular Surgery, Urology and Hepatopancreatobiliary Surgery in 21 (50.0%), 12 (28.6%) and 7 (16.7%) patients respectively. (Table 2)

Major complications (Clavien-Dindo 3 and above) occurred in 7 patients (16.7%) with 1 (2.4%) requiring reoperation and 1 (2.4%) mortality within 30 days. The median length of stay was 9 days, median time to ambulation was 2 days, and median time to diet was 3 days. (Table 3)

The median overall survival was 28.2 months and the 2-year overall survival was 72.8%. (Figure 1)

Conclusion: SPRinT is a dedicated specialist unit that is committed to providing state-of-the-art sarcoma care. The early experience at SPRinT has demonstrated favorable outcomes and may provide useful reference for other cancer centers aiming to become high-volume referral centers in the region. Further follow-up is needed to better evaluate long term oncological outcomes.