(P 375) FROM SAPLING TO SHADE: GROWTH OF A HIGH VOLUME ASIAN TERTIARY SARCOMA SPECIALISED CENTRE

Objective: To characterise and evaluate the change in volume of retroperitoneal sarcoma (RPS) resections in National Cancer Centre Singapore (NCCS) and Singapore General Hospital (SGH) across 3 phases of sarcoma management in 20 years (2002-2008, 2009-2017 and 2018-2022) with that of internationally recognised threshold volumes. In phase 1 (2002-2008), sarcoma management was organ-centric and undertaken by various general surgical subspecialties. Phase 2 (2009-2017) saw the emergence of surgical oncologists and phase 3 (2018-2022) heralded the establishment of the Department of Sarcoma, Peritoneal and Rare Tumours (SPRinT), the first and only sarcoma specialised surgical unit in Singapore. To compare the change in volume as sarcoma management evolved overtime in our institution with that of internationally recognised thresholds of low to high-volume sarcoma centres and determine the key factors behind the growth of our sarcoma service.

Methods: All patients who underwent RPS resections at NCCS and SGH over a 20-year period from February 2002 to October 2022 were identified and retrospectively reviewed from a prospectively maintained database. Patient, tumour and treatment characteristics were summarised for these patients in 3 different groups (group 1: 2002-2008, group 2: 2009-2017 and group 3: 2018-2022) representing 3 different phases of sarcoma care in our institution.

Results: 112 (12.5%) patients underwent RPS resection at NCCS and SGH over the 20-year period. 35 (31.3%) patients were in group 1, 61 (54.5%) patients in group 2 and 16 (14.3%) patients in group 3. Patients in all three groups were similar in patient and tumour characteristics. Group 3 patients underwent more extensive surgeries with 30 (85.8%) patients having two or more organ resections as compared to 26 (42.6%) patients in group 2 and 0 patients in group 1. Increased surgical subspecialty collaboration was observed in group 3, with 27 (77.1%) resections completed in collaboration with 1 or more subspecialty teams as compared to 11 (18.0%) cases in group 2 and 4 (25.0%) cases in group 1. Postoperatively, 30-day mortality and need for reoperation were low in all groups, however the proportion of patients with more severe postop complications (Clavien-dindo score ≥3) was greatest for group 2 (34.4%) as compared to group 3 (17.1%) and group 1 (6.3%). In terms of RPS surgical volume, phase 1 (2002-2008) saw an average of 2 resections a year which is equivalent to that of a low-volume centre by the conventional threshold of < 5 resections per year. From phase 2 (2009-2017), the advent of trained surgical oncologists saw a triple increase in RPS surgical volume averaging 6 resections a year, corresponding to that of a moderate-volume centre with a conventional threshold of 5-10 resections per year. By phase 3 (2018-2022), with the establishment of SPRinT and centralisation of sarcoma care, annual RPS surgical volume rose to 11 and 13 resections in 2020 and 2021 respectively, meeting the widely accepted threshold of >10 resections a year for a high-volume centre.

Conclusion: SGH and NCCS is a high-volume tertiary centre with long-standing experience in managing complex and diverse forms of soft tissue and visceral sarcoma such as RPS. The increase in volume of RPS resections across 20 years from that of a low-volume to moderate and eventual high-volume centre corresponds to an evolution in sarcoma management from being organ-centric to centralisation of care as recommended by international guidelines. Specialisation and centralisation of sarcoma care was also associated with an increase in extensiveness of resections undertaken, increased collaboration and reduced postoperative complications and our experience demonstrates the achievable goal of transforming a low-volume to high-volume centre for sarcoma care in a short span of 20 years through the establishment of a centralised, sarcoma-specialised surgical unit.