407PFocal treatments for metastatic soft tissue sarcoma (mSTS) is associated with improved overall survival

Abstract Background The benefit of focal treatments, including surgery and radiotherapy, in mSTS patients has not been clear, especially for mSTS patients who had received systemic treatments. Methods Medical records of mSTS patients treated at National Taiwan University Hospital from 2011 to 2017 were collected. The focal tx collected included surgery (either for the primary or metastatic tumors) and radiation therapy (RT). The analysis was limited to patients who had received at least one-line of systemic treatment. Overall survival (OS) was measured from the time of mSTS diagnosis to the date of death or the last follow-up, whichever is later. Results A total of 199 patients, 78 (39%) de novo and 121 (61%) recurrent, mSTS were identified. The median age was 55 (range 20-89) and male to female ratio was 0.86. The most common histologies are leiomyosarcoma (16.5%), liposarcoma (15.6%), and sarcoma NOS (15.6%). Of them, 72 (36.2%) and 48 (24.1%) patients received surgery and RT, respectively. Metastatic STS patients who had received surgical treatment had a significantly better OS as compared with those who did not (median OS 21.9 vs 16.5 months, p = 0.0296). There was a trend that the OS benefit of surgery was mostly in patients with recurrence but not de novo mSTS (p for interaction = 0.08). The type of surgery (primary vs metastatic vs primary + metastatic) did not significantly affect OS (p = 0.608). Patients who received RT had a numerically better survival (median OS 24.4 vs 16.9 months, p = 0.12). In the multivariate Cox model, the OS benefit of surgery remained significant (Table). Table . 407P Adjusted hazard ratio of OS for mSTS patients who received palliative systemic treatment HR 95% CI p-value Female vs male 1.22 (0.85, 1.76) 0.2852 Age 1.01 (1.00, 1.02) 0.0830 Histology Other 1 0.0436 Leiomyosarcoma + Liposarcoma 0.65 (0.43, 0.99) Anthracycline 1.63 (1.12, 2.37) 0.0109 Focal treatment 0.0731 No focal treatment 1 RT 0.62 (0.36, 1.08) 0.0923 Surgery 0.63 (0.40, 0.99) 0.0452 RT + Surgery 0.55 (0.30, 1.00) 0.0502 Conclusions Patients with mSTS had improved OS with focal treatments, especially with surgery. A multi-disciplinary team approach to include the surgeons and radiation oncologists to discuss the optimal treatment of mSTS patients should be advocated. Legal entity responsible for the study The authors. Funding Eli Lilly and Company. Disclosure All authors have declared no conflicts of interest.