Retrospective evaluation of immune checkpoint inhibitors in soft tissue sarcoma.

Abstract

e23570 Background: Soft tissue sarcomas (STS) are rare, and metastatic disease confers a poor prognosis. There are limited treatment options for systemic disease, and standard chemotherapy is the first line for many subtypes. Given the success of ICI (immune checkpoint inhibitors) in many solid tumors, ICI has been investigated in STS as well. This retrospective observational study aimed to investigate the efficacy of ICI in STS. Methods: We queried the Global Collaborative Network, comprising 170 HealthCare Organizations, using the TriNetX research platform, a federated network of de-identified electronic medical records, for identifying patients with soft tissue sarcoma (STS) using ICD10CM as well as ICD-O codes. Population was divided into two cohorts based on receipt of ICI. Propensity score matching (1:1 greedy nearest-neighbor, caliper 0.1) was performed for age, race, gender, and comorbidities. Kaplan–Meier survival analysis and comparative statistics were performed. Using the Cox proportional hazards model, we explored the effect of covariates including sex, age at index, race, marital status, obesity, nicotine dependence, alcohol use. Results: 14,623 STS cases were identified, of which 363 received ICI. Patients who received ICI were older (61.2 ± 16.4 vs 56.1 ± 19.2 years, p< 0.001), predominantly whites (75% vs 50%, p < 0.001); no significant difference in gender (males: 54% vs 49%, p = 0.0785). Prior to PSM, median follow up period was 358.5 days in ICI group and 846 days in non-ICI group. Survival probability at the end of time window was lower in ICI group (10.57% vs 22.56%, p < 0.001). After PSM, the group which received ICI had lower survival probability (11.26% vs 29.31%, p < 0.001), with median OS of 520 days in ICI group compared to 3161 days in non-ICI group. On reviewing the cox proportional hazard models, it was seen that nicotine dependance (HR 1.266 (1.096, 1.462), p = 0.0013), being male (HR 2.977 (2.589, 3.423), p < 0.001), or older age at index (HR 1.148 (1.076, 1.224), p < 0.001) increased the risk of death, while being married (HR 0.877 (0.815, 0.945), p = 0.0005)) decreased the risk of death. Conclusions: Our study aids in providing real-world data regarding the use of ICI in STS. In literature, we have seen no significant difference between ICI and SOC with OS ranging from 6.1 - 17 months with ICI. Even though our study did not show any survival benefit compared to non-ICI cohort, the median OS of ~17 months in ICI group is equivalent to current literature. STS are heterogenous disease, and further studies are required to determine which histologic subtype would benefit most from ICI.