(P 141) TREATMENT VARIABILITY IN SURGICAL MANAGEMENT OF PULMONARY OLIGOMETASTATIC SOFT TISSUE SARCOMA

Objective: Soft tissue sarcomas (STS) are rare cancers with poor prognosis requiring multidisciplinary management for both localized and metastatic disease. Prior studies have suggested variability in treatment of primary sarcoma, and metastasectomy has been shown to be associated with improved overall survival. Vulnerable populations are associated with poorer access to specialized teams, and in this study, we hypothesize that similar variability exists in the treatment of oligometastatic STS, particularly with pulmonary involvement.

Methods: The National Cancer Database was queried for patients diagnosed with soft tissue sarcoma oligometastastic to the lung between 2004 and 2020. Patient and facility level demographic data, location of primary STS site, grade, management including chemotherapy, immunotherapy, radiation, metastasectomy, as well as patient outcomes and survival were evaluated. All patients had local primary tumor control (surgical or local destruction). Group comparisons were performed by Chi-Squared and Kruskal-Wallis tests and a multivariable logistical regression model was used to assess for adjusted between-group differences in metastasectomy rate and 90-day survival.

Results: Of 689 patients with STS oligometastatic to the lung, 137 (20%) underwent metastasectomy. A majority of patients were privately insured (44%), followed by Medicare (38%), Medicaid (12%), other government insurance (1.5%), and uninsured (3.8%). Most patients (60%) were treated at an academic program, followed by comprehensive community cancer programs (20%), integrated network cancer programs (17%) and community cancer programs (3%).

No differences in metastasectomy rates were noted in patient sex, age, ethnicity, education level, income level, Charlson-Deyo score, Commission on Cancer (Coc)-facility type, urban versus rural, or great circle distance (Table 1). However, a difference in metastasectomy rate was noted among different races with 20% of Caucasians, and 13% of Black patients undergoing metastasectomy, which was significant after logistical regression on multivariable analysis (odds ratio [OR] 0.57, p=0.03). Predictors of metastasectomy included type of insurance; private 26%, medicaid 17%, medicare 15%, and uninsured 12% undergoing metastasectomy (p=0.003), however after multivariable analysis the difference was not significant. Poorly differentiated tumors were less likely to undergo metastasectomy (OR 0.27; p=0.008 after multivariable analysis). There were no differences in metastasectomy rates based on radiation, chemotherapy, or immunotherapy treatment. Significantly lower 90-day mortality was seen in patients who underwent metastasectomy (OR 0.26, p=0.004) as well as those who underwent systemic chemotherapy with or without metastasectomy (OR 0.26, p< 0.001) even after controlling for demographic factors and comorbidities (Table 2).

Conclusion: Only 20% of patients with STS oligometastatic to the lung underwent surgical resection. Lower metastasectomy rates were seen among Black patients and those with poorly differentiated tumors. Patients that did not undergo metastasectomy had significantly higher 90-day mortality. These findings highlight the need to address variability in treatment and improve access to quality multi-disciplinary care for all patients with pulmonary oligometastatic STS.