9025 Background: Many patients diagnosed with advanced non-small cell lung cancer (NSCLC) will develop intracranial metastasis, contributing significantly to morbidity and mortality. Immunotherapy (IMT) has emerged as the standard of care in select cases of metastatic NSCLC, though data investigating the survival impact of IMT and radiation (XRT) in these patients is limited. To characterize the survival impact of intracranial XRT and IMT in NSCLC patients with brain metastasis, we analyzed the National Cancer Database (NCDB). Methods: We queried the NCDB for patients with metastatic NSCLC having brain metastasis receiving intracranial XRT ± IMT. Univariable and multivariable analyses identified characteristics predictive of overall survival. Cox proportional hazard ratios with propensity matching mitigated indication bias between the two arms. Results: 13,998 NSCLC patients who received IMT (n = 545) or did not receive IMT (n = 13,545) were eligible for analysis. Univariable analysis demonstrated a median overall survival of 13.1 months (95% CI: 11.8-15.0) vs. 9.7 months (95% CI: 9.5-9.9) (p < 0.0001) and 3-year overall survival of 17% vs. 12% [p < 0.0001; HR: 0.77 (0.71-0.84)] in patients receiving and not receiving IMT respectively. Patients with N3 disease and those diagnosed between 2012 and 2014 were more likely to have received IMT. Receipt of IMT remained an independent predictor of increased survival on propensity score matched multivariable comparison (p = 0.0002). Conclusions: Receipt of IMT was an independent predictor of increased overall survival in patients with NSCLC having intracranial metastasis. Randomized, prospective studies are needed to further validate these findings. [Table: see text]

e21213 Background: Lung cancer is the leading cause of death in males and females in the United States. Approximately 85% of all cases are classified as non-small cell lung cancer (NSCLC) with majority diagnosed at an advanced stage. Unfortunately, response to traditional chemotherapy (ChT) has been poor with a five-year survival rate of 6% in metastatic NSCLC. Immune checkpoint inhibitors (ICI) have changed the therapeutic landscape for advanced NSCLC and are being utilized alone or in combination with ChT as the standard first-line therapy. With widespread use of ICIs, immune-related adverse events (irAE) are commonly seen and in some studies their occurrence correlates with improved outcomes. The aim of our study was to evaluate whether development of irAEs has an impact on survival in NSCLC. Methods: We performed a retrospective analysis on stage IV NSCLC patients treated with ChT, ChT plus ICI, or ICI monotherapy from December 2016 to December 2019. Univariable and multivariable analyses identified characteristics predictive of progression-free survival (PFS) and overall survival (OS). OS was calculated using Kaplan Meier curves. Log-rank statistics were used to assess statistical significance between groups. Multivariable logistic regression was performed to identify predictors of survival. Results: 193 patients were evaluated out of which 92 (47.2%) received ChT plus pembrolizumab, 69 (35.4%) received pembrolizumab alone and 32 (16.4%) received ChT alone. 130 patients were found to have no irAEs compared to 57 patients who were noted to have any grade of irAE. The median PFS was 17.4 months (irAE group) vs. 8.5 months (non-irAE group) with hazard ratio (HR) of 0.58 (95% CI: 0.41 to 0.80, p = 0.001). The median OS was 29.4 months (irAE group) vs. 14.4 months (non-irAE group) with HR of 0.56 (95% CI: 0.39 to 0.82, p = 0.0026). A multivariate analysis was performed for age, gender, ECOG performance status, insurance status, BMI, PDL1 status and smoking history, amongst other variables. Worse survival outcomes were noted with an ECOG performance status ≥ 2, no history of smoking, and involvement of palliative care. Multivariable logistic regression analysis showed that PDL-1 expression > 50% was the only predictor of developing an irAE. Of note, receipt of ChT in combination with pembrolizumab compared to pembrolizumab alone did not predict for development of irAE. Conclusions: Development of irAEs was associated with doubling of PFS and OS, regardless of whether the ICI was administered alone or in combination with ChT. The differences were statistically significant regardless of age, gender, race, BMI, insurance status or performance status. Our study highlights the correlation between development of irAEs and improved survival outcomes in advanced NSCLC patients treated with ICIs.

Background Pheochromocytomas are a subset of paragangliomas, which are a rare group of neural crest cell-derived tumors. Malignant cases of both pheochromocytomas and paragangliomas are even rarer, and currently there is no standard of care. This case report details the use of off-label immunotherapy and its efficacy in the management of the aforementioned tumor. Case presentation Herein is presented a case of a 60-year-old Caucasian female with a rare malignant pheochromocytoma. The tumor was determined to be unresectable because of involvement of surrounding organs. Radiation therapy was also not a viable option because of concerns over appreciable toxicity in relation to mass size. As there is no standard of care for malignant cases, the patient was started on chemotherapeutic agents but was soon shown to be intolerant to this treatment. As she was ineligible for several clinical trials, the patient was started on the off-label immunotherapeutic agents nivolumab and ipilimumab. Immunotherapy use resulted in decreased tumor size, improved quality of life, and reconsideration for radiation therapy. Conclusions The use of immunotherapy in pheochromocytoma in this patient clearly demonstrated substantial benefit, as she was able to be reconsidered for radiation therapy. Not only has the patient been tolerant of this treatment, but she has exhibited progression-free survival of over 20 months. As there is no current standard treatment for malignant pheochromocytomas, the success of its use in this patient lends support to the ongoing clinical trials regarding the use of immunotherapy in rare tumors, including pheochromocytomas.

e21506 Background: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer with a broad spectrum of targeted therapies already available or in clinical trials. Among the NSCLC patients, 23% to 25% harbor a mutation in a gene associated with approved or emerging targeted therapy. These therapies have changed the therapeutic landscape of NSCLC with significantly improved clinical outcomes in advanced metastatic NSCLC patients. It is imperative to test for these gene alterations in order to identify patients who could potentially benefit from these efficacious targeted therapies and to avoid therapies unlikely to provide clinical benefit. A major limitation in obtaining molecular testing occurs when minimally invasive techniques are used to obtain tissue sample resulting in insufficient yield for testing. In such cases, the utilization of circulating tumor DNA (ctDNA), commonly known as liquid biopsy, has proven very beneficial. In a study utilizing ctDNA, increased detection rates were found when using ctDNA in addition to tissue testing and a > 98.2% concordance rate was found. We report results of 40 NSCLC patients from our institute who had liquid biopsy with or without tissue profiling done. Methods: We molecularly profiled 40 newly diagnosed advanced NSCLC patients using both tissue and liquid biopsies. Tissue was assayed using the John Hopkins university molecular panel and liquid biopsies were performed by Biocept. Results: 14 out of 40 (35%) patients had insufficient or no tissue for molecular testing. Concordant results were found in 17 out of the 26 (65.4%) patients who had both tissue and liquid molecular testing done. Liquid Biopsy detected additional mutations in 5 (19.2%) patients which were not picked up on tissue and led to change in management in 4 patients. 12 out of 40 (30%) patients had repeat liquid biopsies done at progression of disease with new mutations detected on 4 patients revealing resistance to current treatment and change in treatment. Conclusions: Liquid Biopsy reveals high concordance rates with tissue genotyping and increases rate of detection of targetable mutations in NSCLC. It offers a safe and effective alternative when additional tissue is needed to identify genetic mutations.

e16258 Background: Cytotoxic chemotherapy remains the standard of care in the treatment of pancreatic ductal adenocarcinoma (PDAC). There is more excitement in the last few years regarding the use of neoadjuvant chemotherapy even when the disease is resectable. In this analysis, we sought to study the different regimens used in our institutions, in regards to setting and toxicity. Methods: We retrospectively reviewed all patients diagnosed with pancreatic adenocarcinoma at Allegheny General Hospital between 2009-2020. Data was extracted from electronic medical records and de-identified. Institutional Review Board approval was obtained. Descriptive analysis was undertaken and multivariate analysis was performed to compare differences in the prevalence of toxicity across the regimens and demographics using Stata version 16. The primary outcome was the rate of toxicity that prompted dose adjustment, stratified by the setting chemotherapy was administered (neoadjuvant, adjuvant, or palliative). Results: Of the 121 patients studied, 88 patients received chemotherapy. Median age was 69 years. 66 patients (55%) were females. 40 patients suffered from adverse effects requiring a dose adjustment. 85% of the adverse effects occurred in Caucasians. 15 out of 37 patients (42.9%) who received Folfirinox, 15 out of 31 patients (48.4%) who received gemcitabine and nab-paclitaxel, 6 out of 10 patients (60.0%) who received gemcitabine and capecitabine, 3 out of 4 patients (75.0%) who received gemcitabine monotherapy required dose adjustment (table). Folfirinox and gemcitabine with nab-paclitaxel were statistically compared and found to be not significant (p-value=0.12). No significant impacts of race, gender, or age were noted in a multivariate model. Conclusions: Approximately 42% of patients receiving chemotherapy suffered from toxicities that required dose adjustments. We found a trend toward more use of neoadjuvant chemotherapy in resectable PDAC with a similar toxicity rate compared with other settings.[Table: see text]