483 Background: Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with no standard second line chemotherapies. We conducted a retrospective study with the primary aim to examine the effect of second line chemotherapy with nab-paclitaxel-based regimen on the overall survival (OS) and progression-free survival (PFS) of locally advanced and metastatic PDAC patients. Methods: Indiana University Simon Cancer Center (IUSCC) Cancer Registry was used to identify patients with locally advanced or metastatic PDAC between 2009 and 2015. Only patients who received second line chemotherapies were included in the study. These patients were divided in to two groups: a) nab-paclitaxel-based treatment and, b) non-nab-paclitaxel-based treatment. Demographic (age, race, gender, year of diagnosis, family history, comorbidity), clinical (histology, CA 19-9, bilirubin, tumor location, performance status, metastatic sites, chemotherapy, surgery or radiation) and outcome (OS, PFS) characteristics were obtained. OS and PFS were estimate by using Kaplan-Meier method and 95% CI. Cox proportional-hazard model was used for multivariate analysis. Results: Forty-seven (39%) and seventy-three (61%) patients received nab-paclitaxel-based and non-nab-paclitaxel-based second line chemotherapy, respectively. In the univariate analyses, nab-paclitaxel-based treatment was only associated with younger age (60.4 vs. 64 years; P = 0.02). The median PFS was 2.8 and 2.1 months (HR 0.62; 95% CI 0.38-1.02; P = 0.06), and the median OS was 7.5 and 4.7 months (HR 0.67; 95% CI 0.45-1.00; P = 0.05) in patients who received nab-paclitaxel based second line treatment versus not, respectively. Multivariate analyses adjusted for age showed a significantly improved PFS (adjusted HR 0.60, 95% CI 0.36-0.98; P = 0.04) and a suggestion of improved OS (adjusted HR 0.67; 95% CI 0.44-1.01, P = 0.05) in the nab-paclitaxel based second line treatment group versus not, respectively. Conclusions: In a single institution retrospective study, we report significant improvement in the PFS and a suggestion of improvement in the OS with nab-paclitaxel based treatment as compared with non-nab-paclitaxel based treatment in the second line setting.

OS (7.5 vs. 4.7 months; HR=0.67, p=0.05). Multivariate analyses adjusted for age showed a significantly improved PFS (adjusted HR=0.60, p=0.04) and a suggestion of improved OS (adjusted HR=0.67, p=0.05) Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer and is the fourth leading cause of cancer-related mortality in the United States (US) (1). In 2017 alone, 53,670 cases of PDAC are expected, resulting in approximately 43,090 deaths in the US (2). The median overall survival (OS) of patients with PDAC is 20% at 1 year and 8% at 5 years (3). Despite recent progress, there is a clear need to improve systemic treatments for PDAC. Recently, nab-paclitaxel (NP) in combination with gemcitabine (GA) was shown to lead to a clinically meaningful and significant improvement in the median OS and median progression-free survival (PFS) when compared with gemcitabine alone (4). This has led to the approval of GA as a first-line treatment for PDAC similar to FOLFIRINOX (folinic acid, 5-fluorouracil, irinotecan and oxaliplatin), the only other first-line treatment for patients with metastatic PDAC (5).In clinical practice, many patients may receive FOLFIRINOX as first-line treatment and GA as the secondline treatment especially in the US (6). Many factors influence the decision to select between FOLFIRINOX and GA including age, performance status, associated comorbidities and potential toxicity (7). FOLFIRINOX is often chosen for patients with good performance status, age ≤75 years and lack of or controlled comorbidities (7,8). Usually in this scenario, GA is the preferred second-line treatment after progression on FOLFIRINOX in the absence of prospective data. Alternatively, 5-fluorouracil-based second-line therapy in combination with nanoparticle liposomal irinotecan (9) or oxaliplatin (10, 11) has shown OS benefit in second-line treatment. Interestingly, up to 50% of patients with PDAC may be eligible for second-line chemotherapy (12, 13). 5533

Introduction: MEITL is a rare and rapidly progressive extranodal T-cell lymphoma that arises from the intestinal intraepithelial T lymphocytes. Established in the 2016 WHO classification, this entity was carved out of what was previously known as type 2 enteropathy-associated T-cell lymphoma. MEITL usually affects the young-old and is not associated with celiac disease. We conducted this analysis to explore the clinicopathologic determinants of survival in this newly established T-cell entity. Methods: In order to study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 116 cases. Kaplan-Meier survival curves were constructed. Cox proportional-hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS). Results: A total of 116 patients with confirmed MEITL were identified. The median age was 59.5 years with a peak incidence between ages 56 and 68. There was a male predominance with M:F ratio of 2. The jejunum was the most commonly involved site (71%). Median OS of the whole group was 11 months. The most common presentations were abdominal pain, followed by perforation, diarrhea, and weight loss. The majority presented at stages I&II (78%). The median duration of symptoms prior to diagnosis was 4 months. Compared to no treatment, combination chemotherapy and stem cell transplant (SCT) were statistically superior with a median OS of 2, 9, and 34 months respectively (p=0.0005). Further analysis revealed that surgical resection imparted a survival advantage on its own and in conjunction with combination chemotherapy and SCT. When surgical resection was incorporated in the analysis, median OS amounted to 2, 5, 7, 11, 13, 24 months for no treatment, surgery alone, chemotherapy, surgery+chemotherapy, SCT, and surgery+SCT respectively (p=0.0015). The quality of response to treatment also seemed to impact the outcome (p=0.0005) with median OS of 6, 36, and 60 months for none/transient, PR, and CR respectively. OS was not impacted by sex, presentation with obstruction or perforation, or anatomic site involvement. While older age, weight loss, and TCRγδ seemed to negatively impact OS, they did not reach statistical significance. Conclusions: This study presents an updated clinicopathologic data from a pooled cohort of patients with MEITL. It identifies quality of response, treatment modalities as well as surgical resection as major determinants of OS in this rare disease. Disclosures No relevant conflicts of interest to declare.

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