S0264 Primary Intestinal Non-Hodgkin's Lymphoma: Epidemiological Comparison With Intestinal Adenocarcinoma and Clinicopathological Findings Seen over 20 Years

INTRODUCTION: Primary Intestinal Non-Hodgkin’s Lymphoma (PI-NHL) is a rare cause of intestinal malignancy accounting for 1 - 4% of total cases. Because of low incidence, only a few case series have been published. Here we are presenting 74 PI-NHL seen over 20 years in a large university based-Hospital. METHODS: In an IRB-approved retrospective analysis, we collected data for PI-NHL (74 Patients) out of all intestinal cancers (6094 Patients) reported over a 20-year period from 2000 to 2019 from the Yale tumor registry. Variables were divided as early age of onset (≤50 years), late age of onset (>50 years), location (small and large intestine), the staging of the tumor as early-stage (stage 1 &2), late-stage tumors (stage 3 & 4) and surgical status. The continuous variables were tested using student t-tests. Categorical variables were compared using the Chi-squared test. Survival analysis was done using a cox-proportional hazard regression model. RESULTS: PI-NHL was the third most common cancer (1.26%) of the intestinal tract after Adenocarcinoma (90.13%) and Neuroendocrine tumors (6.85%). When compared to Adenocarcinoma, the incidence was more among males than females (P-value 0.059), early age of onset for cancer was more in PI-NHL (P-value 0.039) and PI-NHL was more common in the small intestine than large intestine (P-value 0.00). In survival analysis of PI-NHL, we did not find any significant finding but a trend towards higher risk of mortality in the late stages of tumor and, also when the tumor location was in the large intestine. 16 Patients (21.62%) had a complicated presentation with obstruction (15 Patients), intussusception (5 Patients), and perforation (2 Patients). Diffuse Large B-Cell Lymphoma (39.19 %) was the most common histological type of PI-NHL. 36 patients needed surgery, with no difference in survival.Table 1.: Histological Types of 5 most common intestinal cancers seen over 20 YearsCONCLUSION: PI- NHL is a rare type of intestinal malignancy. Our study showed that its incidence was more in males and had an early age of onset when compared to intestinal adenocarcinoma. The trend towards worse prognosis was seen for the late stages of tumor and if located in the large intestine. Considering lower incidence, a larger collaborative study with a bigger patient population is needed for making a definitive conclusion.Table 2.: Comparison between intestinal adenocarcinoma and primary intestinal non-Hodgkin’s lymphoma based on the gender, age of onset, and site of the tumorFigure 1.: Multivariate Cox proportional Hazard Analysis of overall survival for patients with Primary Intestinal Non-Hodgkin's Lymphoma.