Epidemiology and Determinants of Survival for Primary Intestinal Non-Hodgkin’s Lymphoma – A Population Based Study

Introduction Gastrointestinal tract is the most common site of extra nodal non-Hodgkin’s lymphoma (EN-NHL). Most of the published data have been on gastric NHL with limited studies on primary intestinal - Non-Hodgkin’s Lymphoma (PI-NHL) considering rare incidence. We performed epidemiological and survival analysis for PI-NHL from the Surveillance, Epidemiology, and End Results (SEER) 18 database. Methods A total of 9143 PI-NHL cases of age ≥18 years were identified from the SEER 18 database for the period 2000-2015. 8568 Patients were included for survival analysis. Cause specific Survival (CSS) and overall survival analysis (OS) were done for PINHL and PI-diffuse large B-cell lymphoma (PI-DLBCL) using gender, age of onset, treatment, histology, stage, and Year of diagnosis. Survival analysis was done by using cox-proportional hazard model and Kaplan Meier plot with log-rank test. Results The percentage of PI-NHL of all the intestinal cancers and extra nodal non-Hodgkin’s lymphoma were 1.35 %, and 10.52%, respectively. The age-adjusted incidence was 0.9145/100,000 population for the study population. PI-NHL was more common among patients aged≥60 Years, male and non-Hispanics whites. Majority of patients were diagnosed at stage 1 and 2 (74%), and DLBCL (44.8%) was the most common histology. In OS analysis, Significant increased risk of mortality was seen with T-cell NHLs vs. DLBCL (HR – 2.56), patients aged ≥60 vs <60 Years (HR – 2.87), stage 4 vs Stage 1 (HR – 1.93), male vs. female (HR- 1.17), with best outcome seen in patient treated with combination of chemotherapy and surgery vs. none (HR – 0.45). Similar results were seen in CSS and for primary intestinal DLBCL as well. Significant improvement in outcomes was observed for PI-DLBCL patients receiving chemotherapy with/without surgery. Conclusion Findings: from our large, population-based study reveal PI-NHL is a rare type of intestinal malignancy with significant difference in survival based on histological and epidemiological characteristics.