E151: Variations in Stage IV Gastric Cancer Treatment by Facility Type

Metastatic gastric cancer has a dismal prognosis with a median survival of less than 12 months.  New treatment paradigms, including the use of immunotherapy, have shown an improvement in overall survival (OS) in the setting of randomized clinical trials. Consequently, the combination of immunotherapy and chemotherapy is now first-line treatment for metastatic gastric cancer patients. The purpose of our study is to examine early adoption of immunotherapy as treatment in metastatic gastric cancer across various facilities that treat stage IV gastric cancer patients and to determine if a similar survival benefit is observed.

Methods:

This was a retrospective study using the National Cancer Database from 2004 -2020018. All patients over age 40 with stage IV gastric cancer and available information about receipt of chemotherapy, radiation, and immunotherapy were included in the study. The independent variables of interest were facility type (Community Cancer Program, Comprehensive Community Cancer Program, Academic/Research Program, Integrated Network Cancer Program).  The proportion of patients who received immunotherapy was assessed across facilities over the study period. Overall survival was compared between patients who received immunotherapy and those who did not using Kaplan-Meier estimates and multivariable Cox proportional hazards regression.

Results: The rate of immunotherapy used increased for all facility types, but the largest uptake was seen at academic/research programs.   In multivariable analysis adjusted for age, gender, race, rurality, comorbidity, insurance status, facility type, region, histology, grade, tumor location, treatment with chemotherapy, and treatment with immunotherapy; treatment with immunotherapy was associated with an improved overall survival.  Despite immunotherapy uptake across all facility types treating metastatic gastric cancer patients, treatment at academic research/programs resulted in improved overall survival compared to the community cancer programs. 

Conclusions: In this retrospective cohort study, the use of immunotherapy among metastatic gastric cancer patients significantly increased over the study period. Receipt of immunotherapy and receipt of care at academic facilities were associated with an increased overall survival. As the uptake of immunotherapy increases for metastatic gastric patients nationally, an understanding of how this novel therapy is
allocated nationally is prudent.