Impact of Medicaid Expansion on Stage at Diagnosis for US Adults with Pancreatic Cancer: a Population-Based Study

Introduction: We evaluated whether Medicaid expansion is associated with earlier stage at diagnosis for pancreatic cancer taking into account key demographic, clinical, and geographic factors.

Methods: We obtained Surveillance, Epidemiology, and End-Results (SEER-18) data on individuals diagnosed with pancreatic cancer from 2007 to 2016 (< 65 years of age). We defined non-metastatic as either local or regional disease (vs. metastatic disease). To estimate the association of Medicaid expansion with pancreatic cancer stage at diagnosis, we used a difference-in-differences model, at the individual level, comparing those from early-adopting states in 2014 to non-early-adopting states. We utilized cluster-robust standard errors and explored the role of demographic factors (race, sex, insurance at diagnosis), clinical indicator (disease in the head of the pancreas), and county characteristics (Urban Influence Code, Social Deprivation Index).

Results: In the univariable setting, the probability of non-metastatic disease at diagnosis increased by 3.9 percentage points (ppt) for those from Medicaid expansion states post-expansion (n = 36,609). After adjustment for covariates, the ppt was attenuated to 2.7. Of particular note, we observed evidence of interactions with sex and race. The beneficial effect was less pronounced for men (increase in the probability of non-metastatic stage at diagnosis by 2.1ppt) than women (3.6ppt) and non-existent for blacks (- 3.1ppt) compared to whites (4.9ppt) and other races (4.8ppt).

Conclusion: Medicaid expansion is associated with increased probability of non-metastatic stage at diagnosis for pancreatic cancer; however, this beneficial effect is not uniform across sex and race. This underscores the need to investigate the impact of policy and implementation strategies on pancreatic cancer survival disparities.