# Association of Medicaid expansion with colon cancer care: treatment patterns and survival in non-metastatic cases from state registry-claims data

## TL;DR

This study examines how Medicaid expansion in Ohio affected colon cancer treatment and survival, finding improved survival for newly eligible patients but no significant changes in treatment patterns.

## Contribution

The study provides new insights into how Medicaid expansion specifically impacts survival outcomes for colon cancer patients, independent of treatment patterns.

## Key findings

- Medicaid expansion was associated with significantly improved survival among newly eligible patients (HR 0.49).
- Emergently enrolled patients were more likely to receive standard treatment (RR 1.14).
- No significant changes in treatment likelihood or timely initiation were observed post-expansion.

## Abstract

Despite growing research on Medicaid expansion’s impact on cancer outcomes, there remains a critical need for a more nuanced understanding of how expansion affects cancer care and survival. This study assesses whether Medicaid expansion was associated with improved receipt of standard treatment, timely treatment initiation, and overall survival among colon cancer patients, while examining the specific factors influencing these outcomes.

Using Ohio’s state cancer registry linked with Medicaid records, we analyzed 688 Medicaid-enrolled patients with non-metastatic colon cancer diagnosed between May 2011 and December 2017. We employed multivariable Poisson and Cox proportional hazard regression analyses to evaluate the impact of Medicaid expansion on treatment and survival outcomes, controlling for individual- and area-level factors.

We observed no significant changes in the likelihood of receipt of standard treatment or timely treatment initiation post-expansion vs. pre-expansion, and no significant differences in these outcomes by Medicaid eligibility criteria post-expansion. However, we observed significantly improved survival (hazard ratio, HR 0.49 [0.28, 0.88]) among patients who became newly eligible for Medicaid under the ACA vs. pre-expansion. Patients enrolled emergently (shortly after/upon diagnosis) were more likely to receive standard treatment (risk ratio, RR 1.14 [1.02, 1.27]).

Our findings provide nuanced insights into Medicaid expansion’s impact on colon cancer care, showing that while expansion did not affect treatment measures, it improved survival among newly eligible patients. Higher standard treatment likelihood among emergently enrolled patients suggests complex post-expansion care dynamics. Further research should investigate mechanisms underlying improved survival and develop interventions to enhance treatment quality alongside observed survival benefits.

The online version contains supplementary material available at 10.1007/s10552-025-01983-8.