New Medicaid beneficiaries who were eligible thanks to the change in income requirements were 15 percent less likely to be diagnosed with metastatic cancer than they were before the act's implementation in 2014, the researchers said.
In general, this means their cancers were caught earlier, they said.
"A 15 percent reduction among this vulnerable group is a very large effect to have happened in such a short period," co-author Dr. Johnie Rose told UPI.
"This represents a meaningful improvement in a stubborn health disparity -- an improvement that will translate to lives saved," said Rose, an assistant professor at Case Western Reserve University School of Medicine's Center for Community Health Integration.
The ACA, also known as Obamacare, expanded Medicaid coverage for most adults in the United States with incomes below 138 percent of the federal poverty level in states that opted to expand coverage.
This led to increased enrollment in Medicaid since most new beneficiaries were uninsured previously, Rose said.
To examine whether this expansion of Medicaid eligibility led to earlier cancer detection, the Case Western Reserve researchers analyzed data on 12,760 Ohio adults aged 30 to 64 who were diagnosed with invasive breast, cervical, colorectal or lung cancer between 2011 and 2016 and were uninsured or had Medicaid insurance at the time of diagnosis.
They compared data before Medicaid expansion -- 2011 to 2013 -- and after Medicaid expansion -- 2014 to 2016 -- and focused on whether patients were diagnosed with early, or non-metastatic, or advanced, or metastatic, cancer.
As a control, the researchers conducted a separate analysis that focused on individuals with private insurance from high-income communities. People in these communities were only 2 percent more likely to diagnosed with non-metastatic cancer post-expansion.
This, the researchers said, suggested that the law had little effect on the already insured population.
"Access to care matters," Rose said. "Broadly speaking, catching cancer at an earlier stage improves one's chances of survival -- especially if it can be caught before the cancer metastasizes.
"The ability to see a healthcare provider in non-emergency situations provides the opportunity for screening to occur."