(CNN) The expansion of the Medicaid program -- a major part of the Affordable Care Act -- has helped black cancer patients receive more timely treatment in states where expansion took place, according to new research.
The research, presented at the American Society for Clinical Oncology's annual meeting in Chicago on Sunday, suggests that the implementation of Medicaid expansions has played a role in reducing some racial disparities in access to cancer care.
While anyone can qualify for Medicaid based on income, household size, disability, family status and other factors, the ACA gives states the option to expand Medicaid eligibility so that residents can qualify based solely on whether their household income level is a certain percentage below the federal poverty line.
Enrollments for insurance under the ACA, or Obamacare, began in 2014.
The new research involved assessing data on 34,067 adults aged 18 to 64 who were diagnosed with advanced or metastatic cancer between 2011 and 2018, which included information before and after ACA enrollments.
The data came from the nationwide electronic health record-derived database at Flatiron Health, a health care technology and services company. Flatiron Health funded the research.
The researchers took a close look at whether cancer patient's treatment was "timely," defined as whether treatment began within 30 days of the diagnosis. The researchers also assessed that data by race and whether the patient's state of residence had expanded Medicaid as of the time of their diagnosis.
The researchers found that before expansion, black patients were 4.9 percentage points less likely to receive timely treatment, but "prior racial disparities were no longer observed after Medicaid," the researchers wrote in their study's abstract.
Expansion "was associated with a differential benefit" of 6.9 percentage points for black patients and 1.8% percentage points for white patients, the researchers found.
The study had some limitations, including that more research is needed to determine whether similar differences by race would emerge among groups other than just white and black cancer patients.
The study abstract also did not include data on survival or other outcomes.
"Regardless of race, Medicaid expansion trended toward an increase in timely treatment overall," the researchers wrote.
The new findings came as no surprise to Dr. Georges Benjamin, executive director of the American Public Health Association, who was not involved in the research.
"It tells you that insurance is important. Insurance matters," Benjamin said.
"It's not surprising that you get a better improvement or a differential improvement when you actually provide that service," he said. "Even though there was a differential improvement in minorities, there was also an improvement in non-minorities. So the point is that it helps everybody."
Benjamin also pointed out how several separate studies previously have shown improvements in public health associated with Medicaid expansion.
For instance, a study that published last year in the American Journal of Public Health found that declines in infant death rates between 2010 and 2016 were greater in Medicaid expansion states, with greater declines among black infants, compared with states that did not expand Medicaid.
"So again you're beginning to see more and more of this evidence that the states that did not expand are putting their citizens at extraordinary risk, which is preventable," Benjamin said. "They're missing an opportunity to improve the health of their population and with this new cancer study, it shows that they're also missing an opportunity to address issues around health equity."
Outside of racial disparities, there have been major state-by-state health disparities that have emerged regarding not only cancer care but also overall health risks, said Dr. Otis Brawley, Bloomberg distinguished professor of oncology and epidemiology at Johns Hopkins University in Baltimore, who was not involved in the research.
"There's growing concern about Massachusetts versus Mississippi differences. State-by-state disparities are now the big problem," Brawley said, because some states expanded Medicaid and others did not.
"It is simply greater access to care," he said. "What we're doing is we're giving access to care to people who did not have access to care by expanding Medicaid. We're making good doctors and good health care available to people who used to not have it."
Yet some experts question whether access to Medicaid is tantamount with access to continuous quality care.
"It is important to note that access to health insurance is not synonymous with access to care," said Chau Trinh-Shevrin, vice chair for research in the Department of Population Health at NYU School of Medicine in New York, who was not involved in the research.
She said that access to insurance may lead to faster immediate care, but it may not reflect the full spectrum of what happens along the cancer care continuum when it comes to follow-up and treatment visits. It also may not reflect quality of care.
"In some respects, it is premature to note that ACA expansion reduced the cancer disparities gap with treatment time as the primary outcome," Trinh-Shevrin said.
"The literature on cancer disparities indicate a large range of social determinants of health that influence access and utilization of cancer screening, care and treatment -- that range from stigma, limited English proficiency, low health literacy, limited social support, or difficulties in navigating the US healthcare system," she said.