(Reuters Health) - After the Affordable Care Act (ACA) helped reduce the number of uninsured Americans, more low-income adults got cancer diagnosed when it was less advanced and potentially easier to treat, a recent study suggests.

Researchers examined data on 1.7 million adults under age 65, of all income levels, who were newly diagnosed with cancer between 2011 and 2014. About 907,000 participants lived in states that expanded Medicaid, the government-sponsored insurance for the poor, under the ACA. Another 811,000 people lived in states that didn’t expand Medicaid.

The effect of expanded Medicaid was most pronounced for low-income patients. Before the ACA took effect, in the states that subsequently added to their Medicaid rolls, 9.6 percent of low-income people newly diagnosed with cancer were uninsured. Afterward, only 3.6 percent of poor, newly diagnosed cancer patients lacked health coverage in these states.

The decline in the proportion of newly diagnosed patients without insurance was much less pronounced in states that didn’t expand Medicaid. In these states, the proportion of low-income newly diagnosed cancer patients without insurance dropped from 14.7 percent before the ACA to 13.3 percent afterward.

In Medicaid expansion states, there was also a small but statistically meaningful increase in the proportion of patients newly diagnosed with colorectal, lung, breast, pancreatic and melanoma cases that were caught when tumors were in the early stages of development.

“Although the increase in the percent of patients diagnosed with early-stage diseases in Medicaid expansion states is small, it has significant clinical implications,” said lead study author Ahmedin Jemal, vice president of surveillance and health services research at the American Cancer Society in Atlanta.

“Patients diagnosed with early-stage diseases are more likely to be treated successfully and to be cured and to have better quality of care,” Jemal said by email. “Furthermore, the increase in detection of cancers at early stage has societal implications by avoiding premature deaths when individuals are in the workforce, raising children and supporting other family members.”

These results suggest a need for additional expansion of access to care, especially for low-income populations, the authors conclude in the Journal of Clinical Oncology.

To assess the impact of the ACA and the expansion of Medicaid programs, researchers examined data from the National Cancer Data Base.

For a picture of what happened before the ACA took effect at the beginning of 2014, they looked at data from 2011 through the third quarter of 2013. To see what happened afterward, they examined data from the second to fourth quarter of 2014

They looked at changes in insurance and in early-stage diagnosis for 15 leading cancers in men and women.

The study wasn’t a controlled experiment designed to prove that the ACA or Medicaid expansion directly caused more low-income people to be diagnosed with cancer sooner. The study also didn’t follow people to determine if this resulted in better survival odds or other benefits.

Researchers also didn’t follow people beyond the first year of Medicaid expansions. Previous research has found that coverage gains, access to care and health benefits of expanding Medicaid increase over time, said Dr. Benjamin Sommers, a health policy and economics researcher at the Harvard T. H. Chan School of Public Health and Brigham and Women’s Hospital in Boston.

“However, coverage expansion on its own may not necessarily lead to more early stage cancer (diagnoses), especially cancers for which we don’t have effective screening tests,” Sommers, who wasn’t involved in the study, said by email.

And it’s too soon to expect to see dramatic changes in survival rates, said Dr. Ernest Hawk of the University of Texas MD Anderson Cancer Center.

“Nevertheless, the reduction in the number of newly diagnosed cancer patients in conjunction with the downward stage-shift documented in this study is a promising step towards helping to address the disparities in cancer outcomes, including survival,” Hawk, who wasn’t involved in the study, said by email.

SOURCE: bit.ly/2f9A5aN Journal of Clinical Oncology, online September 8, 2017.