More cancer patients are now insured because of Obamcare The law has reduced the number of uninsured Americans.

 -- The Affordable Care Act, commonly known as Obamacare, has led to a dramatic decrease in the number of adults with cancer who lacked health insurance, new research shows. But whether future changes to this law could reverse the trend remains to be seen.

“We wanted to understand what the ACA did, especially for vulnerable populations,” according to Aparna Soni, a doctoral candidate at the Kelley School of Business of Indiana University whose research on the topic was published Thursday in the journal JAMA Oncology. “Cancer treatment can be expensive or unaffordable for people without insurance.”

She and other researchers used data from the National Cancer Institute’s Surveillance, Epidemiology and End Results program. They compared pre-ACA (years 2010 to 2013) to post-ACA (2014) data from more than 850,000 adults (ages 19 to 64) without health insurance at first-time cancer diagnosis. They found that the uninsured rate dropped from 5.73 percent to 3.81 percent after the law's implementation – a 33.5 percent relative decrease.

Past research has revealed that numerous socioeconomic factors can determine whether cancer patients live with or die from their cancer; one such factor is insurance coverage. The ACA Health Insurance Marketplaces and state-specific Medicaid expansion significantly reduced the number of uninsured Americans – including those with cancer – after going into effect in 2014.

“[We thought] the ACA would have increased insurance coverage for people with cancer, but we weren’t sure by how much,” Soni said, adding that she was surprised to discover that after the ACA took effect in 2014, “uninsurance among adult patients newly diagnosed with cancer fell by one-third. It was greater than we expected.”

In fact, the percentage of uninsured patients with all types of cancer studied – breast, prostate, colorectal, lung and thyroid – dropped. And this change was seen across all cancer stages as well. Among the races the researchers evaluated, they saw the greatest drop in Hispanics, who had a nearly 40 percent relative decrease. The uninsured rate declined most dramatically in states with Medicaid expansion.

These findings echo those of an article published last month in the Journal of Clinical Oncology, where researchers at the American Cancer Society looked at over 1.7 million adults with the 17 most common types of cancer in the National Cancer Data Base. They found that the number of uninsured among nonelderly adults with newly-diagnosed cancer declined significantly after the ACA, particularly among low-income adults living in Medicaid expansion states.

But as questions loom over the future of the nation’s health care system, Soni said it is uncertain what will happen to the rate of uninsured adults with cancer if parts of the ACA are repealed or replaced.

“There are multiple ways it could go,” she said. “Our hypothesis, based on these findings, is that it could reduce insurance coverage for adults with cancer … but we don’t really know by how much. It is more important now than ever to study the impacts of the Affordable Care Act, in order to understand the implications should the ACA be repealed.”

One of Soni’s next research goals is to examine how health insurance status influences treatment options in relation to cancer stage and mortality. Prior studies have shown that a lack of insurance is associated with higher cancer stage at diagnosis, worse clinical care and increased risk of death following a cancer diagnosis.