Image-guided core needle biopsy, which uses imaging scans to guide the needle to the site of the suspected cancer, had similar utilization differences -- 25 percent of Medicaid or Medicare patients received this test, compared with 81 percent of patients with private insurance.
The reasons behind the poorer cancer care for Medicaid patients are complex, ASCO spokespeople said.
Patients often have trouble finding a doctor or hospital that participates in Medicaid, because the program traditionally has not paid as well as Medicare or private insurance for medical services, said Patel and Dr. Harold Burstein. He is an ASCO spokesman and an oncologist with the Dana-Farber Cancer Institute in Boston and an associate professor at Harvard Medical School.
On top of that, Medicaid's low-income enrollees have life problems that can hamper their cancer care, such as being unable to get a ride to the doctor or to leave work for an appointment, Patel and Burstein added.
Medicaid patients also tend to have more health problems overall, which means they may put off cancer screening to focus on chronic illnesses like heart disease or diabetes, Chiang noted.
More people than ever are covered by Medicaid or the Children's Health Insurance Program, with 4.8 million additional people joining since the Affordable Care Act marketplaces opened in October 2013. Currently, a total 64.6 million low-income people are covered by the federal health insurance programs.
Doctors hope that increased access to Medicaid under the Affordable Care Act will improve the care patients receive. The law also includes a provision that increases pay for Medicaid services, in an effort to draw more doctors and hospitals to the program.
"What we've seen in Massachusetts is that lots more patients have coverage," Burstein said. "Many people who have been outside the traditional health care system came into the system and began receiving care, and I think that's been good for them."
But these new patients still face problems getting care for cancer, Patel said. Even those who receive cancer screening often fall through the cracks before they can receive treatment.
Patel advocates the use of "nurse navigators" who can act as care managers for Medicaid patients, steering their care and advising them through the complex process of cancer treatment.
"Simply paying for health care and actually showing people the way forward are two different things," Patel said. "When we talk about equity in health care, that's part and parcel of it."