A large national survey of cancer patients found that income strongly predicts the likelihood a patient will participate in a clinical trial, raising concern that lower-income patients don’t have equal access to clinical trials.

Even in patients over age 65, most of whom are enrolled in Medicare, lower income predicted reduced clinical trial participation.

“Prior research has shown some association between cancer clinical trial enrollment and income, but the income measures were indirect. This is the first time in a large, national study that we have actual patient-reported income on which to base this finding,” said the study’s lead author, Joseph M. Unger, MS, PhC, a health services researcher and statistician with the SWOG Statistical Center at the Fred Hutchinson Cancer Research Center, Seattle, WA.

“Our study found that after accounting for all factors such as age, education, sex, race, medical conditions, and distance to a clinic, income on its own was associated with a patient’s clinical trial participation.”

In the study, 5,499 newly diagnosed cancer patients were surveyed from 2007 to 2011, using a web-based treatment decision tool in which patients reported their data.

Eligible patients had a new diagnosis of breast, lung, colorectal, or prostate cancer and were over age 18.

Patients who reported annual income less than $50,000 were about 30 percent less likely to participate in a clinical trial than those reporting higher income. Looking at lower income levels, patients who made less than $20,000 a year were 44 percent less likely to participate in clinical trials than patients who made more than $20,000.

Of all the patients surveyed, 40 percent had discussed clinical trials with their physicians; 45 percent of these discussions led to offers of clinical trial participation; and 51 percent of offers led to enrollment in a clinical trial. The overall clinical trial participation rate was 9 percent.

The study also found that concern about how to pay for participating in a clinical trial was much higher among lower-income patients. While this study didn’t assess what specific cost concerns led patients not to participate in trials, possible barriers to trial participation may include direct costs, such as co-pays and co-insurance, or indirect costs, such as having to take time off work to go for a clinic visit, though these costs are also borne by people undergoing cancer treatment outside of clinical trials.

The researchers will be examining data from another study that followed a cohort of patients over time to further assess the relationship between income and clinical trial participation.

A better understanding of why income is a barrier may identify ways to make clinical trials more available to all patients. 

Source: ASCO