Cancer Patients Need to Know the Numbers When Making Treatment Decisions

Cancer Patients Need to Know the Numbers When Making Treatment Decisions

Risk calculations, treatment evaluations, and assessing the odds of a medication’s side effects are all part of the process of deciding which treatment is best for breast and other cancers.

But not everyone is good at math, and sometimes this process can be intimidating. For these patients, decision science research can offer well-founded advice on how to evaluate the information and make knowledgeable decisions.

Research on cancer patients’ health and numeracy was presented by Ellen Peters, a professor at The Ohio State University and director of the Decision Sciences Collaborative, at the annual meeting of the American Association for the Advancement of Science on Feb. 20 in Boston.

“The ability to understand numbers is associated with all kinds of positive health outcomes, including for cancer patients,” Peters said in a press release.

“The problem is that too many people aren’t good with numbers or are afraid of math. But we’re starting to figure out the best ways to help these patients so they aren’t at a disadvantage when it comes to their treatment,” she said.

People who aren’t good with numbers often report worse health outcomes, which Peters said is an example of the “tyranny of numbers.” For example, diabetic patients with lower numeracy scores often have higher blood sugar levels, an effect that often passes on to their children.

Another example from a 2010 research study showed how numeracy can also impact breast cancer treatment decisions. Women who had undergone surgery were presented with four treatment options (hormonal, chemotherapy, combined treatment, or no treatment). Patients were then asked to estimate their own chances of survival. Researchers found that those with higher numeracy scores were more pessimistic than the data, but their estimates varied more than patients with lower numeracy scores.

“For those who were less numerate, their survival estimates were pessimistic, but remained the same no matter what numbers they were presented. It was as if they didn’t read the numbers at all,” Peters said. “This is critical. We were giving them information that should help them choose the best treatment, but they were ignoring it.”

For Peters, evidence suggests that less numerate people tend to rely more on their emotional responses to make health-related decisions and are also more influenced by how the information is presented than by the information itself.

Peter suggests four strategies to not disregard information itself, despite of how it is presented:

  • Ask for the numbers. Although it might seem counterintuitive, studies show that when we have access to the numbers behind the risk of side effects from a certain medication we do better than when we don’t have access to any numbers at all.
  • Ask about the numbers. Don’t be afraid to ask. Doctors should be able to tell you what the numbers mean in practical terms. Ask your doctor about average results, if he thinks these are good results compared to other options, or any other questions you might feel are important.
  • Ask for absolute risk. Saying a specific drug doubles your risk of a dangerous side effect might sound scary, but this is only a relative risk. Absolute risk will tell you if you’re going from a 0.01 percent to 0.02 chances of developing a certain side effect, or if you’re going from 10 percent to 20 percent, which is a completely different result.
  • Reduce your options. If you’re given a never-ending list of treatment choices, ask your doctor for help choosing the best two to consider. Your doctor should understand that all this information might be unintelligible to you and should be able to help you decide which options are best.

Peters said it is critical that patients are aware of the questions they need to ask when making these type of decisions.

“Numbers are important, whether you like them or not. And nowhere are they more important than when it comes to your health,” she added.