Confusing risk information may lead breast cancer patients to make poor treatment choices

December 8, 2008

A new study from researchers at the University of Michigan Comprehensive Cancer Center found that a tool commonly used by doctors to estimate the risk of a woman's breast cancer returning after surgery is not very effective at explaining risk to patients. As a result, women with breast cancer may not find these tools helpful when deciding whether to have chemotherapy.

The tool itself is very useful to doctors, many of whom print out information from this tool and give it to patients when they are discussing chemotherapy. Nearly all women diagnosed with early stage breast cancer will have surgery, but many will also consider chemotherapy to help prevent the cancer from coming back.

"The main benefit of additional treatments such as chemotherapy after surgery is long-term risk reduction. But chemotherapy does not provide much benefit for some women, and those women can potentially avoid unnecessary side effects by skipping chemotherapy. So understanding how large or small the risk reduction is can help women make the right choice," says lead study author Brian Zikmund-Fisher, Ph.D., research assistant professor of general medicine at the U-M Medical School and a researcher at the VA Ann Arbor Healthcare System.

The currently available risk-assessment tools present risk statistics in a bar graph format that compares four different potential choices: hormonal therapy alone, chemotherapy alone, both hormonal and chemotherapy, or no treatment at all. The problem, Zikmund-Fisher points out, is that most women are really only choosing between two options: For women whose cancers are sensitive to the hormone estrogen, hormonal treatments provide large benefits with few side effects. The real question is whether chemotherapy is also necessary.

Because the tool shows statistics about all four options, however, the researchers found that it is more difficult for women to find and focus on the number that most matters to their choice: the benefit of adding chemotherapy to hormonal therapy.

In the study, published Dec. 15 in the journal Cancer, researchers surveyed 1,619 women, presenting them with a hypothetical breast cancer diagnosis. All women were given identical risk factors for recurrence. The women viewed one of four graphical formats to describe how chemotherapy would reduce the risk of dying from a return of cancer.

When respondents saw the risk information in the bar graph format that current risk-assessment tools use, only 51 percent correctly understood how much their chance of surviving would increase if they took chemotherapy. When women were shown a simpler graph that showed only the two key options, 65 percent were accurate. And, when the simpler graph used a pictograph format that showed a set of 100 small rectangles to represent the possible outcomes, a full 77 percent were able to correctly report the benefit of chemotherapy.

"Even when patients are given the information they need, they have to be able to understand it well enough to make the right choice. We're making patients work too hard. Discussions of risk need to be simple and transparent so doctors can spend as little time as possible explaining the numbers to patients and as much time as possible talking about what those numbers mean. That's the best way to make sure that each patient can make the right choice for her situation," says Zikmund-Fisher, a member of the Center for Behavioral and Decision Sciences in Medicine at U-M.

The researchers hope that eventually these risk tools will incorporate better ways to show these risks to both doctors and patients. In the meantime, Zikmund-Fisher suggests that patients confused about risk information think of it in terms of frequency, rather than percentages. In other words, if you are told you have an 82 percent chance of surviving 10 years, imagine there are 100 people just like you and that 82 of them are still alive to come back to a 10-year reunion.

"Thinking about those different people and what happens to each of them will help you to realize both possible outcomes and how likely each one is," Zikmund-Fisher says.

Source: University of Michigan Health System

Explore further: Joan lunden's breast cancer journey: 'You feel so vulnerable'

Related Stories

Joan lunden's breast cancer journey: 'You feel so vulnerable'

October 26, 2017
(HealthDay)—Joan Lunden—co-host of "Good Morning America" for nearly two decades and a long-time health advocate—is now also a breast cancer survivor.

Is freezing human eggs really 'extremely unsuccessful'?

November 9, 2017
Freezing eggs is extremely unsuccessful. Although it's never admitted, it is true from the national statistics, how poor the chances of pregnancy are afterwards.

Routine mammograms do save lives

November 1, 2017
A recent article published by The Conversation Canada stated routine mammographies do not save lives – and that the harms of screening outweigh the benefits.

New blood test developed to diagnose ovarian cancer

October 31, 2017
Investigators from Brigham and Women's Hospital and Dana-Farber Cancer Institute are leveraging the power of artificial intelligence to develop a new technique to detect ovarian cancer early and accurately. The team has identified ...

Team explores anti-breast cancer properties of soy

October 30, 2017
A University of Arizona Cancer Center research team is engaged in a series of studies to investigate how genistein, a component of soy foods, might suppress the development of breast cancer.

Computer program finds new uses for old drugs

November 16, 2017
Researchers at the Case Comprehensive Cancer Center at Case Western Reserve University School of Medicine have developed a computer program to find new indications for old drugs. The computer program, called DrugPredict, ...

Recommended for you

Study suggests colon cancer cells carry bacteria with them when they metastasize

November 24, 2017
(Medical Xpress)—A team of researchers working at Harvard University has found evidence that suggests a certain type of bacteria found in colon cancer tumors makes its way to tumors in other body parts by traveling with ...

Promising new treatment for rare pregnancy cancer leads to remission in patients

November 24, 2017
An immunotherapy drug can be used to cure women of a rare type of cancer arising from pregnancy when existing treatments have failed.

Researchers unravel novel mechanism by which tumors grow resistant to radiotherapy

November 23, 2017
A Ludwig Cancer Research study has uncovered a key mechanism by which tumors develop resistance to radiation therapy and shown how such resistance might be overcome with drugs that are currently under development. The discovery ...

African Americans face highest risk for multiple myeloma yet underrepresented in research

November 23, 2017
Though African-American men are three times more likely to be diagnosed with multiple myeloma, a type of blood cancer, most scientific research on the disease has been based on people of European descent, according to a study ...

Encouraging oxygen's assault on iron may offer new way to kill lung cancer cells

November 22, 2017
Blocking the action of a key protein frees oxygen to damage iron-dependent proteins in lung and breast cancer cells, slowing their growth and making them easier to kill. This is the implication of a study led by researchers ...

One-size treatment for blood cancer probably doesn't fit all, researchers say

November 22, 2017
Though African-American men are three times more likely to be diagnosed with a blood cancer called multiple myeloma, most scientific research on the disease has been based on people of European descent, according to a study ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.