A 5% chance of death or a 10% chance of death: which would you choose?
Imagine that you have been diagnosed with a slow growing cancer. Right now, the cancer is not causing you to feel sick. For most people, the cancer will grow so slowly it will never cause them any trouble. For others, the cancer will grow to the point that it makes them sick. Untreated, five percent (5 out of 100) will die of the cancer. Your doctor tells you that you have two treatment options: watchful waiting or surgery. Watchful waiting means you will not do any treatment right away, but your doctor will follow your cancer closely and treat any symptoms that you have if it begins to spread. Although it would be too late to be cured, you would be comfortable and free of pain. There are no side effects to watchful waiting, but five percent (5 out of 100) of the people who choose this treatment will develop symptoms and die from their cancer within five years. On the other hand, the surgery would cure your cancer permanently. Following surgery you will feel more tired than usual and will experience stomach upset occasionally for the three months following your surgery. However, surgery has a ten percent (10 out of 100) risk of death during the surgery.
Imagine that both of these treatments are completely covered by your health insurance. Which would you choose?
- I would not take the surgery and accept the 5% chance of dying from this cancer.
- I would take the surgery and accept the 10% chance of dying from the surgery.
How do your answers compare?
In the real world, cancer patients sometimes choose treatments that may have devastating side effects over less invasive, yet equally or more effective, approaches. One explanation for this is that people may feel a strong need to "get the cancer out" of their bodies. Surgical removal of all potentially cancerous tissues may satisfy this desire so thoroughly that people end up ignoring important statistical information about adverse outcomes.
Making a choice not in their best interest
CBDSM investigators Angela Fagerlin, Brian Zikmund-Fisher, and Peter Ubel hypothesized that people perceive cancer diagnoses as a call to action, and more specifically, a call to get rid of the cancer through surgery, regardless of what statistical information might say to the contrary. Consequently, they predicted that when presented with hypothetical cancer diagnoses, many people would say they would pursue surgery even if such an action would decrease their chance of survival.
To explore the relative frequency of people's willingness to choose surgery when it wasn't in their best interest, the investigators designed a cancer scenario similar to the one you read on the previous page. Participants were presented either a surgery or a medication treatment that would either increase or decrease their chance of survival.
The investigators found that participants who were presented with the opportunity to rid themselves of their cancer through surgery were significantly more inclined to take action than those who were presented with the medication treatment. For example, when the treatment reduced their overall chance of survival, 65% chose the surgery, whereas only 38% chose the medication treatment. This suggests that people's treatment decisions may be based not on the effectiveness of the treatments, but rather on their beliefs about how cancer should be treated. Specifically, cancer diagnoses seem to conjure up a strong desire for active treatment. And people seem to have an intuitive belief that action should not just involve treatment, but surgical removal of the cancer.
Why these findings are important
The results of this study may resonate with many clinicians who have encountered cancer patients who seem to desire treatment for treatment's sake, or who have a preference for surgical intervention even before they learn about the pros and cons of their treatment alternatives. This study should serve to remind clinicians that patients' preference for action can be strong enough, at times, to be a bias. At a minimum, it is important for health care professionals to be aware of the potential for such biases, so they can decide whether to accept patients' preferences at face value, or try to convince patients that aggressively treating a tumor may not be in their best interests.
Read the article:
Cure me even if it kills me: Preferences for invasive cancer treatment.
Fagerlin A, Zikmund-Fisher BJ, Ubel PA. Medical Decision Making 2005;25(6):614-619.