Abstract

Purpose: The study purpose was to examine the impact of four methods of communicating survival benefits on decisions concerning chemotherapy.
Methods: Participants received a hypothetical scenario about their mother who had been diagnosed with breast cancer and were asked to decide whether they would encourage their mother to take chemotherapy in addition to surgery and Tamoxifen. In part I, participants received 1 of 4 methods of describing the chemotherapy survival benefit: 1) relative risk reduction; 2) absolute risk reduction; 3) absolute increase in survival; and 4) number needed to treat. In part II, each participant received all four methods. Participants were also asked to rate their post-decision confidence, confusion, and method preferences.
Results: Participants included 203 pre-clinical medical students. Results showed that participants who received relative risk reduction information were significantly more likely to endorse chemotherapy. There were no treatment decision differences when participants received all four methods of communicating survival benefits of chemotherapy. However, receiving all four methods led to significantly higher ratings of confusion. Participants distinctly preferred the absolute increase in survival information.
Conclusions: These results support the hypothesis that the method used to present information about
chemotherapy influences treatment decisions.

Introduction

Purpose & Hypotheses
• The purpose of the study was to examine the impact of four methods of communicating survival benefits on decisions to
endorse chemotherapy for early stage breast cancer.
• Specifically, we hypothesized that…
– Presenting relative risk reduction (RRR) information will lead to a higher likelihood of endorsing chemotherapy.
– Presenting multiple methods of risk – benefit communication will be associated with higher confusion ratings.
– Presenting a single method of risk – benefit communication will be associated with higher confidence ratings.

Method

Vignette
• Clinical Scenario
• Respondents were asked to determine whether they would advise their mother to take chemotherapy in addition to surgery and Tamoxifen after being diagnosed with a 1.9 cm hormone-sensitive breast tumor
• Two Parts to the Clinical Scenario

Part I:
• Participants were randomly assigned to receive 1 of 4 methods of communicating risk – benefit information

Part II
• Participants received all 4 methods of communicating risk –benefit information

Methods of Risk – Benefit Communication• Relative Risk Reduction
– By adding chemotherapy to her treatment she can reduce her relative risk of death in the next ten years by a little less than 12%.
• Absolute Risk Reduction
– By adding chemotherapy to her treatment she can reduce the risk of death in the next ten years by 2% (from 15% to 13%).
• Absolute Survival Benefit
– By adding chemotherapy to her treatment she can increase the chance of surviving by 2% (from 85% to 87%).
• Number Needed to Treat
– Chemotherapy can be added to her treatment. When 50 patients are treated with chemotherapy, one more patient will survive the next ten
years. (We hope, but do not know, if that person will be your mother).

Outcome Measures• Endorsement of Chemotherapy (Yes/No)
• Confidence & Confusion Ratings
– 7-point Likert Scales after each decision
• Utility Ratings (only Part II)
– Which method was Most Helpful in making your decision?

Sample Description (N = 203)
• 103 (51%) were 2nd year medical students
• 147 (72%) were less than 25 years of age
• 147 (72%) were single
• 101 (50%) were female
• 136 (67%) had a personal/family Hx of Ca
• 96 (47%) had a personal or family Hx of having taken chemotherapy

Results

Chemotherapy Decisions
Part I
Percentage Endorsing Chemotherapy Given Each Communication Method
Relative Risk Reduction: 51%
Absolute Risk Reduction: 39%
Absolute Survival Benefit: 26%
Number Needed to Treat: 31%

Part II
Percentage Endorsing Chemotherapy Given Each Communication Method
Relative Risk Reduction: 71%
Absolute Risk Reduction: 45%
Absolute Survival Benefit: 33%
Number Needed to Treat: 44%

• RRR was endorsed significantly more often than the other methods in Part I.
• There were no significant differences in endorsement rates in Part II.

Confusion Ratings
Part I
Confusion Ratings on a scale of 1-7
Relative Risk Reduction: 2.41
Absolute Risk Reduction: 1.98
Absolute Survival Benefit: 2.00
Number Needed to Treat: 2.12

Part II
Confusion Ratings on a scale of 1-7
Relative Risk Reduction: 2.25
Absolute Risk Reduction: 2.02
Absolute Survival Benefit: 1.90
Number Needed to Treat: 2:30

• There were no significant differences between methods in Parts I and II.
• Confusion ratings were significant higher after Part II than after Part I.

Which Method was Most Helpful?

Percentage Endorsing Each Method as Most Helpful

Relative Risk Reduction: 11%
Absolute Risk Reduction: 11%
Absolute Survival Benefit: 50%
Number Needed to Treat: 25%

• A significant majority of respondents rated ASB as the most helpful method.

Conclusions

– Presenting relative risk reduction (RRR) information led to a twofold increase in chemotherapy endorsement in comparison to other methods of risk – benefit communication.
– Presenting multiple methods of risk – benefit communication led to significantly higher confusion but not lower confidence.
– The absolute survival benefit (ASB) method was rated as the most helpful method by a significant majority of respondents.

Limitations

– The convenience sample of students and the use of clinical vignettes may not be appropriately representative and may not adequately represent the complexity of the chemotherapy decision-making process.