Abstract

Purpose: The primary purpose of this study was to examine the influence of three different methods of describing the efficacy of chemotherapy on treatment decisions regarding management of metastatic colorectal cancer. The secondary purpose was to compare treatment modality preferences for metastatic colorectal cancer when the method of communicating treatment efficacy is held constant.
Methods: In part I of the study, participants received a hypothetical scenario regarding their mother, who was recently diagnosed with recurrent metastatic colorectal cancer, and were asked to decide whether or not they would encourage her to take chemotherapy. Participants were randomly assigned to receive 1 of 3 ways of describing the efficacy of chemotherapy: (1) relative risk reduction; (2) tumor response rate; and (3) median overall survival. In part II, participants received the same scenario, but were presented four treatment options and the accompanying median overall survival estimate: (1) observation and supportive care; (2) chemotherapy; (3) surgery; and (4) surgery and chemotherapy.
Results: Participants included 102 pre-clinical medical students. In part I, participants randomly assigned to receive the median overall survival method endorsed chemotherapy significantly less often than participants who received the relative risk reduction or response rate methods. In part II, participants overwhelmingly preferred combined modality therapy in comparison to the other three treatment options offered.
Conclusions: These results support the hypothesis that the method used to present information about chemotherapy influences treatment decisions and that combined modality treatment is preferred when it is offered.

Introduction

Purpose &Hypotheses
• The purpose of the study was to examine if the method used to describe the efficacy of chemotherapy influences treatment decision-making for metastatic colorectal cancer.
• Specifically, we hypothesized that…
– Describing outcomes using relative risk reduction or tumor response rate would lead to significantly greater endorsement of chemotherapy.
– When holding constant the method used to communicate the benefits of treatment for metastatic colorectal cancer, multimodality treatment would be selected significantly more often than single modality treatment (i.e., chemotherapy, surgery, or supportive care).

Method

Vignette
• Clinical Scenario
• Respondents were asked to determine whether they would advise their mother to take chemotherapy after 3 tumors found in her liver had been diagnosed as metastatic colorectal cancer
• Two Parts to the Clinical Scenario

Part I:
• Participants were randomly assigned to receive 1 of 3 methods of communicating treatment efficacy information

Part II
• Participants received 4 treatment options and the method of communicating treatment efficacy information was held constant, using median overall survival data

Part I: Methods of Treatment Efficacy Communication
• Relative Risk Reduction
– With no treatment, her risk of dying in the next year is 100%. By having chemotherapy, she will reduce her relative risk of death in the next year by 50%.
• Tumor Response Rate
– With no treatment, her chance of demonstrating a response of her metastatic lesions is nearly 0%. By having chemotherapy, her chance of demonstrating a response is 42%.
• Median Overall Survival
– With no treatment, her median overall survival will be 5.7 months. By having chemotherapy, her median overall survival will be 8.8 months – an increase of 3.1 months

Part II: Treatment Options
• Supportive Care
– If you choose no additional treatment except OBSERVATION AND SUPPORTIVE CARE, her median overall survival will be 5.7 months.
• Chemotherapy
– If you choose CHEMOTHERAPY ONLY, her median overall survival will be 8.8 months.
• Surgery
– If you choose SURGERY ONLY, her median overall survival will be 36 months.
• Surgery + Chemotherapy
– If you choose SURGERY + CHEMOTHERAPY, her median overall survival will be 50 months.

Sample Descriptions (N = 102)
• 70% were 2nd year medical students
• 84% were of European American descent
• 68% were single
• 54% were female
• 79% had a personal/family history of cancer
• 62% had a personal/family history of having taken chemotherapy
• 65% had a personal/family history of having had cancer surgery

Study Variables
• Treatment Decisions
– Part I: Treatment Endorsement
• Yes or No
– Part II: Treatment Selection
• Supportive Care
• Chemotherapy
• Surgery
• Surgery + Chemotherapy (Combined Treatment)
• Decision Correlates
– Sociodemographic characteristics
– Pre-test Treatment Attitudes
• Perceived Utility of Surgery and Chemotherapy
• Perceived Tolerability of Surgery and Chemotherapy

Results

Part I: Chemotherapy Decision: Methods of Treatment Efficacy Communication

Percentage of participants endorsing chemotherapy, given each method of communication:

Relative Risk Reduction: 85%

Tumor Response Rate: 88%

Median Overall Survival: 35%

Overall: 69%

Part II: Overall Treatment Decision: Single Modality vs. Combined Modality Treatment

Percentage of Participants Selecting Treatment Modality

Supportive Care Only: 4%

Surgery Only: 19%

Chemotherapy Only: 0

Variables Related to Treatment Decisions
Sociodemographic Variables and Treatment Attitudes
• Part I
– Participants who endorsed chemotherapy in Part I reported significantly higher perceived tolerability of
chemotherapy, higher perceived utility of chemotherapy, and higher perceived utility of surgery.
– Endorsing chemotherapy was not related to any sociodemographic variables.
• Part II
– Participants who endorsed combined treatment in Part II reported significantly higher perceived utility of
chemotherapy
– No other sociodemographic or treatment attitude variables were related to treatment decisions.

Conclusions

1) Methods used to communicate treatment efficacy can have a significant impact on oncology treatment decision-making.
2) Participants preferred combined modality treatment for metastatic colorectal cancer, likely due to increased survival estimates.
3) Pre-test attitudes toward chemotherapy (tolerability and overall utility) seemed to have a significant impact on willingness to endorse this oncology treatment option.

Limitations

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