Abstract P6-11-01: Field testing of a point-of-care decision support tool for contralateral prophylactic mastectomy
Authors: Brewster AM , Cantor S , Davies K , Bedrosian I , Parker P , Garrison S , Volk RJ 
Published: May 2019

Background: The majority of women undergoing contralateral prophylactic mastectomy (CPM) overestimate their risk of developing a contralateral breast cancer and incorrectly believe the CPM will substantially improve their overall survival. Using the results of our published micro-simulation decision-analytic model (Davies et al. Breast Cancer Res, 2016), we created and tested a CPM decision support tool to provide patients and breast cancer surgeons with individualized estimates of contralateral breast cancer risk and overall mortality.

Methods: The CPM decision support tool had four entry parameters from the micro-simulation model (age, family history of breast cancer, estrogen receptor status, and stage), and a visual depiction of outcomes using icon arrays for chances of developing a contralateral breast cancer and overall mortality with and without CPM. A user-centered design strategy was used with input and iterative refinement from stakeholders, i.e., breast cancer surgeons, patient advocates and breast cancer survivors. The tool was field-tested at MD Anderson Cancer Center with 5 breast cancer surgeons each using the tool with 5 breast cancer patients considering CPM (25 total). Patients completed a knowledge survey immediately before and after viewing the tool and the Decisional Conflict Scale (DCS) after viewing the tool. Surgeons completed the System Usability Scale (SUS) and ratings of the acceptability of the tool.

Results: The mean age of patients was 58 years. All patients reported the tool was helpful in making a decision about CPM and would recommend it to others. Knowledge of breast cancer and key CPM facts increased from before to after using the tool (64% vs. 75%, respectively, P&lt;0.05). The mean score on the DCS was 10.5 (standard deviation =14.3) indicating patients were overall sure about the CPM choice. The majority (72%) of patients were unsure of their interest in CPM before viewing the tool. After viewing the tool, 13 (52%) of patients indicated they did not want CPM, 4 (16%) indicated they wanted CPM, and 8 (32%) remained unsure. Surgeons rated the tool as having a positive impact on the decision-making process and SUS scores were highly favorable (mean 93 on 0-100 scale, with 100 indicating highest usability).

Conclusion: The CPM decision tool had high overall patient satisfaction and improved knowledge about CPM without affecting decisional conflict. Decision support tools may be used to improve the quality of decision-making about CPM by providing surgeons and their patients with useful individualized information about CPM's impact on relevant clinical outcomes, which may lower the incidence of CPM.

Citation Format: Brewster AM, Cantor S, Davies K, Bedrosian I, Parker P, Garrison S, Volk RJ. Field testing of a point-of-care decision support tool for contralateral prophylactic mastectomy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-11-01.