The Author's Response: Assessment of Breast Cancer Patients' Knowledge and Decisional Conflict Regarding Tamoxifen Use.

We appreciate their interest in our article entitled “Assessment of Breast Cancer Patients’ Knowledge and Decisional Conflict Regarding Tamoxifen Use” (1) and would like to thank them for sharing their scientific views. The studies that they mentioned are valuable for understanding patients’ conflicts that may occur in their decisional process to start tamoxifen treatment.

However, compared with those studies, our study had a different point of view. Our study mainly focused on the relationship between breast cancer patients’ tamoxifen-related knowledge and decisional conflicts. For this purpose, we newly developed a 15-item questionnaire to measure patients’ tamoxifen-related knowledge. This questionnaire set, reviewed by experts and validated, has its own originality. To measure patients’ decisional conflicts regarding tamoxifen use, the Decisional Conflict Scale (DCS) was used. By comparing the results of the knowledge scale and the DCS, we found that breast cancer patients with higher levels of tamoxifen-related knowledge showed lower levels of decisional conflict regarding tamoxifen use.

In this study, we also attempted to find out other factors that might affect patients’ decisional conflicts. To measure breast cancer patients’ health status, the EQ-5D was used. As they mentioned, the patients’ physical, role, emotional, cognitive, and social functioning altogether may affect their decisional conflict. We believe that a more delicate questionnaire such as the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) might be useful to assess cancer patients’ quality of life. The EORTC QLQ-C30 especially consists of not only functioning scales but also symptom scales.

We agree that ethnicity and cultural background may affect patients’ decisional conflicts. In addition, socio-medical environment should be considered. Under the different health insurance systems, the cost-effectiveness of tamoxifen treatment for breast cancer patients might be rated differently, resulting in different impact on patients’ decisional processes.

Owing to the retrospective design, we admit that our study had several limitations. However, as breast cancer patients’ tamoxifen-related knowledge level affects their decisional conflict, we would like to emphasize clinicians’ role in medical practice. To aid patients’ decision making with minimal conflict, clinicians should provide the exact information about tamoxifen treatment to patients. Individual educational programs should be applied on the basis of patients’ knowledge assessment results.

Our study group designed a randomized controlled study that aimed to investigate the efficacy of educational programs and decision aids for tamoxifen treatment in the breast cancer patients, and the study is now in the registration stage (Available at: http://clinicaltrials.gov/show/NCT02094495). Whether higher levels of tamoxifen-related knowledge in breast cancer patients affect their actual use of the drug positively or negatively can be elucidated clearly through the study outcomes.