Breast cancer is the most common type of
female cancer.
Tamoxifen, a
selective estrogen receptor modulator, is widely used to decrease
breast cancer recurrence and
mortality among
patients. However, it also increases the
risk of
endometrial cancer. This study aimed to assess
knowledge and decisional conflict regarding
tamoxifen use. Between June and October 2014,
breast cancer patients using
tamoxifen were consecutively screened and requested to complete a
survey including the EQ-5D,
Satisfaction with
Decision Scale (SWD), Decisional Conflict Scale (DCS), and a
self-developed, 15-item
questionnaire measuring
tamoxifen-related
knowledge. The study sample comprised 299
patients. The mean total
knowledge score was 63.4 of a possible 100.0 (range, 13.3-93.3). While 73.9% of the participants knew that
tamoxifen reduces the
risk of
breast cancer recurrence, only 57.9% knew that the
drug increases
endometrial cancer risk. A
higher education level (> or =college) was associated with a higher, total
knowledge score (beta = 4.291; P = 0.017). A higher
knowledge score was associated with a decreased DCS score (beta = -0.366; P < 0.001). A higher SWD score was also associated with decreased decisional conflict (beta = -0.178; P < 0.001). In conclusion, the
breast cancer patients with higher levels of
tamoxifen-related
knowledge showed lower levels of decisional conflict regarding
tamoxifen use. Clinicians should provide the exact information about
tamoxifen treatment to
patients, based on
knowledge assessment results, so as to
aid patients'
decision-making with minimal conflict.