, Volume 5, Issue 6, pp 433-440
Date: 09 Aug 2012

Effects of Switching from Tamoxifen to Anastrozole on Tamoxifen-Related Endocrine Symptoms and Quality of Life

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Abstract

Objective:To determine the effects on menopausal symptoms and quality of life of switching from tamoxifen to anastrozole as adjuvant endocrine treatment for early breast cancer patients.

Patients and methods:Forty-four women who had completed primary breast cancer treatment (surgery ± radiotherapy ± chemotherapy), were postmenopausal, and had switched from tamoxifen to anastrozole as adjuvant hormonal treatment because of tolerability issues were enrolled. Endocrine symptoms and health-related quality of life were assessed by the series of Functional Assessment of Cancer Therapy-Breast (FACT-B) and endocrine subscale (ES) questionnaires at the time of the switch and 12 months later, and by the ES alone at 3, 6, and 9 months after switching. Sample size was decided by the effect size method, with a standard deviation fixed at 0.5, the conventionally accepted value representative of an effect of medium value. To evaluate score modifications, one-way ANOVAs were applied.

Results:Endocrine symptoms improved between baseline and 3 months and stabilized thereafter. Improvements in mean ES scores from baseline were +3 (95% CI 1, 5), +4 (95% CI 3, 6), +5 (95% CI 3, 7), and +4 (95% CI 3, 6) at 3, 6, 9, and 12 months, respectively. The FACT-ES global score showed a mean improvement over 12 months of 9 points (95% CI 6, 13; p < 0.0005). A statistically significant improvement in Trial Outcome Index scores from baseline to 12 months (+4 points [95% CI 2, 6; p < 0.0005]) and in the physical and breast cancer subscales (+2 [95% CI 1, 2; p < 0.001] and +1 [95% CI 1, 2; p < 0.001]) was also observed. Compared with tamoxifen treatment, patients receiving anastrozole reported significantly higher rates of mild arthritic and bone pain (27%vs 7%; p = 0.021)

Conclusion:This study evaluated a small population of 44 patients who had switched from tamoxifen to enastrozole mainly because of gynecologic adverse effects with tamoxifen. However, the results of this study suggest that a change to anastrozole as adjuvant therapy should be considered for patients who develop endocrine symptoms while receiving tamoxifen to minimize those symptoms and improve quality of life.