Patient-Reported Outcomes With Adjuvant Anastrozole vs Tamoxifen in Postmenopausal Women With Ductal Carcinoma in Situ
As reported in The Lancet and at the recent San Antonio Breast Cancer Symposium, Ganz et al found differences in patient-reported outcomes with anastrozole vs tamoxifen in the phase III National Surgical Adjuvant Breast and Bowel Project (NSABP) B-35 trial in postmenopausal women with hormone receptor–positive ductal carcinoma in situ who had undergone lumpectomy and whole-breast irradiation. Anastrozole was associated with worse musculoskeletal pain and vaginal symptoms; tamoxifen was associated with worse vasomotor symptoms, difficulty with bladder control, and gynecologic symptoms.
Study Details
In NSABP B-35, 3,104 patients were randomly assigned to receive daily anastrozole at 1 mg (n = 1,552) or tamoxifen at 20 mg (n = 1,552) for 5 years. The trial showed that anastrozole was associated with improved breast cancer–free interval, with significant benefit limited to patients aged < 60 years.
Patient-reported outcomes were assessed every 6 months. The primary outcomes were the Medical Outcomes Study (MOS) Short Form (SF)-12 physical and mental health component scale scores and vasomotor symptoms on the Breast Cancer Prevention Trial (BCPT) symptom scale. Other outcomes were assessed using the SF-36 vitality scale, Center for Epidemiologic Studies Depression Scale, and MOS sexual problems scale.
Differences in Patient-Reported Outcomes
A total of 1,193 patients, consisting of 592 anastrozole recipients and 601 tamoxifen recipients, were included in the analysis. No significant differences between groups were observed for physical health scores (P = .20), mental health scores (P = .38), energy and fatigue (P = .86), symptoms of depression (P = .46), or sexual functioning (P = .56) over 5 years. Vasomotor symptoms (P = .011), difficulty with bladder control (P = .0002), and gynecologic symptoms (P < .0001) were rated as significantly more severe by patients in the tamoxifen group; the difference in vasomotor symptoms was significant at 6, 12, 30, and 36 months. Musculoskeletal pain (P = .0006) and vaginal symptoms (P = .035) were rated as significantly worse in the anastrozole group; the difference in musculoskeletal pain was significant at 6, 12, and 24 months.
After adjustment for treatment, age < 60 years vs ≥ 65 years was associated with more severe vasomotor symptoms (P = .0006), vaginal symptoms (P < .0001), weight problems (P < .0001), and gynecologic symptoms (P = .014).
The investigators concluded: “Given the similar efficacy of tamoxifen and anastrozole for women older than age 60 years, decisions about treatment should be informed by the risk for serious adverse health effects and the symptoms associated with each drug. For women younger than 60 years old, treatment decisions might be driven by efficacy (favoring anastrozole); however, if the side effects of anastrozole are intolerable, then switching to tamoxifen is a good alternative.”
The study was funded by the National Cancer Institute and AstraZeneca Pharmaceuticals.
Patricia A. Ganz, MD, of Jonsson Comprehensive Cancer Center, University of California, Los Angeles, is the corresponding author of The Lancet article.
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