THURSDAY, Dec. 6, 2018 (HealthDay News) -- Tamoxifen at a dose of 5 mg/day is associated with a reduced risk for recurrence for women with hormone-sensitive breast intraepithelial neoplasia, according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 4 to 8 in Texas.
Andrea De Censi, M.D., from Ospedali Galliera in Genoa, Italy, and colleagues conducted a phase III trial of tamoxifen (5 mg/day) versus placebo in 500 women with operated hormone-sensitive breast intraepithelial neoplasia.
The researchers identified 14 and 29 recurrences in the tamoxifen and placebo arms, respectively, after a median follow-up of 5.1 years (hazard ratio, 0.48). The incidence rate of events was 11.8 and 24.9 per 1,000 person-years in the tamoxifen and placebo arms, respectively. Most recurrences were invasive breast cancers (78 and 55 percent in the tamoxifen and placebo arms, respectively). Eight and 12 serious adverse events occurred in the tamoxifen and placebo arms, respectively, including two superficial phlebitis and one endometrial cancer in the tamoxifen arm; menopausal symptoms were more frequent in the tamoxifen arm. There were six second primary cancers in the tamoxifen arm and four in the placebo arm; two deaths were reported in the placebo arm.
"When we compare our low-dose tamoxifen data with results from the NSABP B-24 and NSABP-P1 trials of tamoxifen given at 20 mg per day, we see comparable risk reduction and significantly reduced serious adverse events, respectively," De Censi said in a statement.
One author disclosed financial ties to the pharmaceutical industry.