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Randomized Placebo Controlled Trial of Low-Dose

    • 1209 posts
    August 8, 2019 11:22 AM EDT
    Tamoxifen administered for 5 years at 20 mg/d is effective in breast
    cancer treatment and prevention, but toxicity has limited its broad use.
    Biomarker trials showed that 5 mg/d is not inferior to 20 mg/d in
    decreasing breast cancer proliferation. We hypothesized that a lower
    dose given for a shorter period could be as effective in preventing
    recurrence from breast intraepithelial neoplasia but have a lower
    toxicity than the standard dose.Nolvadex uses

    We conducted a multicenter randomized trial
    of tamoxifen, 5 mg/d or placebo administered for 3 years after surgery
    in women with hormone-sensitive or unknown breast intraepithelial
    neoplasia, including atypical ductal hyperplasia and lobular or ductal
    carcinoma in situ. The primary end point was the incidence of invasive
    breast cancer or ductal carcinoma in situ.

    Five hundred women 75 years of age or younger were
    included. After a median follow-up of 5.1 years (interquartile range,
    3.9-6.3 years), there were 14 neoplastic events with tamoxifen and 28
    with placebo (11.6 v 23.9 per 1,000 person-years; hazard ratio, 0.48;
    95% CI, 0.26 to 0.92; P = .02), which resulted in a 5-year number needed
    to treat of 22 (95% CI, 20 to 27). Tamoxifen decreased contralateral
    breast events by 75% (three v 12 events; hazard ratio, 0.25; 95% CI,
    0.07 to 0.88; P = .02). Patient-reported outcomes were not different
    between arms except for a slight increase in frequency of daily hot
    flashes with tamoxifen (P = .02). There were 12 serious adverse events
    with tamoxifen and 16 with placebo, including one deep vein thrombosis
    and one stage I endometrial cancer with tamoxifen and one pulmonary
    embolism with placebo.
    Breast intraepithelial neoplasia, including
    atypical ductal hyperplasia (ADH), lobular carcinoma in situ (LCIS), and
    ductal carcinoma in situ (DCIS), has a five to 10 times higher risk of
    developing into invasive breast cancer compared with the general
    population and accounts for 15% to 25% of breast neoplasms on the basis
    of screening mammography.1 The natural history of breast intraepithelial
    neoplasia is heterogeneous. Some forms remain indolent, whereas other
    forms can progress to life-threatening invasive disease, which has led
    to controversial issues with regard to its optimal approach.1,2