SABCS 2018 — Low-dose tamoxifen reduces recurrence of breast EIN


  • Tara Haelle
  • Univadis
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Takeaway

  • Low-dose tamoxifen halves the risk for new and recurrent disease among women with intraepithelial neoplasia (IEN) who have undergone surgery, according to data from a phase 3 trial.
  • TAM-01 included women with ductal carcinoma in situ (DCIS), lobular carcinoma in situ, and atypical ductal carcinoma.

Why this matters

  • Toxicity limits compliance with the standard 20-mg dose.
  • 5 mg tamoxifen did not significantly worsen menopausal symptoms or major adverse events vs placebo.

    Key results

    • Median follow-up, 5.1 years.
    • Risk for recurrence was 52% lower with tamoxifen vs placebo (5.5% vs 11.3%; 14 vs 28 events; HR, 0.48; P=.024)
    • Tamoxifen was tied to a decreased risk for contralateral breast cancer (CBC; 3 vs 12 cases; HR, 0.24; P=.018). 
    • 12 serious adverse events with tamoxifen vs 16 with placebo.
    • Rates of venous thromboembolism (VTE) were similar (1 case per group); there was 1 case of endometrial cancer in the tamoxifen group.
      • Expected rates with 20 mg/day tamoxifen would be 2.4 VTE events and 2.7 endometrial cancer cases.
    • 4 other neoplasms with tamoxifen, 6 with placebo.
    • No significant difference between groups for daily hot flash frequency (P=.05) or intensity (P=.18), vaginal dryness/intercourse pain (P=.57), or musculoskeletal pain/arthralgia (P=.84).

    Study design

    • Italian multicenter trial of 500 women with IEN randomly assigned to receive 5 mg/day tamoxifen (n=253) or placebo (n=247) for 3 years.
    • Funding: Italian Ministry of Health; Italian Association for Cancer Research; Italian League Against Cancer.
    • Dr DeCensi reports research funding from Indena SpA, Roche, Pfizer, Janssen, Novartis, Sanofi Aventis, Quintiles, Gilead, and Macrogenics.

    Limitations

    • Few CBC events.
    • 69%-70% DCIS.