Clinical trial · Observational
Long-term Follow-up of the TAM-01 Study and Pooled Analysis of Low-dose Tamoxifen Studies in Non-invasive or Microinvasive Breast Neoplasms
Long-term Follow-up of the TAM-01 Study, a Phase III Trial of Low-dose Tamoxifen, and Pooled Analysis of Three Studies in Breast DCIS, High-risk Lesions and Microinvasive Disease
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
Low-dose tamoxifen (5 mg/day for three years, BabyTam) has emerged as a safer and effective alternative to the standard regimen (20 mg/day), reducing breast cancer recurrence with fewer adverse events. The TAM-01 phase III trial demonstrated a 42% reduction in breast cancer events over ten years compared to placebo in women with ductal carcinoma in situ (DCIS) or high-risk lesions (HRL, ADH, LCIS), supporting its inclusion in clinical guidelines. The phase III TAM-01 trial enrolled 500 women, comparing low-dose tamoxifen to placebo over three years, with a median follow-up of 9.7 years (IQR, 8.3-10.9). Results showed a significant reduction in invasive breast cancer (HR = 0.58; 95% CI: 0.35-0.95; p = 0.03) and in contralateral breast cancer, CBC (HR = 0.36; 95% CI: 0.14-0.92; p = 0.025), with no increase in serious adverse events. Exploratory analyses suggested a greater benefit in postmenopausal women (HR = 0.30; 95% CI: 0.11-0.82), compared to premenopausal women (HR = 0.73; 95% CI: 0.30-1.76), though this interaction did not reach statistical significance (p-interaction = 0.13). However, our unpublished data indicate a remarkable reduction of CBC in premenopausal women on BabyTam. The TAM-01 long-term follow-up study aims to extend the follow-up of TAM-01 participants, evaluating long-term outcomes, including incidence of invasive breast cancer and DCIS, with a focus on tumor laterality and menopausal status, as well as to assess other non-invasive events (LCIS, ADH, or ALH) and adverse outcomes of special interest. We will also perform a pooled analysis of our three low-dose tamoxifen studies to increase the statistical power of our findings, with special attention to the effect according to menopausal status and site of recurrence. The primary endpoint will be the breast cancer-free interval. The findings are expected to strengthen the evidence supporting low-dose tamoxifen as a viable prevention strategy in high-risk populations with intraepithelial neoplasia (IEN or DCIS+HRLs) or microinvasive disease.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer Invasive | — | UNRESOLVED | — |
Interventions
Interventions (2)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Tamoxifen (Nolvadex) | Drug | Tamoxifen | ALIAS |
| Tamoxifen (Nolvadex) placebo | Drug | — | UNRESOLVED |
Design
Arms and outcomes
Arms (2)
- label
- Tamoxifen
- description
- All women received one tablet of tamoxifen 5 mg per day for 3 years during the TAM-01 phase III trial.
- interventionNames
- Drug: Tamoxifen (Nolvadex)
- label
- Placebo
- description
- All women received one tablet of placebo per day for 3 years during the TAM-01 phase III trial.
- interventionNames
- Drug: Tamoxifen (Nolvadex) placebo
Primary outcomes (2)
- measure
- Incidence of invasive breast cancer and breast cancer-free interval
- timeFrame
- Each patient will be followed for a total period of 20 years from the date of randomization in the TAM-01 trial, with data collected and updated annually.
- description
- The primary objective is to compare the incidence of invasive breast cancer and ductal carcinoma in situ in a long-term follow-up of the TAM-01 study and to compare the breast cancer-free interval among the three low-dose tamoxifen studies.
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion criteria: * Women with DCIS or high-risk lesions or pT1aN0 breast cancer previously enrolled in the TAM-01 trial (EudraCT number: 2007-007740-10) and in the IEO-S007 trial and the prospective cohort study. * Written informed consent. Exclusion criteria: * None.
References
Publications (1)
- DERIVEDGandini S, Guerrieri-Gonzaga A, Serrano D, Rizzo R, Lazzeroni M, Puntoni M, Buttiron Webber T, Aurilio G, Johansson H, Carbone A, Giordano L, Digennaro M, Cortesi L, Millo F, Cagossi K, Aprile G, Serra P, Gallerani E, Debiasi M, Sousa B, Gouveia P, Bonanni B, DeCensi A. Low-Dose Tamoxifen in Noninvasive Breast Neoplasia: Long-Term Results From an Individual-Participant Data Pooled Analysis. J Clin Oncol. 2026 Aug;44(22):2121-2129. doi: 10.1200/JCO-26-00841. Epub 2026 May 31. PMID 42218652