NCT04046159

Radiotherapy Versus Low-Dose Tamoxifen Following Breast Conserving Surgery for Low-Risk Breast Ductal Carcinoma in Situ

Status unknown Phase 3 Last updated 6 August 2019

What this trial tests

Phase 3 trial testing Low-dose tamoxifen in Breast Ductal Carcinoma in Situ in 810 participants. Status unknown.

Timeline

30 April 2019

Primary endpoint
31 December 2025

31 December 2025

Quick facts

Lead sponsor	National Taiwan University Hospital
Phase	Phase 3
Status	Status unknown
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	none
Primary purpose	treatment
Enrollment	810
Start date	30 April 2019
Primary completion	31 December 2025
Estimated completion	31 December 2025
Sites	1 location across Taiwan

Drugs / interventions tested

• Low-dose tamoxifen — full drug profile →
• Whole breast radiotherapy

Conditions studied

• Breast Ductal Carcinoma in Situ — all drugs for Breast Ductal Carcinoma in Situ →

Sponsor

National Taiwan University Hospital

Who can join

40 and older, female only, with Breast Ductal Carcinoma in Situ. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

Although the results obtained from ECOG E5194 cohort 1 (criteria: mammographically detected low- or intermediate-grade DCIS, measuring less than 2.5 cm with margins ≥ 3 mm) and RTOG 9804 trial (the same enrolled clinicopathological features to cohort 1 of ECOG E5194 trial) demonstrated that the 7-year ipsilateral breast tumor recurrence (IBTR) ranged from 5.6% to 10.5% for low-risk ductal carcinoma in situ (DCIS) patients, the aforementioned two studies included a proportional patients who had young age and negative estrogen receptor (ER) status tumor. Previous studies and our studies revealed that age \< 40 years and ER-negative status in tumor were independent prognostic factor for recurrence of breast DCIS irrespective of tumor characteristics. The UK/ANZ randomized trial, enrolling high-risk and low-risk clinicopathologic features of DCIS, demonstrated that a benefit of tamoxifen in terms of reducing the IBTR is observed in the BCS alone group but not found in the BCS plus RT group. A recent published randomized trial showed that tamoxifen at the dose of 5 mg/day for 3 years.

Based on the aforementioned results, we hypothesized that the administration of tamoxifen is not inferior than the prescription of RT in terms of reducing the IBTR for DCIS patients who had age more than 40 years, the pathological features meeting the ECOG E5194 cohort 1 criteria, and positive ER status in tumors. To approve the hypothesis, we will design a randomized non-inferiority trial to assess whether the effect of administration of tamoxfien (5 mg per day) for 10 years following BCS is not inferior in terms of reducing IBTR when comparing RT following BCS for patients who had low-risk clinicopathologic features (age more than 40 years and ECOG E5194 cohort 1 criteria) and positive-ER status of breast DCIS.

Publications & conference data

4 peer-reviewed publications reference this trial (live from Europe PMC):

1. Radiotherapy versus low-dose tamoxifen following breast-conserving surgery for low-risk and estrogen receptor-positive breast ductal carcinoma in situ: an international open-label randomized non-inferiority trial (TBCC-ARO DCIS Trial).
   Kuo SH, Tseng LM, Chen ST, Sagara Y, et al · · 2023 · cited 6× · PMID 37710198 · DOI 10.1186/s12885-023-11291-6
2. Update on the management of ductal carcinoma in situ of the breast: current approach and future perspectives.
   Kanbayashi C, Iwata H. · · 2025 · cited 3× · PMID 39223698 · DOI 10.1093/jjco/hyae122
3. Adjuvant Radiation vs Endocrine Therapy After Lumpectomy for Early-Stage Breast Cancer in Older Women: Analysis of Real-World Survival Outcomes.
   Nierenberg TC, Crowell KA, Wang T, Rosenberger LH, et al · · 2025 · cited 2× · PMID 40478341 · DOI 10.1245/s10434-025-17532-1
4. Management of Ductal Carcinoma In Situ: An Ontario Health (Cancer Care Ontario) Clinical Practice Guideline.
   Brackstone M, Durocher-Allen L, Califaretti N, Eisen A, et al · · 2024 · cited 1× · PMID 39727692 · DOI 10.3390/curroncol31120569