Could some breast cancer patients skip radiation entirely?

NCT ID NCT07762885

Disease control Sponsor: Fudan University Source: ClinicalTrials.gov ↗

First seen Aug 13, 2026 · Last updated Aug 14, 2026 · Updated 1 time

Summary

This trial is asking whether women with a very early, non-invasive breast condition called ductal carcinoma in situ (DCIS) can safely skip radiation therapy after having breast-conserving surgery. The study focuses on women aged 40 and older with low- or intermediate-risk DCIS that is estrogen receptor-positive, small (≤2.5 cm), and has clear margins. Participants are randomly assigned to either receive standard radiation or no radiation, with all taking tamoxifen. The main goal is to see if skipping radiation leads to a similar rate of the cancer returning in the same breast within five years.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: Adjuvant radiotherapy (partial or whole breast irradiation) versus observation alone, with tamoxifen as background endocrine therapy
What this could lead to: If skipping radiation proves safe, many women with low-risk DCIS could avoid weeks of daily treatment and its side effects, without raising their risk of the cancer coming back.
What could go wrong: This is a non-inferiority trial, so it can only show that omitting radiation is not much worse than having it—not that it's better. The results may not apply to women with higher-risk features, and there is still a small chance that skipping radiation increases recurrence risk.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

About 636 people

The number the study aims to enrol. It can still change while the study runs.

Started

Jul 2026

Expected to finish

Jun 2036

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

40 years and older

Sex

Female participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Female patients aged ≥40 years； 2. Histologically confirmed low- or intermediate-grade ductal carcinoma in situ (DCIS) without invasive carcinoma, including incidental DCIS identified within benign breast lesions； 3. Tumor size ≤2.5 cm on final pathology； 4. Negative surgical margins ≥3 mm, including margins obtained after re-excision； 5. Estrogen receptor-positive disease (ER ≥10%) with planned endocrine therapy using tamoxifen； 6. Unifocal lesion； 7. Absence of comedo necrosis； 8. Screen-detected disease without bloody nipple discharge or palpable mass； 9. Clinically node-negative disease； 10. Patients randomized to the radiotherapy arm must initiate radiotherapy within 3 months after surgery； 11. Central pathology review by the participating institution required； 12. Ability to understand and willingness to sign written informed consent. Exclusion Criteria: 1. Known BRCA1 or BRCA2 germline mutation carriers (genetic testing not mandatory)； 2. Contraindications to radiotherapy, including active connective tissue disease； 3. Active infection requiring systemic treatment； 4. Bilateral breast cancer or prior contralateral breast cancer； 5. Severe uncontrolled comorbidities, including significant cardiac, pulmonary, hepatic, renal, hematologic, or psychiatric disorders； 6. History of other malignancies, including thyroid cancer, except adequately treated basal cell carcinoma of the skin or cervical carcinoma in situ； 7. Prior thoracic radiotherapy； 8. Pregnant or breastfeeding patients； 9. Estimated life expectancy ≤5 years； 10. Poor compliance or inability to adhere to study follow-up requirements.

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Conditions

The condition(s) this trial relates to.

ductal breast carcinoma in situ

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Ductal carcinoma in situ, dcis

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

1 site. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

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A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Could some breast cancer patients skip radiation entirely?

What the study statuses mean