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NCT Number: NCT07762924

Omission of Adjuvant Radiotherapy in Young Low-Risk Ductal Carcinoma In Situ Following Breast-Conserving Surgery

This is a single-center, prospective phase II clinical study designed to evaluate whether omission of postoperative radiotherapy is clinically acceptable in young patients with low-risk ductal carcinoma in situ (DCIS) following breast-conserving surgery. Eligible patients include women younger than 40 years with low- or intermediate-grade DCIS, tumor size ≤1 cm, negative surgical margins ≥3 mm, absence of comedo necrosis, and unifocal screen-detected disease. Patients in the radiotherapy omission cohort will undergo close surveillance after surgery, with endocrine therapy permitted according to physician discretion. The primary endpoint is 5-year ipsilateral breast tumor recurrence (IBTR).

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Key information

Conditions

Ductal Carcinoma In Situ, DCIS Adenocarcinoma Breast Carcinoma In Situ Carcinoma Carcinoma in Situ Carcinoma, Intraductal, Noninfiltrating Neoplasms Neoplasms by Histologic Type Neoplasms, Ductal, Lobular, and Medullary Neoplasms, Glandular and Epithelial

Age range

Up to 40 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 2

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Female patients aged <40 years；
  • Histologically confirmed low- or intermediate-grade ductal carcinoma in situ (DCIS) without invasive carcinoma, including incidental DCIS identified within benign breast lesions；
  • Tumor size ≤1 cm on final pathology；
  • Negative surgical margins ≥3 mm, including margins obtained after re-excision；
  • Unifocal lesion；
  • Absence of comedo necrosis；
  • Screen-detected disease without bloody nipple discharge or palpable mass；
  • Clinically node-negative disease；
  • Central pathology review by the participating institution required；
  • Ability to understand and willingness to sign written informed consent.

Exclusion criteria

  • Known BRCA1, BRCA2, or TP53 germline mutation carriers (genetic testing not mandatory)；
  • Bilateral breast cancer or prior contralateral breast cancer；
  • Severe uncontrolled comorbidities, including significant cardiac, pulmonary, hepatic, renal, hematologic, or psychiatric disorders；
  • History of other malignancies, including thyroid cancer, except adequately treated basal cell carcinoma of the skin or cervical carcinoma in situ；
  • Pregnant or breastfeeding patients；
  • Estimated life expectancy ≤5 years；
  • Poor compliance or inability to adhere to study follow-up requirements.

Treatment and study plan

observation

Other

No postoperative radiotherapy will be administered. Patients will receive close surveillance after surgery.

Endocrine Therapy (Optional)

Drug

Adjuvant endocrine therapy may be administered according to physician discretion and patient preference.

Primary outcomes

  1. Ipsilateral Breast Tumor Recurrence (IBTR)

    Time frame: 5 years

    Defined as recurrence of invasive carcinoma or DCIS in the ipsilateral breast.

Secondary outcomes

  1. Local-Regional Recurrence (LRR)

    Time frame: 5 years

    Defined as recurrence in the ipsilateral breast, chest wall, supraclavicular region, axilla, or internal mammary region.

  2. Breast Cancer-Specific Survival (BCSS)

    Time frame: 5 years

    Defined as time from study enrollment to death due to breast cancer.

  3. Overall Survival (OS)

    Time frame: 5 years

    Defined as time from study enrollment to death from any cause.

  4. Distant Metastasis-Free Survival (DMFS)

    Time frame: 5 years

    Distant Metastasis defined as recurrence outside local-regional sites.

  5. Contralateral Breast Cancer Events

    Time frame: 5 years

    Defined as participants diagnosed with a new primary breast cancer in the contralateral breast. Diagnosis will be confirmed by pathological examination.

  6. Mastectomy-Free Survival

    Time frame: 5 years

    Defined as participants who are alive and have not undergone mastectomy of the treated breast after initiation of study treatment.

  7. Second Primary Malignancies

    Time frame: 5 years

    Defined as participants diagnosed with a new primary malignancy, excluding recurrence or metastasis of the index breast cancer.

  8. Quality-of-Life Assessed by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)

    Time frame: 5 years

    Global health quality of life is assessed using the EORTC QLQ-C30. Scores are transformed to a 0-100 scale, with higher scores indicating better global health status and quality of life. Change from baseline will be evaluated during follow-up.

  9. Quality-of-Life Assessed by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module 23 (EORTC QLQ-BR23)

    Time frame: 5 years

    Breast cancer-specific symptom burden is assessed using the EORTC QLQ-BR23. Scores are transformed to a 0-100 scale. Change from baseline will be evaluated during follow-up.

  10. Anxiety Assessment

    Time frame: 5 years

    Change from baseline in anxiety symptoms assessed using a validated patient-reported anxiety assessment instrument.

  11. Patient-Reported Outcomes

    Time frame: 5 years

    Change from Baseline in Patient-reported Treatment-related Symptoms Assessed by PRO-CTCAE.

Other outcomes

  1. Tumor-Infiltrating CD8-Positive T-Cell Density

    Time frame: Baseline

    Density of tumor-infiltrating CD8-positive T cells in pretreatment tumor tissue, assessed by IHC or mIF.

  2. Tumor PD-L1 Expression

    Time frame: Baseline

    PD-L1 expression in pretreatment tumor tissue assessed by IHC and quantified using the Combined Positive Score (CPS).

Study contacts

Contact information is provided by the study sponsor or research team.

Jin Meng

CONTACT

[email protected]

+86 18121299532

Xiaoli Yu

CONTACT

[email protected]

+86-021-64175590

Sponsors and collaborators

Lead sponsor

Fudan University

Other

Registry information

Official study title

A Single-Center Prospective Phase II Study Evaluating the Safety of Omission of Adjuvant Radiotherapy in Young Patients With Low-Risk Ductal Carcinoma In Situ After Breast-Conserving Surgery

Important dates

Study start
2026
Primary completion
2032
Study completion
2037
First posted
Aug 13, 2026
Registry last updated
Aug 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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