5‑fraction whole‑breast radiation with a simultaneous boost versus standard 15‑fraction radiation for younger or unfavorable breast cancer

Five Fractions Ultrahypofractionated Whole Breast Radiotherapy and Simultaneous Integrated Boost to the Tumor Bed, for Breast Cancer Patients With Unfavorable Characteristics

Not applicable Interventional IRCCS San Raffaele · NCT07020780

This will see if a very short 5‑session whole‑breast radiation with a boost to the tumor bed works as well as the standard 15‑session regimen for younger or higher‑risk breast cancer patients after breast‑conserving surgery.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment458 (estimated)
Ages18 Years to 70 Years
SexFemale
SponsorIRCCS San Raffaele Academic / other
Locations1 site (Milan)
Trial IDNCT07020780 on ClinicalTrials.gov

What this trial studies

This is a prospective, randomized, single‑center non‑inferiority trial comparing an ultrahypofractionated schedule (26 Gy in 5 fractions with a simultaneous integrated boost to 30 Gy) to the department’s standard moderately hypofractionated regimen (40.05 Gy in 15 fractions with SIB to 48 Gy). Eligible patients have T1–T3, Nx–N3 disease, underwent breast‑conserving surgery with negative margins, and are either under 40 years or aged 40–70 with unfavorable histology (lobular, Luminal B HER2‑positive, HR‑negative HER2‑positive, or triple‑negative). Radiotherapy may include regional lymph node areas as indicated, and participants are randomized to one of the two schedules for adjuvant whole‑breast irradiation. The trial tests whether the shorter 5‑fraction approach provides comparable local control and safety while offering greater convenience.

Who should consider this trial

Good fit: Ideal candidates are patients with T1–T3, Nx–N3 breast cancer who had breast‑conserving surgery and are younger than 40 or aged 40–70 with unfavorable tumor subtypes (lobular, Luminal B HER2‑positive, HR‑negative HER2‑positive, or triple‑negative).

Not a fit: Patients who had mastectomy, multicentric tumors, positive or very close (<0.2 cm) margins, known BRCA1/2 positivity, or favorable subtypes (Luminal A or Luminal B HER2‑negative) are unlikely to be eligible or to benefit from this approach.

Why it matters

Potential benefit: If successful, patients could complete effective whole‑breast radiation in five visits instead of 15, reducing treatment time and clinic visits while maintaining disease control.

How similar studies have performed: Large trials like FAST‑Forward showed non‑inferiority of 5‑fraction whole‑breast regimens for many patients, but using a simultaneous integrated boost in younger or unfavorable subtypes remains less well studied.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Histological diagnosis of breast cancer
2. Patients younger than 40 years regardless of histological subtype, or patients between 40 and 70 years with lobular carcinoma, histological subtypes Luminal B Her2 positive, or with hormone receptors negative and Her2 positive (ErbB2), or triple negative (TNBC)
3. Signed informed consent
4. Clinical stage T1-T3, Nx-N3
5. Negative surgical margins (≥ 0.2 cm)
6. Clinical M0 in the previous 3 months
7. PS (ECOG) ≤2
8. No previous thoracic radiotherapy
9. Fertile women using contraceptive methods started during oncological treatment

Exclusion Criteria:

1. Patients with favorable characteristics (Luminal A, Luminal B Her2 negative, ≥ 40 years) undergoing partial irradiation
2. Patients who have undergone mastectomy
3. Multicentric tumors
4. Positive or close surgical margins (\<0.2 cm)
5. BRCA1/2 positive (only if known)
6. Serious systemic diseases
7. Mental or other disorders that may prevent the patient from signing the informed consent
8. Previous invasive tumor, except skin cancer (excluding melanoma) unless the patient has been disease-free for at least 3 years (for example carcinoma in situ of the oral cavity or bladder)
9. Collagen or autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, scleroderma, Sjogren's syndrome)
10. Evidence of distant metastases (M1)
11. Contraindication to treatment systemic
12. Pregnant women
13. Non-compliance with the dose limits established in the treatment plan

Where this trial is running

Milan

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast CancerWhole Breast IrradiationSimultaneous Integrated BoostAdjuvant RadiotherapyUtrahypofractionated RadiotherapyModerately Hypofractionated Radiotherapy
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.