One-week versus two-week accelerated breast radiation with a tumor-bed boost

Prospective Randomized Trial of Two Versus One Week Accelerated Radiotherapy (PRATO)

This test compares whether a one-week whole-breast radiation schedule works as well as a two-week schedule with an extra focused boost for women treated with breast-conserving surgery for early breast cancer.

Quick facts

• Phase: Phase 3
• Study type: Interventional
• Enrollment: 400 (estimated)
• Sex: Female
• Sponsor: Weill Medical College of Cornell University (Academic / other)
• Drugs / interventions: chemotherapy, radiation
• Locations: 3 sites (New York, New York and 2 other locations)
• Trial ID: NCT06960707 on ClinicalTrials.gov

What this trial studies

This Phase 3 trial randomly assigns women after lumpectomy for early breast cancer to one of two post‑operative radiation schedules: 26 Gy in 5 fractions delivered over one week or 32 Gy in 10 fractions over two weeks with a concomitant tumor‑bed boost to 36 Gy (if the surgical cavity is visible). The trial tracks acute side effects, long‑term fibrosis, cosmetic outcomes, and local cancer control at 2, 5, and 10 years. Eligibility includes women with negative margins after segmental mastectomy and clinically node‑negative or limited node disease, excluding those with prior ipsilateral breast radiation or certain systemic conditions. Treatments are delivered at participating centers in New York, and imaging and clinical exams are used to monitor toxicity and tumor control.

Who should consider this trial

Good fit: Women who have had breast‑conserving surgery (segmental mastectomy) for early-stage breast cancer with negative margins and clinically node‑negative or limited node involvement are the intended participants.

Not a fit: Patients with prior radiation to the same breast, male breast cancer, prolonged delays from surgery or chemotherapy beyond specified windows, or uncontrolled severe autoimmune disease are unlikely to qualify or benefit from this protocol.

Why it matters

Potential benefit: If successful, the one‑week schedule could offer similar cancer control and cosmetic outcomes with much shorter treatment time and less burden for patients.

How similar studies have performed: The FAST‑FORWARD UK trial showed that a one‑week 26 Gy in 5 fractions regimen was non‑inferior for many patients, but the specific comparison with a two‑week schedule plus concomitant boost is less widely tested and is the focus of this trial.

Eligibility criteria

Inclusion Criteria:

1. Women status post segmental mastectomy.
2. If unilateral, pT1-2 breast cancer excised with negative margins.
3. If bilateral, pT1-2 breast cancer excised with negative margins AND/OR pTis excised with negative margins.
4. Clinically N0 (cN0 as determined by ultrasound/SOUND criteria) or pN0-1 or Nx or sentinel node negative.
5. Ductal carcinoma in situ DCIS with negative margins (no DCIS on inked margins).
6. Women with previous contralateral treated breast cancer can be enrolled in the trial.

Exclusion Criteria:

1. Previous radiation therapy to the ipsilateral breast.
2. \>90 days from last surgery, unless s/p adjuvant chemotherapy.
3. \>60 days from last chemotherapy.
4. Male breast cancer.
5. Ongoing treatment for severe autoimmune disease.

Where this trial is running

New York, New York and 2 other locations

• Brooklyn Methodist Hospital — New York, New York, United States (Recruiting)
• New York Presbyterian Hospital — New York, New York, United States (Recruiting)
• New York-Presbyterian Weill Cornell Medical College — New York, New York, United States (Recruiting)

Study contacts

• Principal investigator: Silvia C. Formenti, MD — Weill Medical College of Cornell University
• Study coordinator: Fabiana Gregucci, MD

Conditions Breast Cancer; Accelerated Radiotherapy; Prone Position; Adjuvant Setting; Non-Inferiority; Concomitant Boost