5 fr Ultrahypofractionated WBI and SIB for Breast Cancer With Unfavorable Characteristics

San Donato Group (GSD)

Status: Begins enrollment this month

Conditions: Breast Cancer

Treatments: Radiation: Adjuvant 5 fractions whole breast irradiation with simultaneous integrated boost to the tumor bed

Study type: Interventional

Funder types: Other

Identifiers

NCT07020780

HY FIVE

Details and patient eligibility

About

This is a prospective, randomized, single-center, non-inferiority interventional clinical trial comparing whole breast irradiation (WBI) to a total dose of 26 Gy in 5 fractions with simultaneous integrated boost (SIB) to the tumor bed to a total dose of 30 Gy, and WBI to a total dose of 40.05 Gy in 15 fractions with SIB to the tumor bed to a total dose of 48 Gy (standard treatment), for young or unfavorable breast cancer patients.

Full description

The project refers to a study on patients with T1-T3 Nx-N3 breast cancer, aged under 40 years or with unfavorable histology (lobular carcinoma, multifocal tumor, or histological subtypes Luminal B Her2 positive, Hormonal Receptors negative Her 2 positive, Triple Negative Breast Cancer-TNBC-) treated with breast-conserving surgery (BCS) and radiotherapy to the whole breast (+/- lymph node areas) to a total dose of 26 Gy in 5 fractions, with simultaneous boost (SIB) to the tumor bed to the total dose of 30 Gy, that will be compared with the current departmental standard of moderately hypofractionated radiotherapy to the whole breast, to 40.05 Gy in 15 fractions, with SIB to the tumor bed to a total dose of 48 Gy.

Enrollment: 458 estimated patients

Sex: Female

Ages: 18 to 70 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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458 participants in 2 patient groups

Arm 1- Five fractions radiotherapy

Experimental group

Description:

Patients in the study (randomized to arm 1) will be treated to the whole breast to a total dose (TD) of 26 Gy in 5 fractions, with simultaneous integrated boost (SIB) to a TD of 30 Gy to the tumor bed. For each patient, an IMRT (intensity modulated radiotherapy) treatment plan will be created to ensure adequate coverage of the treatment volumes and the tolerability of the Organs At Risk (OAR). Specific, already validated dose-volume constraints will be applied for the evaluation of OARs. The dose-volume histogram (DVH) for the Gross Tumor Volume (GTV), Clinical Target Volume (CTV), PTV, and OAR will be calculated in order to achieve the best optimization in terms of tolerability and efficacy.

Treatment:

Radiation: Adjuvant 5 fractions whole breast irradiation with simultaneous integrated boost to the tumor bed

Arm 2- Fifteen fractions radiotherapy

Active Comparator group

Description:

Patients randomized to arm 2 will be treated according to the standard protocol of our department, delivering adjuvant whole breast irradiation (WBI) to a total dose (TD) of 40.05 Gy in 15 fractions, with simultaneous integrated boost (SIB) to the tumor bed to a TD of 48 Gy.

Treatment:

Radiation: Adjuvant 5 fractions whole breast irradiation with simultaneous integrated boost to the tumor bed