Dose Escalated Concomitant Boost Radiotherapy for Early Breast Cancer

This is a prospective, single-arm, phase II, non-randomized clinical trial that will test an hypofractionated schedule with high dose simultaneous integrated tumor bed boost set on a previous dose finding study. Patients will be treated with hypofractionated RT to whole breast with a dose of 40.05 Gy in 15 fractions (2.67 Gy/die) and a concomitant tumor bed dose of 52.5 Gy (3.5 gy/die). The study population will include early breast cancer patients with younger age (< or= 50 years) and additional risk factors for local recurrence.

The primary objective of the study is to evaluate the rate of radiation-induced fibrosis at 4 years.The expected enrollment is 132 patients in 6 years. Each patient must have a minimum follow-up of 4 years.

The secondary objective is to evaluate cosmesis; other objectives are to evaluate quality of life (QoL) and the rate of local control.

Inclusion criteria

• histologically proven breast cancer who have undergone conservative surgery
• at least 3 inserted clips
• age: from 18 years old to 50 years
• at least one of the following risk factors: N1 disease, LVI, extensive intraductal component (>25%), close margins (<4 mm), non-hormone-sensitive disease, grading 3
• ECOG performance status < 2
• adequate bone marrow (haemoglobin concentration > 8 g/dl, white blood cell count > 3000/mm3, platelet count > 75000).

Exclusion criteria

• Previous chest radiation treatment
• Bilateral breast cancer
• Neoadjuvant chemotherapy
• BMI > 35
• Collagen diseases
• Pregnancy or breastfeeding