Randomized trial comparing conventional vs short-course reduced volume conformal post-surgery radiation treatment in women with stage I or II breast cancer

Background and objectives:

Tomotherapy is a radiation therapy system that uses an integrated CT scan to improve the accuracy of the radiation dose delivery. Furthermore, the irradiation is delivered helicoidally resulting in high conformal dose distributions. However, the magnitude of the clinical advantage of this system in breast cancer is unknown. The purpose of the present study is investigating whether the Tomotherapy Hi-ART II system can substantially reduce pulmonary and cardiac toxicities, as compared to conventional radiotherapy.

Inclusion criteria:

Histologically proven invasive breast carcinoma
Stage I or II (T1-3N0 or T1-2N1 M0, AJCC/TNM 6th edition)
Women > 18 years old
Surgery with clear margins
Pre-operative medical imaging

Study plan:

Arm I: conventional radiotherapy using 2 tangential chest fields, and a supraclavicular field in case of nodal involvement. Dose-fractionation: 50 Gy in 25 fractions over 5 weeks. Additional boost 16 Gy in 8 fractions over 2 weeks if breast conserving surgery.
Arm II: radiotherapy using the Tomotherapy system. Target volumes (breast, thoracic wall, nodal areas if N+) are delineated according to pre-operative imaging and pathological description. Dose-fractionation: 42 Gy in 15 fractions over 3 weeks. Simultaneous boost 0.6 Gy/fraction to the tumorbed if breast conserving surgery.