[Accelerated partial breast irradiation: bifractionated 40Gy in one week. A French pilot phase II study].
OBJECTIVE
Since 2009, accelerated partial breast irradiation (APBI) in North America has been allowed to be used for selected group of patients outside a clinical trial according to the ASTRO consensus statement. In France, accelerated partial breast irradiation is still considered investigational, several clinical trials have been conducted using either intraoperative (Montpellier) or Mammosite(®) (Lille) or brachytherapy modality (PAC GERICO/FNCLCC). Here, we report the original dosimetric results of this technique.


METHODS
Since October 2007, Institut Gustave-Roussy has initiated a phase II trial using 3D-conformal accelerated partial breast irradiation (40 Gy in 10 fractions BID in 1 week). Twenty-five patients with pT1N0 breast cancer were enrolled and were treated by two minitangent photons beams (6MV) and an "en face" electron beam (6-22 MeV).


RESULTS
The mean clinical target volume and planning target volume were respectively 15.1cm(3) (range: 5.2-28.7 cm(3)) and 117 cm(3) (range: 52-185 cm(3)). The planning target volume coverage was adequate with at least a mean of 99% of the volume encompassed by the isodose 40 Gy. The mean dose to the planning target volume was 41.8 Gy (range: 41-42.4 Gy). Dose inhomogeneity did not exceed 5%. Mean doses to the ipsilateral lung and heart were 1.6 Gy (range: 1.0-2.3 Gy) and 1.2 Gy (range: 1.0-1.6 Gy), respectively.


CONCLUSIONS
The 3D conformal accelerated partial breast irradiation using two minitangent and "en face" electron beams using a total dose of 40 Gy in 10 fractions BID over 5 days achieves appropriate planning target volume coverage and offers significant normal-tissue sparing (heart, lung). Longer follow-up is needed to evaluate the tissue tolerance to this radiation dose.
Bourgier
C
C
Département d'oncologie-radiothérapie, institut Gustave-Roussy, 39, rue Camille-Desmoulins, 94800 Villejuif, France. bourgier@igr.fr
Pichenot
C
C
Verstraet
R
R
Heymann
S
S
Biron
B
B
Balleyguier
C
C
Delaloge
S
S
Mathieu
M-C
MC
Uzan
C
C
Garbay
J-R
JR
Bourhis
J
J
Taghian
A
A
Marsiglia
H
H
D000368:Aged; D001071:Appointments and Schedules; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D019583:Dose Fractionation, Radiation; D004583:Electrons / Q000627:therapeutic use; D005260:Female; D005602:France; D006321:Heart / Q000528:radiation effects; D006801:Humans; D008168:Lung / Q000528:radiation effects; D015412:Mastectomy, Segmental; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D017785:Photons / Q000627:therapeutic use; D010865:Pilot Projects; D017698:Postmenopause; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000379:methods*