Impact of a breathing-control system on target margins and normal-tissue sparing in the treatment of lung cancer: experience at the radiotherapy unit of Florence University.
OBJECTIVE
In lung cancer, a high radiation dose to the target area correlates with better local control but is frequently counterbalanced by a higher risk of lung toxicity. Several methods exist to coordinate respiratory motion in lung radiotherapy. We aimed to investigate the impact of a breathing-control system on irradiated volumes and dosimetric parameters in three-dimensional conformal radiotherapy (3D-CRT) and stereotactic radiotherapy (SRT) treatments.


METHODS
Twelve patients were scheduled for radical radiotherapy: five for SRT and seven for 3D-CRT. For each patient, in addition to the free-breathing computed tomography (CT) scan, four additional sets of CT slices were acquired using the Active Breathing Coordinator device (ABC, Elekta Oncology Systems Ltd., UK).


RESULTS
The volumes acquired with the ABC device were significantly smaller than the free-breathing volumes [23 % reduction of planning tumour volume (PTV), p = 0.002]. ABC allowed a reduction of all dosimetric parameters [2.28 % reduction of percentage volume of lung treated to a dose of ≥ 20 Gy (V20), p = 0.004; 10 % reduction of mean lung dose (MLD), p = 0.009]. Significant differences were found both in SRT and in 3D-CRT, in peripheral and apical lesions.


CONCLUSIONS
In our experience, ABC has the potential to reduce lung toxicity in the treatment of lung cancer; alternatively, it can allow the prescribed dose to be increased while maintaining the same risk of lung toxicity.
Department of Radiation Oncology, University of Florence, Viale Morgagni 85, 50134, Florence, Italy, v.scotti@dfc.unifi.it.
Vieri
V
Scotti
Livia
L
Marrazzo
Calogero
C
Saieva
Benedetta
B
Agresti
Icro
I
Meattini
Isacco
I
Desideri
Sara
S
Cecchini
Silvia
S
Bertocci
Ciro
C
Franzese
Carla
C
De Luca Cardillo
Giacomo
G
Zei
Mauro
M
Loi
Daniela
D
Greto
Monica
M
Mangoni
Pieroluigi
P
Bonomo
Lorenzo
L
Livi
Gian Paolo
GP
Biti
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007558:Italy; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009068:Movement; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012119:Respiration; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden