Phase I-II studies on accelerated IMRT in breast carcinoma: technical comparison and acute toxicity in 332 patients.
OBJECTIVE
To evaluate the results in terms of dosimetric parameters and acute toxicity of two clinical studies (MARA-1 and MARA-2) on accelerated IMRT-based postoperative radiotherapy. These results are compared with historical control group (CG) of patients treated with "standard" 3D postoperative radiotherapy.


METHODS
Prescribed dose to the breast was 50.4Gy in the CG, 40Gy in MARA-1 (low risk of local recurrence), and 50Gy in MARA-2 (medium-high risk of recurrence). The tumor bed total dose was 60.4Gy (sequential 10Gy electron boost), 44Gy (concomitant 4Gy boost), and 60Gy (concomitant 10Gy boost) in CG, MARA-1 and MARA-2 studies, respectively. Overall treatment time was of 32 fractions for CG (6.4weeks); 16 fractions for MARA-1 study (3.2weeks) and 25 fractions for MARA-2 study (5weeks).


RESULTS
Three hundred and thirty two patients were included in the analysis. Dosimetric analysis showed D(max) and V(107%) reduction (p<0.001) and D(min) improvement (p<0.001) in the PTV in patients treated with IMRT. Grade 2 acute skin toxicity was 33.6%, 13.1%, and 45.1% in the CG, MARA-1, and MARA-2, respectively (p<0.001), and grade 3 acute skin toxicity was 3.1%, 1.0%, and 2.0%, respectively. Similarly, larger PTV and use of chemotherapy with anthracyclines and taxanes were associated with a greater acute toxicity. With a median follow-up of 31 months, no patients showed local or nodal relapse.


CONCLUSIONS
A simplified step and shoot IMRT technique allowed better PTV coverage and reduced overall treatment time (CG, 6.6weeks; MARA-1, 3.2weeks; MARA-2, 5weeks) with acceptable short-term toxicity.
Morganti
Alessio G
AG
Department of Radiotherapy, John Paul II Center for High Technology Research and Education in Biomedical Sciences, Campobasso, Italy.
Cilla
Savino
S
Valentini
Vincenzo
V
Digesu'
Cinzia
C
Macchia
Gabriella
G
Deodato
Francesco
F
Ferrandina
Gabriella
G
Cece
M Grazia
MG
Cirocco
Massimo
M
Garganese
Giorgia
G
Di Lullo
Liberato
L
Traficante
Divina
D
Scarabeo
Francesca
F
Panunzi
Simona
S
De Gaetano
Andrea
A
Sallustio
Giuseppina
G
Cellini
Numa
N
Sofo
Luigi
L
Piermattei
Angelo
A
Scambia
Giovanni
G
D000368:Aged; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods*; D016896:Treatment Outcome