Three-year outcomes of a Canadian multicenter study of accelerated partial breast irradiation using conformal radiation therapy.
OBJECTIVE
To report 3-year toxicity, cosmesis, and efficacy of a multicenter study of external beam, accelerated partial breast irradiation (APBI) for early-stage breast cancer.


METHODS
Between March 2005 and August 2006, 127 women aged ≥40 years with ductal carcinoma in situ or node-negative invasive breast cancer ≤3 cm in diameter, treated with breast-conserving surgery achieving negative margins, were accrued to a prospective study involving five Canadian cancer centers. Women meeting predefined dose constraints were treated with APBI using 3 to 5 photon beams, delivering 35 to 38.5 Gy in 10 fractions, twice a day, over 1 week. Patients were assessed for treatment-related toxicities, cosmesis, and efficacy before APBI and at specified time points for as long as 3 years after APBI.


RESULTS
104 women had planning computed tomography scans showing visible seromas, met dosimetric constraints, and were treated with APBI to doses of 35 Gy (n=9), 36 Gy (n=33), or 38.5 Gy (n=62). Eighty-seven patients were evaluated with minimum 3-year follow-up after APBI. Radiation dermatitis, breast edema, breast induration, and fatigue decreased from baseline levels or stabilized by the 3-year follow-up. Hypopigmentation, hyperpigmentation, breast pain, and telangiectasia slightly increased from baseline levels. Most toxicities at 3 years were Grade 1. Only 1 patient had a Grade 3 toxicity with telangiectasia in a skin fold inside the 95% isodose. Cosmesis was good to excellent in 86% (89/104) of women at baseline and 82% (70/85) at 3 years. The 3-year disease-free survival was 97%, with only one local recurrence that occurred in a different quadrant away from the treated site and two distant recurrences.


CONCLUSIONS
At 3 years, toxicity and cosmesis were acceptable, and local control and disease-free survival were excellent, supporting continued accrual to randomized APBI trials.
British Columbia Cancer Agency-Vancouver Island, Victoria, BC, Canada. tberrang@bccancer.bc.ca
Tanya S
TS
Berrang
Ivo
I
Olivotto
Do-Hoon
DH
Kim
Alan
A
Nichol
B C John
BC
Cho
Islam G
IG
Mohamed
Tarnjit
T
Parhar
J R
JR
Wright
Pauline
P
Truong
Scott
S
Tyldesley
Jonathan
J
Sussman
Elaine
E
Wai
Tim
T
Whelan
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002170:Canada; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D017785:Photons / Q000627:therapeutic use; D011446:Prospective Studies; D011832:Radiation Injuries / Q000473:pathology; D011859:Radiography; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D049291:Seroma / Q000000981:diagnostic imaging; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden