Accelerated partial breast irradiation: Past, present, and future

Table 4 Phase III prospective randomized trials evaluating the equivalence or non-inferiority of accelerated partial breast irradiation with whole-breast irradiation

Trial	No. of patients	Follow-up interval (yr)	Inclusion criteria	APBI technique	5-yr LR APBI vs WBI (%)
TARGIT-A[45]	3451	2.4	Age ≥ 45 yr; T1, small T2, N0, N1; ductal; non-lobular and no EIC	20 Gy in 1 fraction, IORT low energy X-rays (50 kV)	3.3 vs 1.3
ELIOT[47]	1305	5.8	Age ≥ 48 yr; T ≤ 2.5 cm, N0; invasive carcinoma; quadrantectomy	21 Gy in 1 fraction, IORT, electrons up to 9 MeV	4.4 vs 0.4
RAPID (OCOG)[41]	2135	Pending	Age > 40 yr; T ≤ 3 cm, N0; DCIS or invasive carcinoma; negative margins	38.5 Gy in 10 fractions (5-8 d) using 3D-CRT	Pending
GEC-ESTRO[35]	1184	5.0	Age ≥ 40 yr; T ≤ 3 cm, pN0-Nmi; stage 0, I, II; DCIS, ductal or lobular carcinoma; margin ≥ 2 mm	32 Gy in 8 fractions or 30.3 Gy in 7 fractions MIB HDR or 50 Gy MIB PDR (1 pulse/h, 24 h/d; 0.6-0.8 Gy/h)	1.4 vs 0.9
Florence (NCT02104895)[42]	520	5.0	Age > 40 yr; T < 2.5 cm; clear margins > 5 mm	IMRT 30 Gy in 5 daily fractions	1.5 vs 1.5
IMPORT-LOW	2018	Pending	Age ≥ 50 yr; T ≤ 3 cm, node negative; invasive adenocarcinoma; margin ≥ 2 mm	IMRT; Arm 1: 40 Gy in 15 fractions to primary tumor region + 36 Gy in 15 fractions to low-risk region (EBRT) Arm 2: 40 Gy in 15 fractions to primary tumor region (EBRT)	Pending
IRMA (NCT01803958)	3302 (Currently Enrolling)	Pending	Age ≥ 49 yr; T < 3 cm, N0; invasive carcinoma; margins ≥ 2 mm	38.5 Gy in 10 fractions using 3D-CRT, BID	Pending
SHARE (NCT01247233)	1006	Pending	Age ≥ 50 yr; invasive carcinoma; T ≤ 2 cm; margin≥ 2 mm; pN0 (i+/-)	3D-CRT 40 Gy in 10 fractions, BID	Pending
NSABP B-39/RTOG 0413	4300	Pending	Age ≥ 18 yr; DCIS or invasive adenocarcinoma; stage 0, I, II (T < 3 cm); lumpectomy; margins free of tumor; ≤ 3 positive nodes	34 Gy in 10 fractions using MIB or MammoSite®/MammoSite® ML/SAVI® or 38.5 Gy over 10 fractions using 3D-CRT	Pending

3D-CRT: 3D conformal external-beam radiation; BID: Twice daily; DCIS: Ductal carcinoma in situ; EBRT: External beam radiation therapy; EIC: Extensive intraductal component; HDR: High-dose rate; MIB: Multicatheter interstitial brachytherapy; ML: Multilumen; IMRT: Intensity modulated radiotherapy; IORT: Intraoperative radiotherapy; PDR: Pulsed-dose rate; WBI: Whole-breast irradiation.