Table 4.

Prospective randomized phase III trials of whole breast radiotherapy vs conventional fractionation radiotherapy

Institution/trial	N	Median F/U	Eligibility criteria	Treatment arms	Primary endpoint	Secondary endpoint
Royal Marsden Hospital/Sutton and Gloucestershire Oncology Centre[90,91]	1410	5 yr1	Invasive breast cancer, T1-3N0-1M0, < 75 yr, BCS (complete macroscopic resection),Level II/III AD	50 Gy in 25 fx 39 Gy in 13 fx 42.9 Gy in 13 fx	Late changes in breast appearance	Palpable breast induration Ipsilateral tumor recurrence
UK START A[92,94]	2236	9.3 yr	Invasive breast cancer, T1-3aN0-1M0, > 18 yr, Clear tm margins (≥ 1 mm), No immediate surgical reconstruction, Available for follow-up	50 Gy in 25 fx 41.6 Gy in 13 fx 39 Gy in 13 fx	Loco-regional tumor recurrence	Late normal tissue effects QOL
UK START B[93,94]	2215	9.9 yr	Invasive breast cancer, T1-3aN0-1M0,> 18 yr, Clear tm margins (≥ 1 mm), No immediate surgical reconstruction, Available for follow-up	50 Gy in 25 fx 40 Gy in 15 fx	Loco-regional tumor recurrence	Late normal tissue effects QOL
Ontario Clinical Oncology Group[95]	1234	12 yr	Invasive breast cancer, BCS + Level I/II AD,Tm ≤ 5 cm, Negative axillary nodes, Maximum width of breast tissue ≤ 25 cm, No multicentric disease	50 Gy in 25 fx 42.5 Gy in 16 fx	Local recurrence	Regional and distant recurrence Second cancers Breast cosmesis Late toxic effects of radiation

¹Minimum follow-up. N: Number of patients; F/U: Follow-up; WBRT: Whole breast radiotherapy; RT: Radiotherapy; BCS: Breast conserving surgery; AD: Axillary dissection; fx: Fraction; Gy: Gray; UK START; United Kingdom Standardization of Breast Radiotherapy; QOL: Quality of life.