The treatment outcomes were reviewed for all the patients at this institute
who underwent breast irradiation after breast conserving surgery in 1991.
Of a total of 643 patients treated, 194 (30%) had presented with tumours de
tected by screening mammography. The breast was irradiated with a tangentia
l pair of fields, giving a dose of 40 Gy in 15 fractions over 3 weeks in 97
% of these patients. A boost was not used. With a median follow-up of 4.7 y
ears, there was better cancer related survival in patients with screen dete
cted cancers compared with those that were non-screen detected (94% versus
84% at 5 years; P = 0.002). The breast recurrence rate at 5 years was 1% fo
r screen detected cancers compared with 6% for those that were non-screen d
etected (P = 0.01). Factors additional to screen detected status that were
found to be significant for cancer survival were pathological stage (P = 0.
03) and histological grade (P = 0.01), In a Cox multivariate analysis, only
two factors were significant for breast recurrence: screen detected status
(P = 0.023) and histological grade (P = 0.016)
This study suggests that breast irradiation with 40 Gy given over 3 weeks a
fter breast conserving surgery for screen detected breast cancer gives a hi
gh level of local control out to 5 years.