Post-operative radiotherapy for ductal carcinoma in situ of the breast – A systematic review of the randomised trials

To summarise the results of randomised trials testing the addition of radiotherapy (RT) to breast conserving surgery for ductal carcinoma in situ (DCIS); to determine whether there are subsets of women with DCIS who do not benefit from RT; and to determine what the balance may be between reduction in risk of recurrence and long-term toxicity.We performed a systematic review to resolve these questions, using standard Cochrane methodology to identify, select and appraise relevant randomised trials.Four randomised controlled trials involving 3925 women were identified. All were high quality with minimal risk of bias. Analysis confirmed a statistically significant benefit from the addition of radiotherapy on all ipsilateral breast events (HR=0.49; 95% CI 0.41-0.58, p0.00001). All subgroups analysed (margin status, age and grade) benefited from the addition of radiotherapy. Nine women require treatment with radiotherapy to prevent one ipsilateral breast recurrence (NNT=9). Deaths due to vascular disease, pulmonary toxicity and second cancers were low and not significantly higher for women who received radiotherapy.Radiotherapy was beneficial in all clinically relevant subgroups. Longer follow-up is required to detect any long-term toxicity from use of radiotherapy. To date, no increase in toxicity has been identified.