Postoperative radiotherapy effective for ductal carcinoma in situ of the breast

Clinical question: 
How effective is postoperative radiotherapy (RT) for ductal carcinoma in situ (DCIS) of the breast?
Bottom line: 
The addition of RT following breast conserving surgery (BCS) reduced the risk of recurrence of either DCIS or invasive cancer in the treated breast by 51% (NNT* 9 [8-11]). There was no evidence of increased long term toxicity from the use of RT. Although some trials did not report on the causes of non-breast cancer deaths (deaths which potentially could be related to side effects), the number of non-breast cancer deaths reported was similar in both RT and control groups. *NNT = number needed to treat to benefit one individual (95% confidence interval).
Caveat: 
No information about short-term toxicity from radiotherapy or quality of life data was reported. Clinicians therefore need to ensure that comprehensive information relating to potential side effects is made available to women undergoing this treatment.
Context: 
The addition of RT following BCS was first shown to reduce the risk of ipsilateral recurrence in the treatment of invasive breast cancer. DCIS is a pre-invasive lesion. Recurrence of ipsilateral disease following BCS can be either DCIS or invasive breast cancer. Randomised controlled trials (RCTs) have shown that RT can reduce the risk of recurrence, but assessment of potential long-term complications from the addition of RT following BCS for DCIS has not been reported for women participating in RCTs.
Review CD#: 
CD000563
PEARLS No: 
188
Date: 
August, 2009
Authored by: 
Brian R McAvoy