Value of Tamoxifen, Long- Term Radiotherapy Confirmed in DCIS
Enhanced screening efforts have increased the number of patients diagnosed with ductal carcinoma in situ (DCIS). Of the treatment options available, radiotherapy has previously been shown effective in reducing recurrences of in situ or invasive ipsilateral disease. New long-term results from the United Kingdom, Australia, and New Zealand DCIS trial highlight the role of tamoxifen in this patient population (Cuzick J, et al. Lancet Oncol. 2011;12:21-29).
A total of 1701 patients with locally excised DCIS were randomized into a 2×2 factorial trial of radiotherapy, tamoxifen, or both. The primary end points were (1) invasive ipsilateral new events for radiotherapy, and (2) any new breast cancer–related event for tamoxifen.
At a median follow-up of 12.7 (range, 10.9-14.7) years, among the 1694 eligible patients (with ipsilateral or contralateral disease), 163 invasive cancers, 197 DCIS, and 16 cases of unknown invasiveness or laterality disease were diagnosed. The incidence of all new breast cancer–related events was significantly reduced with radiotherapy (P <.001) and with tamoxifen (P = .002); radiotherapy reduced ipsilateral invasive disease and ipsilateral DCIS but had no effect on contralateral breast cancer. Tamoxifen significantly reduced recurrent ipsilateral DCIS and contralateral tumors but not ipsilateral invasive disease.