Ductal carcinoma in situ revisited

Abstract

Since our review appeared in The Breast, further information from randomized studies has become available. The EORTC data have been published and are summarized in Table 1. This was a randomized trial assessing the value of radiotherapy after breast conserving surgery. The results demonstrate a significant advantage for radiotherapy both in terms of ductal carcinoma in situ (DCIS) and invasive recurrence. There was a significant excess of contralateral cancers in the irradiated group. The benefits of radiotherapy in the NSABP study was greatest in patients at high risk of recurrence. Marked/moderate comedo necrosis, solid tumour type, moderate/marked lymphoid infiltrate and multifocality were all found to be significant predictors for breast recurrence in patients treated by wide excision alone or wide local excision plus radiotherapy. Uncertain/involved margins and poor unclear grade were of borderline significance (Table 2). 1 The results relating grade to local recurrence from the EORTC study have been presented but have not been separated into groups who did or did not have radiotherapy but have not shown a relationship between degree of differentiation of DCIS and local recurrence, which is surprising (Table 3). The most recent publication from the NSABP treated patients with DCIS by wide local excision and radiotherapy and randomized them for tamoxifen, 20 mg a day for 5 years. 2 Although this study showed a significant reduction in all breast cancer events there were only significant reductions in ipsilateral invasive disease and contralateral DCIS. Surprisingly there was no apparent effect on ipsilateral DCIS and contralateral invasive cancer (Table 4). The effect of tamoxifen was also much greater in patients whose disease was incompletely excised. The role of tamoxifen in DCIS which has been widely excised remains uncertain