Histopathological and cell biological characteristics of ductal carcinoma in situ (DCIS) of the breast-a comparison between the primary DCIS and subsequent ipsilateral and contralateral tumours.

The rate of ipsilateral local recurrence after ductal carcinoma in situ (DCIS) varies (between 5% and 30%) and depends on the type of operation (mastectomy vs. breast-conserving operation), and whether postoperative radiotherapy has been used. Ipsilateral local recurrence can either emanate from the primary lesion or be a new primary tumour. Contralateral lesions may also develop after DCIS. We compared histopathological and cell biological characteristics in 37 subsequent ipsilateral tumours (25 DCIS and 12 invasive cancers) and 13 subsequent contralateral invasive breast cancers with their corresponding primary DCIS. The histopathological parameters were re-evaluated and the cell biological factors were analysed using conventional immunohistochemical techniques in paraffin-embedded material. The concordance rate for high grade (nuclear grade 3) vs. non-high grade (nuclear grades 1+2) between the primary DCIS and the subsequent ipsilateral tumour was higher than between the primary DCIS and the subsequent contralateral invasive cancer (68% vs. 31%). Similar patterns in the concordance rates between the primary DCIS and ipsilateral vs. contralateral tumours were also found in the oestrogen receptor status (83% vs. 50%) and the progesterone receptor status (87% vs. 58%). The pattern persisted in the other factors examined (p53, c-erbB2, bcl-2 and Ki67), although it was less pronounced. The overall high rate of concordance in the characteristics between the primary DCIS and the subsequent ipsilateral tumours suggests that, in most cases, they represent true local recurrences. Subsequent contralateral tumours are more likely to be new primary cancers.