Histological type and marker expression of the primary tumour compared with its local recurrence after breast-conserving therapy for ductal carcinomain situ

We have investigated primary ductal carcinomas in situ (DCIS) of the breast and their local recurrences after breast-conserving therapy (BCT) for hist ological characteristics and marker expression. Patients who were randomize d in the EORTC trial 10853 (wide local excision versus excision plus radiot herapy) and who developed a local recurrence were identified. Histology was reviewed for 116 cases; oestrogen and progesterone receptor status, and HE R2/neu and p53 overexpression were assessed for 71 cases. Comparing the pri mary DCIS and the invasive or non-invasive recurrence, concordant histology was found in 62%, and identical marker expression in 63%. Although 11% of the recurrences developed at a distance from the primary DCIS, nearly all t hese showed the same histological and immunohistochemical profile. 5 patien ts developed well-differentiated DCIS or grade 1 invasive carcinoma after p oorly differentiated DCIS, Although these recurrences occurred in the same quadrant as the primary DCIS, they may be considered as second primary tumo urs. Only 4 patients developed poorly differentiated DCIS or grade III inva sive carcinoma after well differentiated DCIS, We conclude that in most cas es the primary DCIS and its local recurrence are related histologically or by marker expression. suggesting that local recurrence usually reflects out growth of residual DCIS; progression of well differentiated DCIS towards po orly differentiated DCIS or grade III invasive carcinoma is a non-frequent event. (C) 2001 Cancer Research Campaign.