Ipsilateral local recurrence in relation to therapy and morphological characteristics in patients with ductal carcinoma in situ of the breast

Method and Results: A standardized histopathological protocol has been designed, in which different histological characteristics of ductal carcinoma in situ (DCIS) are reported. nuclear grade (ng), growth pattern acccording to Andersen et nl., necrosis, size of the lesion, resection margins and focality. Using this protocol a re-evaluation of a population-based consecutive series of 306 cases of DCIS has been done as well as a thorough clinical follow-up. After a median follow-up of 63 months, 13% have developed ipsilateral local recurrences, invasive and/or in situ. Ipsilateral local recurrence-free survival (IL-RFS) was significantly better for patients operated with mastectomy (ME) or breast conserving therapy (BCT) with radiotherapy (RT) than for patients operated with BCT without RT (5-year IL-RFS 96% vs 94% vs 79%, P<0.001). In the subgroup of BCT without RT there were significant differences in IL-RFS between histopathological subgroups: ng 1 + 2 (non-high grade) vs ng 3 thigh grade; P = 0.014), non-high-grade without comedo-type necrosis vs non-high-grade with comedo-type necrosis vs high-grade (the Van Nuys classification system; P=0.025). Growth pattern (not diffuse vs diffuse) and margins (free vs involved or not evaluated) showed a tendency (P=0.07 and 0.05, respectively) to be associated to IL-RFS. In contrast, no significant differences in IL-RFS were found in subgroups based on mode of detection, focality or size. Ninety-four per cent of the local recurrences after BCT appeared at the previous operation site. Conclusions: In the BCT without RT group, combinations of either nun-high grade and not a diffuse growth pattern or non-high grade and free margins identified groups (constituting approximately 30% of the patients) were at low risk of developing ipsilateral recurrences (6-10%), compared to a 31-37% recurrence risk in the remaining groups during the observed follow-up time. The beneficial effect of post-operative RT for these low-risk groups can be questioned, and should be studied further. (C) 2000 Harcourt Publishers Ltd.