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 desi gned, in which different histological characteristics of ductal carcinoma i n situ (DCIS) are reported. nuclear grade (ng), growth pattern acccording t o Andersen et nl., necrosis, size of the lesion, resection margins and foca lity. 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 f ollow-up. After a median follow-up of 63 months, 13% have developed ipsilat eral local recurrences, invasive and/or in situ. Ipsilateral local recurren ce-free survival (IL-RFS) was significantly better for patients operated wi th 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-hi gh grade) vs ng 3 thigh grade; P = 0.014), non-high-grade without comedo-ty pe 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 di ffuse) 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 s ignificant differences in IL-RFS were found in subgroups based on mode of d etection, focality or size. Ninety-four per cent of the local recurrences a fter BCT appeared at the previous operation site. Conclusions: In the BCT without RT group, combinations of either nun-high g rade and not a diffuse growth pattern or non-high grade and free margins id entified groups (constituting approximately 30% of the patients) were at lo w 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 b e questioned, and should be studied further. (C) 2000 Harcourt Publishers L td.