Pathologic and technical considerations in the treatment of ductal carcinoma in situ of the breast with lumpectomy and radiation therapy

Background: Lumpectomy and radiation therapy is considered a standard treat ment option for ductal carcinoma in situ (DCIS) of the breast. The incidenc e of locally recurrent carcinoma using this therapeutic approach ranges fro m 6%-19%. Multiple studies have attempted to identify factors associated wi th the development of local recurrences in these patients. Despite extensiv e reports examining this issue, no factor(s) has consistently been correlat ed with outcome. Methods: This review examines the criteria that various authors have propos ed as being associated with recurrence, including DCIS grade, size, histolo gic subtype, status of surgical margins, and technical factors to help clar ify their roles in optimizing treatment outcome. The issue of the definitio n of the type of recurrence is also addressed. Results: Though multiple studies have examined the impact of grade, histolo gic subtype, necrosis, and DCIS size on outcome, no consistent results have been observed to suggest that these factors can be routinely used to guide therapy. The adequacy of excision appears to correlate with local control but is imprecisely defined by margin status alone. Based upon recent data, it appears that atypical ductal hyperplasia and cancerization of lobules in the context of coexistent DCIS, may need to be considered as part of the D CIS lesion that should be excised. This issue may account for someof the di sparate results of different studies of DCIS. For statistical purposes, rec ent studies also suggest that only recurrences developing within or adjacen t to the bed of the initial DCIS lesion should be considered when analyzing factors associated with outcome. Recurrences developing elsewhere in the b reast may include new DCIS and invasive lesions that bear no biologic relat ionship with the initial DCIS lesion. Finally, since it is impossible to in sure that all DCIS has been removed, it may be more appropriate to consider DCIS lesions as adequately or inadequately excised instead of completely o r incompletely excised. Since DCIS is essentially a microscopic disease, pa thologists should have a primary role in helping to define the adequacy of excision. Conclusions: Additional studies with complete pathology review and longer f ollow-up are needed to reach a consensus on which prognostic factors are co nsistently associated with recurrence for patients with DCIS treated with l umpectomy and radiation therapy. At the present time, adequacy of excision appears to correlate with outcome. However, more precise and consistent met hods need to be developed to assist in the determination of adequate DCIS e xtirpation.