Outcomes and factors impacting local recurrence of ductal carcinoma in situ

We read with interest the article by Weng et al.1 It is gratifying to see further corroboration that clear margins, however defined, improve local control of ductal carcinoma in situ (DCIS) in programs employing breast-conservation therapy (BCT). However, we do not believe that the local recurrence rate of 25% for those few cases (19) with defined margins of 2 mm that met the “Lagios” criteria for breast conservation by lumpectomy alone (without irradiation) reflect what can be achieved with adequate surgery, nor would they necessarily meet the “Lagios” criteria. Margins of 2 mm for a “comedo or necrosis” subtype defined by the authors, which comprise 54.5% of the series by Weng et al.,1 are not adequate for local control in BCT with or without irradiation.2, 3 Local recurrence rates of 29% and 40%, respectively, were demonstrated for high grade DCIS with margins 1–9 mm in the Van Nuys database.4 Lagios et al.5 and Silverstein et al.2 evaluated candidacy for BCT for DCIS by use of a sequential and complete tissue processing protocol and thorough mammographic-pathologic correlation including postoperative mammographic evaluation of all patients. Their results after excision with free margins were based on this type of detailed pathologic examination performed prospectively. The authors do not explain how their resections for DCIS were examined, nor are we told whether reexcisions were performed blindly or with mammographic guidance but only that 27% of patients (23) underwent a postoperative mammogram. Lagios et al. accepted margins as narrow as 1 mm at the time, but nonetheless were able to achieve an 84% local recurrence free survival (LRFS) at 120 months of follow-up.5 Silverstein et al. were able to achieve an LRFS of 96% overall with margins of ≥ 10 mm or more.2, 3 We note that no pathologist is listed among the authors, and that no review of the actual pathology slides was performed to validate the diagnosis and margin status. Rather the diagnosis, margins, and size were determined retrospectively from the written records. We believe attempts to define the size of DCIS in particular by retrospective review of the clinical, mammographic, and pathologic reports are not reliable.6-8 Finally, we note that the authors were unable to identify an impact of pathology subtype on outcome. We suggest that had they utilized any of a number of existing classifications of DCIS that rely on nuclear grade and necrosis, rather than on an architectural-based classification determined from pathology reports retrospectively that consistently has been shown to be unable to distinguish subtypes with different outcomes, their results would have been different.2, 5, 9, 10 Michael D. Lagios M.D.*, Melvin J. Silverstein M.D. , * Breast Cancer Consultation Service,> St. Mary's Medical Center, San Francisco, California, Department of Surgery, Keck School of Medicine, Kenneth Norris Jr. Cancer Hospital, University of Southern California, Los Angeles, California