Impact of Pathology Practice on Outcome in Published Studies of DCIS.
Recommendations for a Uniform Pathology Protocol
Michael D. Lagios;
The Breast Cancer Consultation Service
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The most significant pathologic factors for local recurrence of DCIS are nuclear grade, tumor size, and margin width. Problems in establishing these prognostic features in DCIS are that the disease is not palpable, invasion must be excluded, total extent must be calculated, all margins must be examined and margin widths must be measured. If only tissue sampling of DCIS is performed, then invasion cannot be excluded, extent cannot be calculated, and margins only will be sampled.
The definition and identification of pathologic prognostic factors is highly dependent on methodology. The USC/Van Nuys database is based on resections that are entirely and sequentially embedded with rigorous mammographic-pathologic correlation. However, the published randomized trials have not demanded such methodology, which cannot be applied retrospectively.
As a result, the randomized trials and similar studies have not found that nuclear grade, tumor size, or margins were statistically significant prognostic indicators. Therefore, the prognostic value of specific features only can be assessed within a pathologic protocol that permits complete analysis. The minimal pathologic requirement for the evaluation of DCIS is that the resection must be completely and sequentially examined microscopically.
Future DCIS intervention trials should:
- Correlate preoperative imaging, specimen radiography, and post-excision studies;
- Require complete sequential tissue processing of oriented specimens; and
- Calculate tumor size, measure margin widths, exclude microinvasive foci, and classify by grade (nuclear grade and necrosis).