Relationship between the size and margin status of ductal carcinoma in situ of the breast and residual disease.

BACKGROUND: For women with ductal carcinoma in situ (DCIS) of the breast who have been treated with breastconserving surgery, the usefulness of size and surgical margin status (i.e., presence or absence of disease at the point of excision) as prognostic factors for predicting residual disease has not been well established. This study was conducted to determine more clearly the relationship between size and margin status of mammary DCIS to residual disease.

METHODS: The pathology records of 232 consecutive patients with mammary DCIS who had been initially treated with lumpectomy at the University Hospitals of Cleveland were retrospectively reviewed. The size of the DCIS and the surgical margins of lumpectomy were analyzed. Residual disease was defined as the persistence of DCIS in the re-excision and/or mastectomy specimens.

RESULTS: Residual disease was found in 15 of 101 patients with DCIS of less than 1.0 cm in longest dimension, in 27 of 96 patients with DCIS of 1.0-2.4 cm in size, and in 24 of 35 patients with DCIS of greater than or equal to 2.5 cm in size (P<.001). Residual disease was found in 30 of 77 patients with DCIS and positive margins, in 11 of 59 patients with DCIS and close margins (< or =1mm), and in 10 of 73 patients with DCIS and negative margins (>1 mm) (P =.001). In multivariate analysis, the occurrence of residual disease was associated with large tumor size (i.e., > or =2.5 cm) (odds ratio [OR] = 7.7; 95% confidence interval [CI] = 3.13-20.00; two-sided P = .0001) and with positive margin status (OR = 2.2; 95% CI = 1.02-4.55; two-sided P = .04).

CONCLUSIONS: The size and margin status of DCIS each were found to be independent predictors of residual disease.