Outcome of patients with ductal carcinoma in situ untreated after diagnostic biopsy

BACKGROUND: Studies of patients with ductal carcinoma in situ (DCIS) "treated" by diagnostic biopsy alone have been rare, but provide important opportunities to gain insights into the natural history of these lesions. METHODS: During a review of 1877 breast biopsy specimens in a nested case-control study of benign breast disease and breast carcinoma risk, the authors identified 13 biopsy specimens with DCIS that were originally diagnosed as benign. Because each of these women was initially given a benign diagnosis, they received no treatment beyond the diagnostic biopsy. RESULTS: When compared with women with nonproliferative lesions, the odds ratio (OR) for the development of invasive breast carcinoma among those with retrospectively identified DCIS (n = 6) was 13.5 (95% confidence interval CI, 3.7-49.7). The OR for the development of any subsequent invasive or in situ breast carcinoma event (n = 10) was 20.1 (95% CI, 6.1-66. 5). A retrospective review of these DCIS biopsy specimens revealed that the nuclear grade was low in four lesions, intermediate in six, and high in three. None showed comedo-type necrosis. Invasive carcinomas developed among women with DCIS of all nuclear grades. All 10 breast carcinoma events (100%) were in the ipsilateral breast. CONCLUSIONS: These results provided further evidence that patients with DCIS who received no treatment beyond a diagnostic biopsy were at substantially increased risk for developing ipsilateral invasive breast carcinoma, and that the increased risk in this setting was seen in DCIS of low, intermediate, and high nuclear grades.