Risk factors for invasive breast cancer when core needle biopsy shows ductal carcinoma in situ.

HYPOTHESIS A core needle biopsy (CNB) diagnosis of ductal carcinoma in situ (DCIS) may be associated with a final diagnosis of invasive cancer. Preoperative radiologic, clinical, and pathological features may identify patients at high risk of diagnostic upstaging, who may be appropriate candidates for sentinel node biopsy at initial surgery. DESIGN Review of prospectively collected database. SETTING Tertiary teaching referral hospital and a population-based breast screening center. PATIENTS Consecutive patients from January 1, 1994, to December 31, 2006, whose CNB findings showed DCIS or DCIS with microinvasion. MAIN OUTCOME MEASURES Upstaging to invasive cancer. RESULTS Eleven of 15 cases of DCIS with microinvasion (73.3%) and 65 of 375 cases of DCIS (17.3%) were upstaged to invasive cancer. Ten of 21 palpable lesions (47.6%) were found to have microinvasion. For impalpable DCIS, multivariate analysis showed that noncalcific mammographic features (mass, architectural distortion, or nonspecific density) (odds ratio [95% confidence interval], 2.00 [1.02-3.94]), mammographic size of 20 mm or greater (2.80 [1.46-5.38]), and prolonged screening interval of 3 years or longer (4.41 [1.60-12.13]) were associated with upstaging. The DCIS grade on CNB was significant on univariate analysis (P = .04). The rate of upstaging increased with the number of significant factors present in a patient: 8.3% in patients with no risk factors, 20.8% in those with 1 risk factor, 39.6% in those with 2 risk factors, and 57.1% in those with 3 risk factors. CONCLUSIONS The risk of upstaging can be estimated by using preoperative features in patients with DCIS on CNB. We propose a management algorithm that includes sentinel node biopsy for patients with DCIS who have microinvasion on CNB, palpable DCIS, 2 or more predictive factors, and planned total mastectomy.