Diagnostic accuracy of core biopsy for ductal carcinoma in situ and its implications for surgical practice

Background: Core biopsy is considered to be a highly accurate method of gaining a preoperative histological diagnosis of breast cancer. Ductal carcinoma in situ ( DCIS) is often impalpable and is a more subtle form of breast cancer. Aim: To investigate the accuracy of core biopsy in the diagnosis of cancer in patients with DCIS. Methods: All patients who had invasive cancer (n = 959) or DCIS ( n = 92) that was confirmed by excision between 1999 and 2004 were identified. The diagnostic methods, histology of the core biopsy specimen and excision histology were reviewed in detail. Results: Core biopsy was attempted in 88% (81/92) of patients with DCIS and in 91% (874/959) of those with invasive disease. Of those patients who underwent core biopsy, a diagnosis of carcinoma on the initial core was made in 65% (53/81) of patients with DCIS compared with 92% (800/874) of patients with invasive disease (p < 0.0001). Smaller lesion size (p = 0.005) and lower grade ( p = 0.03) were associated with increased risk for a negative or non-diagnostic core in patients with DCIS. The nature of the mammographic lesion or the method of biopsy did not affect the probability of an accurate core biopsy. Patients who had a preoperative diagnosis of DCIS by core biopsy had a reoperation rate of 36% compared with 65% of those that did not have a preoperative diagnosis (p = 0.007). Conclusion: Although core biopsies are highly accurate forms of obtaining a preoperative diagnosis in patients with invasive breast cancer, this is not the case in DCIS. As the number of surgical procedures can be reduced by core biopsy, it is still of considerable value in the management of DCIS.