Predictors of invasive breast cancer in ductal carcinoma in situ initially diagnosed by core biopsy

Abstract

Background: Some patients who are initially diagnosed with ductal carcinoma in situ (DCIS) by core biopsy eventually have their disease upstaged to invasive carcinoma on final excision, thus warranting some form of axillary staging. This study aimed to identify the predictors of invasive breast cancer in DCIS diagnosed by core biopsy, which could then help clinicians decide which cases of biopsy-diagnosed DCIS should undergo concurrent sentinel lymph node biopsy during excision.

Methods: The records of 95 consecutive patients diagnosed with pure DCIS from 100 core biopsies from January 2005 to August 2007 were retrospectively reviewed. The clinical, radiological and pathological characteristics of these 100 cases were correlated with the presence of invasion or microinvasion on excision.

Results: Factors that are associated with invasive or microinvasive foci on excisional histology are: size of target lesion on radiography ≥ 20 mm [odds ratio: 6.738 (1.050-43.236), p = 0.044] and ≤ 10 cores obtained [odds ratio: 22.343 (2.351-212.385), p = 0.007].

Conclusion: Underestimation of invasive breast cancer in core biopsy-diagnosed DCIS is related to the size of the lesion on radiography, as well as the number of cores obtained during biopsy.