We sought to determine factors predicting microinvasion and the prognostic role it plays in patients with ductal carcinoma in situ (DCIS).

A retrospective cohort study of 205 consecutive patients presenting to the Yale Breast Center, New Haven, CT, was performed.

Fifty-one (24.9%) patients had microinvasion on pathology. Patients with microinvasion had larger areas of DCIS and were more likely to have high-grade DCIS of the comedo and solid type associated with necrosis and microcalcifications. On multivariate analysis, none of these factors were independent predictors of microinvasion. With a median follow-up of 8.5 years, there was no difference in the recurrence rate or 5-year actuarial survival between those with microinvasion vs those with pure DCIS.

Microinvasion was associated with more extensive DCIS, higher grade, comedo or solid histology, necrosis, and microcalcifications although none of these were found to be an independent predictor of microinvasion. Furthermore, the presence of microinvasion does not seem to significantly increase the risk of recurrence or decrease survival.