Background: A preoperative diagnosis of ductal carcinoma in situ (DCIS) is sometimes upstaged to invasive disease postoperatively. Our objective was to clarify the predictive factors of invasive disease using preoperative imaging and to investigate the positive ratio of sentinel lymph nodes (SLN) and the incidence of invasive disease.
Methods: The subjects were 402 patients with preoperatively diagnosed ductal carcinoma without stromal invasion who underwent breast surgery with concomitant SLN surgery in January 2007 to December 2016. Of the 306 included patients, all 306 patients underwent preoperative MRI and US assessment. Outcomes were analyzed for significance using univariate and multivariate analyses.
Results: Of the 306 patients, 115 (37.6%) had invasive disease and 191 (62.4%) had DCIS only. Of the 115 patients with invasive disease, 5 (4.4%) and 4 (3.5%) had macro- and micrometastases in SLN. On the other hand, of the 191 patients with DCIS, only 1 (0.5%) had a micrometastasis. Predictors of invasive disease in the univariate analysis included having a palpable mass, were varied by biopsy method, having a US hypoechoic mass, MRI enhancement, or MRI large enhanced lesion; the size of the mass enhancement ≥ 1.1 cm or a spread of non-mass enhancement ≥ 3.1 cm (P = 0.003). Predictors of invasive disease in the multivariate analysis included US hypoechoic mass and MRI large enhanced lesion.
Conclusion: We need to perform SLN biopsy for preoperatively diagnosed DCIS when patients have predictors of invasive disease, but SLN biopsy will no longer be essential for patients when they have no predictors of invasive disease.
Keywords: DCIS; MRI; Predictive factors; SLN biopsy; US.