Ductal Carcinoma In situ Manageable by Active Surveillance - Abstract
Background: The widespread use of mammography for breast cancer screening has increased the detection of ductal carcinoma in situ (DCIS), leading to breast cancer overdiagnosis. In this study, we investigated the clinicopathological characteristics of DCIS to determine whether it could be managed by active surveillance.
Methods: We analyzed 613 invasive ductal carcinomas (IDCs) and 220 DCIS removed by surgery in 2012. Using cancer mapping diagrams of the surgical specimens, we classified the IDC lesions into four groups according to the proportion of intraductal components: group A (?25%), group B (>25%–?50%), group C (>50%–?75%), and group D (>75%). We characterized group D and identified the DCIS cases with the same characteristics.
Results: There were 273 IDC lesions in group A (44.5%), 112 in group B (18.3%), 74 in group C (12.1%), and 154 in group D (25.1%). Compared with the other three groups, the group D included significantly more nuclear grade 1 lesions (P = 0.006), more comedo-type (P = 0.030), and more hormone receptor-negative and HER2-positive subtypes (P < 0.001). Only one DCIS lesion had all these three characteristics.
Conclusions: In this study, we assumed that IDCs with a predominant intraductal component had taken a long time to invade, and we used the proportion of intraductal components as an index of the time for invasion. Since the number of DCIS lesions exhibiting the same characteristics as the IDC lesions was too small, we could not make any conclusion on DCIS overdiagnosis.