Debate on neoductgenesis
Dr. Tabár proposes that some casting-type calcifications on mammography are benign, but most signify that a process called neoductgenesis is taking place, meaning the cancer is forming new ducts or duct-like structures (see Figure 3). When this occurs, the finding is usually diagnosed as DCIS at pathology, even though the process of duct formation is invasive, he said.
Michael Lagios, MD, medical director of the Breast Cancer Consultation Service in the San Francisco Bay Area, questions some of Dr. Tabár's conclusions. "There is not enough evidence to show that high-grade DCIS is invasive," he said. "Whether neoductgenesis occurs is debatable."
New ducts sometimes do grow—during puberty, for example—but they are clearly not invasive, he said. Dr. Lagios points out that for patients with extensive high-grade disease that is accurately assessed, survival rates are essentially 100%. Treatment success for these patients undermines the argument that the cancers are actually invasive rather than in situ.
Cases in which DCIS does turn fatal could represent a missed invasive cancer at the time of diagnosis, he said.
As DCIS is increasingly diagnosed, interest in breast-conserving therapy for the condition is growing, but this requires accurate assessment of margins. In a study of almost 600 women with invasive ductal carcinoma or DCIS, Dr. Tucker and his colleagues noted that large-format pathology increased the extent of DCIS detected to 16.1 mm from 6.1 mm using conventional techniques.
Using philanthropic funding, Orange Coast Memorial Medical Center in California recently adopted large-format techniques.
