Ductal carcinoma in situ of the breast (DCIS) is a clinical entity which is discovered as microcalcifications on screening mammography, it rarely represents a palpable disease. Asymptomatic women with DCIS receive treatments that are similar to women with invasive breast cancer and therefore experience substantial psychological distress despite the fact that they have an excellent prognosis and normal life-expectancy. It is also true that, in spite of aggressive treatment approaches, some patients do recur.

In analogue with invasive breast cancer, DCIS is a heterogeneous disease with different prognostic profiles. The high incidence of DCIS and variations in its treatment with different outcomes led to the introduction of the Van Nuys Prognostic index (VNPI) developed in 1996 by Silverstein. This index is a simple decision-making tool to improve or at least standardise DCIS care and had been incorporated in our daily practice since 1997. Data on that experience were analysed. We tried to obtain a better understanding of the molecular behaviour of DCIS laesions and looked for predictive and prognostic markers associated with disease-free survival (DFS). The next step was the use of micro-array analysis with the Genomic Grade Index (GGI), based on four proliferation genes, and the proliferation index Ki-67. These two indices, which are considered to be predictive for the behaviour of invasive breast cancer, were incorporated into the VNPI. Furthermore, we looked if the tumour microenvironment might play a crucial role in local relapse of DCIS and risk of subsequent invasive disease. (BELG J MED ONCOL 2012;6:164–168)