[Radiologic analysis of known-interval cancers after 2 years of organized mass screening for breast cancer in Ille-et-Vilaine]. / Analyse radiologique des cancers d'intervalle connus apres deux ans de campagne de dépistage de masse organisé (DMO) du cancer du sein en Ille-et-Vilaine.

The first thirty-two known interval breast cancers (appearing within the first or second year after a negative screen) occurring during a two-year breast screening round were reviewed and the radiograms analyzed. Five classes were established: true interval cancers (13/32 cases), radiologically occult cancers (2/32), cancers with no specific sign (7/32), false negative cancers (5/32) and unclassifiable cancers (5/32). In more than 50% of the cases, there was no abnormality on the initial radiographic test, although the literature reports that the rate of false-negatives in interval cancers is less than 20%. Standard classification (by at least 3 readers) is very important to provide a possible explanation of cancer development. Action should be initiated to reduce their number.