Histopathologic and Cytochemical Characteristics of Interval Breast Carcinomas from the Stockholm Mammography Screening Project

Combined morphological and cytochemical malignancy grading in addition to tumor stage was applied to assess the malignant potential of so-called interval carcinomas from the Stockholm randomized mammography screening study. Only interval carcinomas surfacing within two years from screening were included. Fifty-four percent of the tumors were in stage I and 46% of the carcinomas eligible for DNA analysis were diploid, i.e. low-malignant. An overrepresentation of prognostically unfavorable tumor characteristics was found only within the subgroup 'true' and 'early' interval cancer.