THE PATHOLOGICAL AND BIOLOGICAL NATURE OF SCREEN-DETECTED BREAST CARCINOMAS - A MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY

Traditional and immunohistochemical markers of prognosis were examined in 455 mammary carcinomas derived from breast cancer screening and co mpared with those of 277 carcinomas presenting symptomatically over th e same period. Tumours detected by population screening under the U.K. National Health Service Programme do not differ from those detected b y other screening projects, but compared with symptomatic cancers, scr een-detected cancers are more likely to be in situ and if invasive, to be smaller, of lower grade, and to have invaded vessels, perineural s paces, and lymph nodes less frequently. Tubular and cribriform types a re more often represented in screened patients. Immunohistochemical ma rkers which have been proposed as being related to likely tumour behav iour (epidermal growth factor receptor, c-erbB-2 protein, oestrogen an d progesterone receptors, cathepsin D, p53, and retinoblastoma protein ) do not distinguish screen-detected from 'clinical' cancers. It is co ncluded that cancers diagnosed at screening do not differ biologically from those presenting clinically, but are the same lesions detected a t an earlier stage of their natural history. (C) 1997 by John Wiley & Sons, Ltd.